https://go.usa.gov/xEuRU

Nat’l Highway Traffic Safety Admin., DOT § 571.116

(d) Note the vehicle position.

(e) Release the parking brake. Re-lease the service brakes.

(f) Remove the key.

(g) Verify that the gear selection control or transmission is locked in ‘‘park.’’

(h) Verify that the vehicle, at rest, has moved no more than 150 mm from the position noted prior to release of the brakes.

S6.2.3

(a) Drive the vehicle forward down a

10 percent grade and stop it with the service brakes.

(b) Apply the parking brake (if present).

(c) Move the gear selection control to ‘‘park.’’

(d) Note the vehicle position.

(e) Release the parking brake. Re-lease the service brakes.

(f) Remove the key.

(g) Verify that the gear selection control or transmission is locked in ‘‘park.’’

(h) Verify that the vehicle, at rest, has moved no more than 150 mm from the position noted prior to release of the brakes.

[71 FR 17755, Apr. 7, 2006, as amended at 75 FR 15624, Mar. 30, 2010]

§ 571.115 [Reserved]

§ 571.116 Standard No. 116; Motor ve-hicle brake fluids.

S1. Scope. This standard specifies re-quirements for fluids for use in hydrau-lic brake systems of motor vehicles, containers for these fluids, and labeling of the containers.

S2. Purpose. The purpose of this standard is to reduce failures in the hy-draulic braking systems of motor vehi-cles which may occur because of the manufacture or use of improper or con-taminated fluid.

S3. Application. This standard applies to all fluid for use in hydraulic brake systems of motor vehicles. In addition, S5.3 applies to passenger cars, multi-purpose passenger vehicles, trucks, buses, trailers, and motorcycles.

S4. Definitions.

Blister means a cavity or sac on the surface of a brake cup.

Brake fluid means a liquid designed for use in a motor vehicle hydraulic brake system in which it will contact elastomeric components made of sty-rene and butadiene rubber (SBR), ethylene and propylene rubber (EPR), polychloroprene (CR) brake hose inner tube stock or natural rubber (NR).

Chipping means a condition in which small pieces are missing from the outer surface of a brake cup.

Duplicate samples means two samples of brake fluid taken from a single packaged lot and tested simulta-neously.

Hydraulic system mineral oil means a mineral-oil-based fluid designed for use in motor vehicle hydraulic brake sys-tems in which the fluid is not in con-tact with components made of SBR, EPR or NR.

Packager means any person who fills containers with brake fluid that are subsequently distributed for retail sale.

Packaged lot is that quantity of brake fluid shipped by the manufacturer to the packager in a single container, or that quantity of brake fluid manufac-tured by a single plant run of 24 hours or less, through the same processing equipment and with no change in in-gredients.

Scuffing means a visible erosion of a portion of the outer surface of a brake cup.

A silicone base brake fluid (SBBF) is a brake fluid which consists of not less than 70 percent by weight of a diorgano polysiloxane.

Sloughing means degradation of a brake cup as evidenced by the presence of carbon black loosely held on the brake cup surface, such that a visible black streak is produced when the cup, with a 500 ±10 gram deadweight on it, is drawn base down over a sheet of white bond paper placed on a firm flat sur-face.

Stickiness means a condition on the surface of a brake cup such that fibers will be pulled from a wad of U.S.P. ab-sorbent cotton when it is drawn across the surface.

S5. Requirements. This section speci-fies performance requirements for DOT 3, DOT 4 and DOT 5 brake fluids; re-quirements for brake fluid certifi-cation; and requirements for container sealing, labeling and color coding for brake fluids and hydraulic system min-eral oils. Where a range of tolerances is

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00547 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31kp ay ne o n V

M O

F R

W

IN

w ith

JO

B

49 CFR Ch. V (10–1–18 Edition) § 571.116 specified, the brake fluid shall meet the requirements at all points within the range.

S5.1 Brake fluid. When tested in ac-cordance with S6, brake fluids shall meet the following requirements:

S5.1.1 Equilibrium reflux boiling point (ERBP). When brake fluid is tested ac-cording to S6.1, the ERBP shall not be less than the following value for the grade indicated:

(a) DOT 3: 205 °C. (401 °F.).

(b) DOT 4: 230 °C. (446 °F.).

(c) DOT 5: 260 °C. (500 °F.).

S5.1.2 Wet ERBP. When brake fluid is tested according to S6.2, the wet ERBP shall not be less than the fol-lowing value for the grade indicated:

(a) DOT 3: 140 °C. (284 °F.).

(b) DOT 4: 155 °C. (311 °F.).

(c) DOT 5: 1 180 °C. (356 °F.).

S5.1.3. Kinematic viscosities. When brake fluid is tested according to S6.3, the kinematic viscosities in square millimeters per second at stated tem-peratures shall be neither less than 1.5 mm2/s at 100 °C. (212 °F.) nor more than the following maximum value for the grade indicated:

(a) DOT 3: 1,500 mm2/s at minus 40 °C.

(minus 40 °F.).

(b) DOT 4: 1,800 mm2/s at minus 40 °C.

(minus 40 °F.).

(c) DOT 5: 900 mm2/s at minus 40 °C.

(minus 40 °F.).

S5.1.4 pH value. When brake fluid, except DOT 5 SBBF, is tested according to S6.4, the pH value shall not be less than 7.0 nor more than 11.5.

S5.1.5 Brake fluid stability.

S5.1.5.1 High-temperature stability.

When brake fluid is tested according to S6.5.3 the ERBP shall not change by more than 3 °C. (5.4 °F.) plus 0.05° for each degree that the ERBP of the fluid exceeds 225 °C. (437 °F.).

S5.1.5.2 Chemical stability. When brake fluid, except DOT 5 SBBF, is tested according to S6.5.4, the change in temperature of the refluxing fluid mixture shall not exceed 3.0 °C (5.4 °F.)

plus 0.05° for each degree that the ERBP of the fluid exceeds 225 °C (437 °F.).

S5.1.6 Corrosion. When brake fluid is tested according to S6.6—

(a) The metal test strips shall not show weight changes exceeding the limits stated in Table I.

TABLE I

Test strip material

Maximum permissible weight change, mg./sq.

cm. of sur-face

Steel, tinned iron, cast iron ................................. 0.2 Aluminum Brass, copper

(b) Excluding the area of contact (13 ±1 mm. (1⁄2 ±1⁄32 inch) measured from the bolt hole end of the test strip), the metal test strips shall not show pitting or etching to an extent discernible without magnification;

(c) The water-wet brake fluid at the end of the test shall show no jelling at 23 ±5 °C (73.4 ±9 °F.);

(d) No crystalline deposit shall form and adhere to either the glass jar walls or the surface of the metal strips;

(e) At the end of the test, sedimenta-tion of the water-wet brake fluid shall not exceed 0.10 percent by volume;

(f) The pH value of water-wet brake fluid, except DOT 5 SBBF, at the end of the test shall not be less than 7.0 nor more than 11.5;

(g) The cups at the end of the test shall show no disintegration, as evi-denced by blisters or sloughing;

(h) The hardness of the cup shall not decrease by more than 15 International Rubber Hardness Degrees (IRHD); and

(i) The base diameter of the cups shall not increase by more than 1.4

mm. (0.055 inch).

S5.1.7 Fluidity and appearance at low temperature. When brake fluid is tested according to S6.7, at the storage tem-perature and for the storage times given in Table II—

(a) The fluid shall show no sludging, sedimentation, crystallization, or stratification;

(b) Upon inversion of the sample bot-tle, the time required for the air bubble to travel to the top of the fluid shall not exceed the bubble flow times shown in Table II; and

(c) On warming to room temperature, the fluid shall resume the appearance and fluidity that it had before chilling.

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00548 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31kp ay ne o n V

M O

F R

W

IN

w ith

TABLE II—FLUIDITY AND APPEARANCE AT LOW

TEMPERATURES

Storage temperature Storage time (hours)

Maximum bubble flow time (seconds)

Minus 40 ±2 °C. (minus 40 ±3.6 °F.) ............................................. 144 ±4.0 10

Minus 50 ±2 °C. (minus 58 ±3.6 °F.) ............................................. 6 ±0.2 35

S5.1.8 [Reserved] S5.1.9 Water tolerance. (a) At low tem-perature. When brake fluid is tested ac-cording to S6.9.3(a)—

(1) The fluid shall show no sludging, sedimentation, crystallization, or stratification;

(2) Upon inversion of the centrifuge tube, the air bubble shall travel to the top of the fluid in not more than 10 sec-onds;

(3) If cloudiness has developed, the wet fluid shall regain its original clar-ity and fluidity when warmed to room temperature; and

(b) At 60 °C. (140 °F.). When brake fluid is tested according to S6.9.3(b)—

(1) The fluid shall show no stratifica-tion; and

(2) Sedimentation shall not exceed

0.15 percent by volume after centrifuging.

S5.1.10 Compatibility.

(a) At low temperature. When brake fluid is tested according to S6.10.3(a), the test specimen shall show no sludging, sedimentation, or crystalliza-tion. In addition, fluids, except DOT 5 SBBF, shall show no stratification.

(b) At 60 °C. (140 °F.). When brake fluid is tested according to S6.10.3(b)—

(1) Sedimentation shall not exceed

0.05 percent by volume after centrifuging; and

(2) Fluids, except DOT 5 SBBF, shall show no stratification.

S5.1.11 Resistance to oxidation. When brake fluid is tested according to S6.11—

(a) The metal test strips outside the areas in contact with the tinfoil shall not show pitting or etching to an ex-tent discernible without magnification;

(b) No more than a trace of gum shall be deposited on the test strips outside the areas in contact with the tinfoil;

(c) The aluminum strips shall not change in weight by more than 0.05 mg./sq. cm.; and

(d) The cast iron strips shall not change in weight by more than 0.3 mg./

sq. cm.

S5.1.12 Effects on cups. When brake cups are subjected to brake fluid in ac-cordance with S6.12—

(a) The increase in the diameter of the base of the cups shall be not less than 0.15 mm. (0.006 inch) or more than

1.40 mm. (0.055 inch);

(b) The decrease in hardness of the cups shall be not more than 10 IRHD at 70 °C. (158 °F.) or more than 15 IRHD at 120 °C. (248 °F.), and there shall be no increase in hardness of the cups; and

(c) The cups shall show no disintegra-tion as evidenced by stickiness, blis-ters, or sloughing.

S5.1.13 Stroking properties. When brake fluid is tested according to S6.13—

(a) Metal parts of the test system shall show no pitting or etching to an extent discernible without magnifica-tion;

(b) The change in diameter of any cylinder or piston shall not exceed 0.13

mm. (0.005 inch);

(c) The average decrease in hardness of seven of the eight cups tested (six wheel cylinder and one master cylinder primary) shall not exceed 15 IRHD. Not more than one of the seven cups shall have a decrease in hardness greater than 17 IRHD;

(d) None of the eight cups shall be in an unsatisfactory operating condition as evidenced by stickiness, scuffing, blisters, cracking, chipping, or other change in shape from its original ap-pearance;

(e) None of the eight cups shall show an increase in base diameter greater than 0.90 mm (0.035 inch);

(f) The average lip diameter set of the eight cups shall not be greater than 65 percent.

(g) During any period of 24,000 strokes, the volume loss of fluid shall not exceed 36 milliliters;

(h) The cylinder pistons shall not freeze or function improperly through-out the test;

(i) The total loss of fluid during the 100 strokes at the end of the test shall not exceed 36 milliliters;

(j) The fluid at the end of the test shall show no formation of gels;

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00549 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31kp ay ne o n V

M O

F R

W

IN

w ith

(k) At the end of the test the amount of sediment shall not exceed 1.5 percent by volume; and

(l) Brake cylinders shall be free of de-posits that are abrasive or that cannot be removed when rubbed moderately with a nonabrasive cloth wetted with ethanol.

S5.1.14 Fluid color. Brake fluid and hydraulic system mineral oil shall be of the color indicated:

DOT 3, DOT 4, and DOT 5.1 non-SBBF—color-less to amber.

DOT 5 SBBF—purple.

Hydraulic system mineral oil—green.

S5.2 Packaging and labeling require-ments for motor vehicle brake fluids.

S5.2.1 Container sealing. Each brake fluid or hydraulic system mineral oil container with a capacity of 177 mL or more shall be provided with a reseal-able closure that has an inner seal im-pervious to the packaged brake fluid.

The container closure shall include a tamper-proof feature that will either be destroyed or substantially altered when the container closure is initially opened.

S5.2.2 Certification, marking, and la-beling.

S5.2.2.1 Each manufacturer of a DOT grade brake fluid shall furnish to each packager, distributor, or dealer to whom he delivers brake fluid, the fol-lowing information:

(a) A serial number identifying the production lot and the date of manu-facture of the brake fluid.

(b) The grade (DOT 3, DOT 4, DOT 5) of the brake fluid. If DOT 5 grade brake fluid , it shall be further distinguished as ‘‘DOT 5 SILICONE BASE’’ or ‘‘DOT

5.1 NON-SILICONE BASE.’’

(c) The minimum wet boiling point in Fahrenheit of the brake fluid.

(d) Certification that the brake fluid conforms to § 571.116.

S5.2.2.2 Each packager of brake fluid shall furnish the information specified in paragraphs (a) through (g) of this S5.2.2.2 by clearly marking it on each brake fluid container or on a label (la-bels) permanently affixed to the con-tainer, in any location except a remov-able part such as a lid. After being sub-jected to the operations and conditions specified in S6.14, the information re-quired by this section shall be legible to an observer having corrected visual acuity of 20/40 (Snellen ratio) at a dis-tance of 305 mm, and any label affixed to the container in compliance with this section shall not be removable without its being destroyed or defaced.

(a) Certification that the brake fluid conforms to § 571.116.

(b) The name of the packager of the brake fluid, which may be in code form.

(c) The name and complete mailing address of the distributor.

(d) A serial number identifying the packaged lot and date of packaging.

(e) Designation of the contents as

‘‘DOT—MOTOR VEHICLE BRAKE

FLUID’’ (Fill in DOT 3, DOT 4, DOT 5 SILICONE BASE, or DOT 5.1 NON-SIL- ICONE BASE as applicable).

(f) The minimum wet boiling point in Fahrenheit of the DOT brake fluid in the container.

(g) The following safety warnings in capital and lower case letters as indi-cated:

(1) FOLLOW VEHICLE MANUFAC-

TURER’S RECOMMENDATIONS

WHEN ADDING BRAKE FLUID.

(2) KEEP BRAKE FLUID CLEAN

AND DRY. Contamination with dirt, water, petroleum products or other ma-terials may result in brake failure or costly repairs.

(3) STORE BRAKE FLUID ONLY IN

ITS ORIGINAL CONTAINER. KEEP

CONTAINER CLEAN AND TIGHTLY

CLOSED TO PREVENT ABSORPTION

OF MOISTURE.

(4) CAUTION: DO NOT REFILL CON-

TAINER, AND DO NOT USE FOR

OTHER LIQUIDS. (Not required for containers with a capacity in excess of 19 L.)

S5.2.2.3 Each packager of hydraulic system mineral oil shall furnish the in-formation specified in paragraphs (a) through (e) of this S5.2.2.3 by clearly marking it on each brake fluid con-tainer or on a label (labels) perma-nently affixed to the container, in any location except a removable part such as a lid. After being subjected to the operations and conditions specified in S6.14, the information required by this section shall be legible to an observer having corrected visual acuity of 20/40 (Snellen ratio) at a distance of 305 mm and any label affixed to the container in compliance with this section shall

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00550 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31kp ay ne o n V

M O

F R

W

IN

w ith not be removable without its being de-stroyed or defaced.

(a) The name of the packager of the hydraulic system mineral oil, which may be in code form.

(b) The name and complete mailing address of the distributor.

(c) A serial number identifying the packaged lot and date of packaging.

(d) Designation of the contents as

‘‘HYDRAULIC SYSTEM MINERAL

OIL’’ in capital letters at least 3 mm high.

(e) The following safety warnings in capital and lower case letters as indi-cated:

(1) FOLLOW VEHICLE MANUFAC-

TURER’S RECOMMENDATIONS

WHEN ADDING HYDRAULIC SYSTEM

MINERAL OIL.

(2) Hydraulic System Mineral Oil is NOT COMPATIBLE with the rubber components of brake systems designed for use with DOT brake fluids.

(3) KEEP HYDRAULIC SYSTEM

MINERAL OIL CLEAN. Contamination with dust or other materials may re-sult in brake failure or costly repair.

(4) CAUTION: STORE HYDRAULIC

SYSTEM MINERAL OIL ONLY IN ITS

ORIGINAL CONTAINER. KEEP CON-

TAINER CLEAN AND TIGHTLY

CLOSED. DO NOT REFILL CON-

TAINER OR USE OTHER LIQUIDS.

(The last sentence is not required for containers with a capacity in excess of 19 L.)

S5.2.2.4 If a container for brake fluid or hydraulic system mineral oil is not normally visible but designed to be protected by an outer container or car-ton during use, the outer container or carton rather than the inner container shall meet the labeling requirements of S5.2.2.2 or S5.2.2.3, as appropriate.

S5.3 Motor vehicle requirement. Each passenger car, multipurpose passenger vehicle, truck, bus, trailer, and motor-cycle that has a hydraulic brake sys-tem shall be equipped with fluid that has been manufactured and packaged in conformity with the requirements of this standard.

S6. Test procedures.

S6.1 Equilibrium reflux boiling point.

Determine the ERBP of a brake fluid by running duplicate samples accord-ing to the following procedure and averaging the results.

S6.1.1 Summary of procedure. Sixty milliliters (ml.) of brake fluid are boiled under specified equilibrium con-ditions (reflux) at atmospheric pressure in a 100-ml. flask. The average tem-perature of the boiling fluid at the end of the reflux period, corrected for vari-ations in barometric pressure if nec-essary, is the ERBP.

S6.1.2 Apparatus. (See Figure 1) The test apparatus shall consist of—

(a) Flask. (See Figure 2) A 100-ml.

round-bottom, short-neck heat-resist-ant glass flask having a neck with a 19⁄38 standard taper, female ground-glass joint and a side-entering tube, with an outside diameter of 10 millime-ters (mm.), which centers the ther-mometer bulb in the flask 6.5 mm. from the bottom;

(b) Condenser. A water-cooled, reflux, glass-tube type, condenser having a jacket 200 mm. in length, the bottom end of which has a 19⁄38 standard-taper, drip-tip, male ground-glass joint;

(c) Boiling stones. Three clean, unused silicon carbide grains (approximately 2

mm. (0.08 inch) in diameter, grit No. 8);

(d) Thermometer. Standardized cali-brated partial immersion (76 mm.), solid stem, thermometers conforming to the requirements for an ASTM 2C or 2F, and an ASTM 3C or 3F thermom-eter; and

(e) Heat source. Variable autotransformer-controlled heating mantle designed to fit the flask, or an electric heater with rheostat heat con-trol.

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00551 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31kp ay ne o n V

M O

F R

W

IN

w ith

FIG. 1—BOILING POINT TEST APPARATUS

FIG. 2—DETAIL OF 100 ML SHORT-NECK FLASK

S6.1.3 Preparation of apparatus. (a)

Thoroughly clean and dry all glass-ware.

(b) Insert thermometer through the side tube until the tip of the bulb is 6.5

mm. (1⁄4 inch) from the bottom center of the flask. Seal with a short piece of natural rubber, EPDM, SBR, or butyl tubing.

(c) Place 60 ±1 ml. of brake fluid and the silicon carbide grains into the flask.

(d) Attach the flask to the condenser.

When using a heating mantle, place the mantle under the flask and support it with a ring-clamp and laboratory-type stand, holding the entire assembly in place by a clamp. When using a rheo-stat-controlled heater, center a stand-ard porcelain or hard asbestos refrac-tory, having a diameter opening 32 to 38 mm., over the heating element and mount the flask so that direct heat is applied only through the opening in the refractory. Place the assembly in an area free from drafts or other types of sudden temperature changes. Con-nect the cooling water inlet and outlet tubes to the condenser. Turn on the cooling water. The water supply tem-perature shall not exceed 28 °C. (82.4 °F.) and the temperature rise through the condenser shall not exceed 2 °C. (3.6 °F.).

S6.1.4 Procedure. Apply heat to the flask so that within 10 ±2 minutes the fluid is refluxing in excess of 1 drop per second. The reflux rate shall not exceed 5 drops per second at any time. Imme-diately adjust the heating rate to ob-tain an equilibrium reflux rate of 1 to 2 drops per second over the next 5 ±2 minutes. Maintain this rate for an ad-ditional 2 minutes, taking four tem-perature readings at 30–second inter-vals. Record the average of these as the observed ERBP. If no reflux is evident when the fluid temperature reaches 260 °C (500 °F), discontinue heating and re-port ERBP as in excess of 260 °C (500 °F).

S6.1.5 Calculation. (a) Thermometer inaccuracy. Correct the observed ERBP by applying any correction factor ob-tained in standardizing the thermom-eter.

(b) Variation from standard barometric pressure. Apply the factor shown in Table III to calculate the barometric pressure correction to the ERBP.

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00552 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31 E C

A

U

.0

E C

A

U

.0 kp ay ne o n V

M O

F R

W

IN

w ith

TABLE III—CORRECTION FOR BAROMETRIC

PRESSURE

Observed ERBP corrected for thermometer inaccuracy

Correction per 1 mm difference in pressure a

°C. (°F.)

100 °C. (212 °F.) to 190 °C. (374 °F.) ............................................. 0.039 (0.07)

Over 190 °C. (374 °F.) .................. 0.04 (0.08) a To be added in case barometric pressure is below 760 mm.; to be subtracted in case barometric pressure is above 670 mm.

(c) If the two corrected observed ERBP’s agree within 2 °C. (4 °C. for brake fluids having an ERBP over 230 °C./446 °F.) average the duplicate runs as the ERBP; otherwise, repeat the en-tire test, averaging the four corrected observed values to determine the origi-nal ERBP.

S6.2 Wet ERBP. Determine the wet ERBP of a brake fluid by running du-plicate samples according to the fol-lowing procedure.

S6.2.1. Summary of procedure. A 350

ml. sample of the brake fluid is hu-midified under controlled conditions;

350 ml. of SAE triethylene glycol monomethyl ether, brake fluid grade, referee material (TEGME) as described in appendix E of SAE Standard J1703 NOV83 (incorporated by reference, see § 571.5), is used to establish the end point for humidification. After humidi-fication, the water content and ERBP of the brake fluid are determined.

S6.2.2 Apparatus for humidification.

(See Figure 3).

Test apparatus shall consist of—

(a) Glass jars. Four SAE RM–49 corro-sion test jars or equivalent screwtop, straight-sided, round glass jars each having a capacity of about 475 ml. and approximate inner dimensions of 100

mm. in height by 75 mm. in diameter, with matching lids having new, clean inserts providing water-vapor-proof seals;

(b) Desiccator and cover. Two bowl-form glass desiccators, 250-mm. inside diameter, having matching tubulated covers fitted with No. 8 rubber stop-pers; and

(c) Desiccator plate. Two 230-mm. di-ameter, perforated porcelain desiccator plates, without feet, glazed on one side.

S6.2.3 Reagents and materials. (a) Dis-tilled water, see S7.1.

(b) SAE TEGME referee material (see appendix E of SAE Standard J1703 NOV83 (incorporated by reference, see § 571.5)).

S6.2.4 Preparation of apparatus. Lu-bricate the ground-glass joint of the desiccator. Pour 450 ±10 ml. of distilled water into each desiccator and insert perforated porcelain desiccator plates.

Place the desiccators in an oven with temperature controlled at 50 ±1 °C. (122 ±1.8 °F.) throughout the humidification procedure.

S6.2.5 Procedure. Pour 350 ±5 ml. of brake fluid into an open corrosion test jar. Prepare in the same manner a du-plicate test fluid sample and two dupli-cate specimens of the SAE TEGME ref-eree material (350 ±5 ml. of TEGME in each jar). The water content of the SAE TEGME fluid is adjusted to 0.50 ±0.05 percent by weight at the start of the test in accordance with S7.2. Place one sample each of the test brake fluid and the prepared TEGME sample into the same desiccator. Repeat for the second sample of test brake fluid and TEGME in a second desiccator. Place the desiccators in the 50 °C. (122 °F.)

controlled oven and replace desiccator covers. At intervals, during oven hu-midification, remove the rubber stop-pers in the tops of desiccators. Using a long needled hypodermic syringe, take a sample of not more than 2 ml. from each TEGME sample and determine its water content. Remove no more than 10 ml. of fluid from each SAE TEGME sample during the humidification pro-cedure. When the water content of the SAE fluid reaches 3.70 ±0.05 percent by weight (average of the duplicates). re-move the two test fluid specimens from their desiccators and promptly cap each jar tightly. Allow the sealed jars to cool for 60 to 90 minutes at 23° ±5 °C.

(73.4° ±9 °F.). Measure the water con-tents of the test fluid specimens in ac-cordance with S7.2 and determine their ERBP’s in accordance with S6.1. If the two ERBPs agree within 4 °C. (8 °F.), average them to determine the wet ERBP; otherwise repeat and average the four individual ERBPs as the wet ERBP of the brake fluid.

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00553 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31kp ay ne o n V

M O

F R

W

IN

w ith

S6.3 Kinematic viscosities. Determine the kinematic viscosity of a brake fluid in mm2/s by the following proce-dure. Run duplicate samples at each of the specified temperatures, making two timed runs on each sample.

S6.3.1 Summary of the procedure. The time is measured for a fixed volume of the brake fluid to flow through a cali-brated glass capillary viscometer under an accurately reproducible head and at a closely controlled temperature. The kinematic viscosity is then calculated from the measured flow time and the calibration constant of the viscometer.

S6.3.2 Apparatus.

(a) Viscometers. Calibrated glass cap-illary-type viscometers, ASTM D2515– 66 (incorporated by reference, see § 571.5), measuring viscosity within the precision limits of S6.4.7. Use Cannon- Fenske Routine or other modified Ostwald viscometers at ambient tem-peratures and above.

(b) Viscometer holders and frames.

Mount a viscometer in the constant-temperature bath so that the mounting tube is held within 1° of the vertical.

(c) Viscometer bath. A transparent liq-uid bath of sufficient depth such that at no time during the measurement will any portion of the sample in the

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00554 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31 E C

A

U

.0

/G

P H kp ay ne o n V

M O

F R

W

IN

w ith viscometer be less than 2 cm. below the surface or less than 2 cm. above the bottom. The bath shall be cylindrical in shape, with turbulent agitation suf-ficient to meet the temperature con-trol requirements. For measurements within 15° to 100 °C. (60° to 212 °F.) the temperature of the bath medium shall not vary by more than 0.01 °C. (0.02 °F.)

over the length of the viscometers, or between the positions of the viscometers, or at the locations of the thermometers. Outside this range, the variation shall not exceed 0.03 °C. (0.05 °F.).

(d) Thermometers. Liquid-in-Glass Kinematic Viscosity Test Thermom-eters, covering the range of test tem-peratures indicated in Table IV and conforming to ASTM E1–68 (incor-porated by reference, see § 571.5), and in the IP requirements for IP Standard Thermometers. Use two standardized thermometers in the bath.

TABLE IV—KINEMATIC VISCOSITY THERMOMETERS

Temperature range For tests at Subdivisions Thermometer number

°C. °F. °C. °F. °C. °F. ASTM IP

Minus 55.3 to minus 52.5 .. Minus 67.5 to minus 62.5 Minus 55 .. Minus 67 .. 0.05 0.1 74 F 69 F. or C.

Minus 41.4 to minus 38.6 .. Minus 42.5 to minus 37.5 Minus 40 .. Minus 40 .. 0.05 0.1 73 F 68 F. or C.

98.6 to 101.4 ..................... 207.5 to 212.5 ................... 100 ........... 212 ........... 0.05 0.1 30 F 32 F. or C.

(e) Timing device. Stop watch or other timing device graduated in divisions representing not more than 0.2 second, with an accuracy of at least ±0.05 per-cent when tested over intervals of 15 minutes. Electrical timing devices may be used when the current frequency is controlled to an accuracy of 0.01 per-cent or better.

S6.3.3 Standardization.

(a) Viscometers. Use viscometers cali-brated in accordance with appendix 1 of ASTM D445–65 (incorporated by ref-erence, see § 571.5). The calibration con-stant, C, is dependent upon the gravita-tional acceleration at the place of cali-bration. This must, therefore, be sup-plied by the standardization laboratory together with the instrument constant.

Where the acceleration of gravity, g, in the two locations differs by more than

0.1 percent, correct the calibration con-stant as follows:

C2 = (g2/g1) × C1 where the subscripts 1 and 2 indicate respectively the standardization lab-oratory and the testing laboratory.

(b) Thermometers. Check liquid-in-glass thermometers to the nearest 0.01 °C. (0.02 °F.) by direct comparison with a standardized thermometer. Kine-matic Viscosity Test Thermometers shall be standardized at ‘‘total immer-sion.’’ The ice point of standardized thermometers shall be determined be-fore use and the official corrections shall be adjusted to conform to the changes in ice points. (See ASTM E77– 66 (incorporated by reference, see § 571.5)).

(c) Timers. Time signals are broadcast by the National Bureau of Standards, Station WWV, Washington, DC at 2.5, 5, 10, 15, 20, 25, 30, and 35 Mc/sec (MHz).

Time signals are also broadcast by Sta-tion CHU from Ottawa, Canada, at 3.330, 7.335, and 14.670 Mc/sec, and Sta-tion MSF at Rugby, United Kingdom, at 2.5, 5, and 10 Mc/sec.

S6.3.4 Procedure. (a) Set and main-tain the bath at the appropriate test temperature (see S5.1.3) within the lim-its specified in S6.3.2(c). Apply the nec-essary corrections, if any, to all ther-mometer readings.

(b) Select a clean, dry, calibrated vis-cometer giving a flow time not less than its specified minimum, or 200 sec-onds, whichever is the greater.

(c) Charge the viscometer in the manner used when the instrument was calibrated. Do not filter or dry the brake fluid, but protect it from con-tamination by dirt and moisture dur-ing filling and measurements.

(1) Charge the suspended level viscometers by tilting about 30° from the vertical and pouring sufficient brake fluid through the fill tube into the lower reservoir so that when the viscometer is returned to vertical posi-tion the meniscus is between the fill marks. For measurements below 0 °C.

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00555 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31kp ay ne o n V

M O

F R

W

IN

w ith

(32 °F.), before placing the filled vis-cometer into the constant temperature bath, draw the sample into the working capillary and timing bulb and insert small rubber stoppers to suspend the fluid in this position, to prevent accu-mulation of water condensate on the walls of the critical portions of the vis-cometer. Alternatively, fit loosely packed drying tubes into the open ends of the viscometer to prevent water con-densation, but do not restrict the flow of the sample under test by the pres-sures created in the instrument.

(2) If a Cannon-Fenske Routine vis-cometer is used, charge by inverting and immersing the smaller arm into the brake fluid and applying vacuum to the larger arm. Fill the tube to the upper timing mark, and return the vis-cometer to an upright position.

(d) Mount the viscometer in the bath in a true vertical position (see S6.3.2(b)).

(e) The viscometer shall remain in the bath until it reaches the test tem-perature.

(f) At temperatures below 0 °C. (32 °F.) conduct an untimed preliminary run by allowing the brake fluid to drain through the capillary into the lower reservoir after the test tempera-ture has been established.

(g) Adjust the head level of the brake fluid to a position in the capillary arm about 5 mm. above the first timing mark.

(h) With brake fluid flowing freely measure to within 0.2 second the time required for the meniscus to pass from the first timing mark to the second. If this flow time is less than the min-imum specified for the viscometer, or 200 seconds, whichever is greater, re-peat using a viscometer with a cap-illary of smaller diameter.

(i) Repeat S6.3.4 (g) and (h). If the two timed runs do not agree within 0.2 percent, reject and repeat using a fresh sample of brake fluid.

S6.3.5 Cleaning the viscometers. (a) Periodically clean the instrument with chromic acid to remove organic depos-its. Rinse thoroughly with distilled water and acetone, and dry with clean dry air.

(b) Between successive samples rinse the viscometer with ethanol (isopropanol when testing DOT 5 fluids) followed by an acetone or ether rinse.

Pass a slow stream of filtered dry air through the viscometer until the last trace of solvent is removed.

S6.3.6 Calculation. (a) The following viscometers have a fixed volume charged at ambient temperature, and as a consequence C varies with test temperature: Cannon-Fenske Routine, Pinkevitch, Cannon-Manning Semi- Micro, and Cannon Fenske Opaque. To calculate C at test temperatures other than the calibration temperature for these viscometers, see ASTM D2515–66 (incorporated by reference, see § 571.5) or follow instructions given on the manufacturer’s certificate of calibra-tion.

(b) Average the four timed runs on the duplicate samples to determine the kinematic viscosities.

S6.3.7 Precision (at 95 percent con-fidence level).

(a) Repeatability. If results on dupli-cate samples by the same operator dif-fer by more than 1 percent of their mean, repeat the tests.

S6.4 pH value. Determine the pH value of a brake fluid by running one sample according to the following pro-cedure.

S6.4.1 Summary of the procedure.

Brake fluid is diluted with an equal volume of an ethanol-water solution.

The pH of the resultant mixture is measured with a prescribed pH meter assembly at 23 °C. (73.4 °F.).

S6.4.2 Apparatus. The pH assembly consists of the pH meter, glass elec-trode, and calomel electrode, as speci-fied in Appendices A1.1, A1.2, and A1.3 of ASTM D1121–67 (incorporated by ref-erence, see § 571.5). The glass electrode is a full range type (pH 0–14), with low sodium error.

S6.4.3 Reagents. Reagent grade chemicals conforming to the specifica-tions of the Committee on Analytical Reagents of the American Chemical Society.

(a) Distilled water. Distilled water (S7.1) shall be boiled for about 15 min-utes to remove carbon dioxide, and pro-tected with a soda-lime tube or its equivalent while cooling and in stor-age. (Take precautions to prevent con-tamination by the materials used for protection against carbon dioxide.) The

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00556 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31kp ay ne o n V

M O

F R

W

IN

w ith pH of the boiled distilled water shall be between 6.2 and 7.2 at 25 °C. (77 °F.).

(b) Standard buffer solutions. Prepare buffer solutions for calibrating the pH meter and electrode pair from salts sold specifically for use, either singly or in combination, as pH standards.

Dry salts for 1 hour at 110 °C. (230 °F.)

before use except for borax which shall be used as the decahydrate. Store solu-tions with pH less than 9.5 in bottles of chemically resistant glass or poly-ethylene. Store the alkaline phosphate solution in a glass bottle coated inside with paraffin. Do not use a standard with an age exceeding three months.

(1) Potassium hydrogen phthalate buffer solution (0.05 M, pH = 4.01 at 25 °C. (77 °F.)). Dissolve 10.21 g. of potas-sium hydrogen phthalate (KHC8 H4 O4) in distilled water. Dilute to 1 liter.

(2) Neutral phosphate buffer solution (0.025 M with respect to each phosphate salt, pH = 6.86 at 25 °C. (77 °F.)). Dis-solve 3.40 g. of potassium dihydrogen phosphate (KH2 PO4) and 3.55 g. of an-hydrous disodium hydrogen phosphate (Na2 HPO4) in distilled water.

(3) Borax buffer solution (0.01 M, pH =

9.18 at 25 °C. (77 °F.)). Dissolve 3.81 g. of disodium tetraborate decahydrate (Na2 B4 O7°10H2O) in distilled water, and di-lute to 1 liter. Stopper the bottle ex-cept when actually in use.

(4) Alkaline phosphate buffer solu-tion (0.01 M trisodium phosphate, pH =

11.72 at 25 °C. (77 °F.)). Dissolve 1.42 g.

of anhydrous disodium hydrogen phos-phate (Na2 HPO4) in 100 ml. of a 0.1 M carbonate-free solution of sodium hy-droxide. Dilute to 1 liter with distilled water.

(5) Potassium chloride electrolyte.

Prepare a saturated solution of potas-sium chloride (KCl) in distilled water.

(c) Ethanol-water mixture. To 80 parts by volume of ethanol (S7.3) add 20 parts by volume of distilled water. Adjust the pH of the mixture to 7 ±0.1 using 0.1 N sodium hydroxide (NaOH) solution. If more than 4 ml. of NaOH solution per liter of mixture is required for neutral-ization, discard the mixture.

S6.4.4 Preparation of electrode system.

(a) Maintenance of electrodes. Clean the glass electrode before using by im-mersing in cold chromic-acid cleaning solution. Drain the calomel electrode and fill with KCl electrolyte, keeping level above that of the mixture at all times. When not in use, immerse the lower halves of the electrodes in dis-tilled water, and do not immerse in the mixture for any appreciable period of time between determinations.

(b) Preparation of electrodes. Condition new glass electrodes and those that have been stored dry as recommended by the manufacturer. Before and after using, wipe the glass electrode thor-oughly with a clean cloth, or a soft ab-sorbent tissue, and rinse with distilled water. Before each pH determination, soak the prepared electrode in distilled water for at least 2 minutes. Imme-diately before use, remove any excess water from the tips of the electrode.

S6.4.5 Standardization of the pH as-sembly and testing of the electrodes. (a) Immediately before use, standardize the pH assembly with a standard buffer solution. Then use a second standard buffer solution to check the linearity of the response of the electrodes at dif-ferent pH values, and to detect a faulty glass electrode or incorrect tempera-ture compensation. The two buffer so-lutions bracket the anticipated pH value of the test brake fluid.

(b) Allow instrument to warm up, and adjust according to the manufac-turer’s instructions. Immerse the tips of the electrodes in a standard buffer solution and allow the temperature of the buffer solution and the electrodes to equalize. Set the temperature knob at the temperature of the buffer solu-tion. Adjust the standardization or asymmetry potential control until the meter registers a scale reading, in pH units, equal to the known pH of the standardizing buffer solution.

(c) Rinse the electrodes with distilled water and remove excess water from the tips. Immerse the electrodes in a second standard buffer solution. The reading of the meter shall agree with the known pH of the second standard buffer solution within ±0.05 unit with-out changing the setting of the stand-ardization of asymmetry potential con-trol.

(d) A faulty electrode is indicated by failure to obtain a correct value for the pH of the second standard buffer solu-tion after the meter has been standard-ized with the first.

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00557 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31kp ay ne o n V

M O

F R

W

IN

w ith

S6.4.6 Procedure. To 50 ±1 ml. of the test brake fluid add 50 ±1 ml. of the ethanol-water (S6.4.3(c)) and mix thor-oughly. Immerse the electrodes in the mixture. Allow the system to come to equilibrium, readjust the temperature compensation if necessary, and take the pH reading.

S6.5 Fluid stability. Evaluate the heat and chemical stability of a brake fluid by the following procedure, run-ning duplicate samples for each test and averaging the results.

S6.5.1 Summary of the procedure. The degradation of the brake fluid at ele-vated temperature, alone or in a mix-ture with a reference fluid, is evaluated by determining the change in boiling point after a period of heating under reflux conditions.

S6.5.2 Apparatus. Use the apparatus and preparation specified in S6.1.2 and S6.1.3.

S6.5.3 High temperature stability.

S6.5.3.1 Procedure. (a) Heat a new 60

±1 ml. sample of the brake fluid to 185° ±2 °C. (365° ±3.6 °F.). Hold at this tem-perature for 120 ±5 minutes. Bring to a reflux rate in excess of 1 drop per sec-ond within 5 minutes. The reflux rate should not exceed 5 drops per second at any time. Over the next 5 ±2 minutes adjust the heating rate to obtain an equilibrium reflux rate of 1 to 2 drops per second. Maintain this rate for an additional 2 minutes, taking four tem-perature readings at 30–second inter-vals. Average these as the observed ERBP. If no reflux is evident when the fluid temperature reaches 260 °C. (500 °F), discontinue heating and report ERBP as in excess of 260 °C. (500 °F.).

S6.5.3.2 Calculation. Correct the ob-served ERBP for thermometer and bar-ometric pressure factors according to S6.1.5 (a) and (b). Average the corrected ERBP’s of the duplicate samples. The difference between this average and the original ERBP obtained in S6.1 is the change in ERBP of the fluid.

S6.5.4 Chemical stability.

S6.5.4.1 Materials. SAE RM–66–04

Compatibility Fluid as described in ap-pendix B of SAE Standard J1703 JAN95 (incorporated by reference, see § 571.5).

S6.5.4.2 Procedure. (a) Mix 30 ±1 ml.

of the brake fluid with 30 ±1 ml. of SAE RM–66–04 Compatibility Fluid in a boil-ing point flask (S6.1.2(a)). Determine the initial ERBP of the mixture by ap-plying heat to the flask so that the fluid is refluxing in 10 ±2 minutes at a rate in excess of 1 drop per second, but not more than 5 drops per second. Note the maximum fluid temperature ob-served during the first minute after the fluid begins refluxing at a rate in ex-cess of 1 drop per second. Over the next 15 ±1 minutes, adjust and maintain the reflux rate at 1 to 2 drops per second.

Maintain this rate for an additional 2 minutes, recording the average value of four temperature readings taken at 30 second intervals as the final ERBP.

(b) Thermometer and barometric cor-rections are not required.

S6.5.4.3 Calculation. The difference between the initial ERBP and the final average temperature is the change in temperature of the refluxing mixture.

Average the results of the duplicates to the nearest 0.5 °C (1.0 °F).

S6.6 Corrosion. Evaluate the corro-siveness of a brake fluid by running du-plicate samples according to the fol-lowing procedure.

S6.6.1 Summary of the procedure. Six specified metal corrosion test strips are polished, cleaned, and weighed, then assembled as described. Assembly is placed on a standard wheel cylinder cup in a corrosion test jar, immersed in the water-wet brake fluid, capped and placed in an oven at 100 °C. (212 °F.) for 120 hours. Upon removal and cooling, the strips, fluid, and cups are examined and tested.

S6.6.2 Equipment. (a) Balance. An an-alytical balance having a minimum ca-pacity of 50 grams and capable of weighing to the nearest 0.1 mg.

(b) Desiccators. Desiccators con-taining silica gel or other suitable des-iccant.

(c) Oven. Gravity convection oven ca-pable of maintaining the desired set point within 2 °C. (3.6 °F.).

(d) Micrometer. A machinist’s mi-crometer 25 to 50 mm. (1 to 2 inches) capacity, or an optical comparator, ca-pable of measuring the diameter of the SBR wheel cylinder (WC) cups to the nearest 0.02 mm. (0.001 inch).

S6.6.3 Materials. (a) Corrosion test strips. Two sets of strips from each of the metals listed in Appendix C of SAE Standard J1703b (1970) (incorporated by reference, see § 571.5). Each strip shall

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00558 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31kp ay ne o n V

M O

F R

W

IN

w ith be approximately 8 cm. long, 1.3 cm.

wide, not more than 0.6 cm. thick, and have a surface area of 25 ±5 sq. cm. and a hole 4 to 5 mm. (0.16 to 0.20 inch) in diameter on the centerline about 6 mm.

from one end. The hole shall be clean and free from burrs. Tinned iron strips shall be unused. Other strips, if used, shall not be employed if they cannot be polished to a high finish.

(b) SBR cups. Two unused standard SAE SBR wheel cylinder (WC) cups, as specified in S7.6.

(c) Corrosion test jars and lids. Two screw-top straight-sided round glass jars, each having a capacity of approxi-mately 475 ml. and inner dimensions of approximately 100 mm. in height and 75

mm. in diameter, and a tinned steel lid (no insert or organic coating) vented with a hole 0.8 ±0.1 mm. (0.031 ±0.004 inch) in diameter (No. 68 drill).

(d) Machine screws and nuts. Clean, rust and oil-free, uncoated mild steel round or fillister head machine screws, size 6 or 8–32 UNC-Class 2A, five-eighths or three-fourths inch long (or equivalent metric sizes), and matching uncoated nuts.

(e) Supplies for polishing strips. Water-proof silicon carbide paper, grit No.

320A and grit 1200; lint-free polishing cloth.

(f) Distilled water as specified in S7.1.

(g) Ethanol as specified in S7.3.

(h) Isopropanol as specified in S7.7.

S6.6.4 Preparation.

(a) Corrosion test strips. Except for the tinned iron strips, abrade corrosion test strips on all surface areas with 320A silicon carbide paper wet with ethanol (isopropanol when testing DOT 5 SBBF fluids) until all surface scratches, cuts and pits visible to an observer having corrected visual acuity of 20/40 (Snellen ratio) at a distance of 300 mm (11.8 inches) are removed. Use a new piece of paper for each different type of metal. Except for the tinned iron strips, further abrade the test strips on all surface areas with 1200 sil-icon carbide paper wet with ethanol (isopropanol when testing DOT 5 SBBF fluids), again using a new piece of paper for each different type of metal.

Handle the strips with forceps after polishing. Weigh and record the weight of each strip to the nearest 0.1 mg. As-semble the strips on a clean dry ma-chine screw, with matching plain nut, in the order of tinned iron, steel, alu-minum, cast iron, brass, and copper.

Bend the strips, other than the cast iron, so that there is a separation of 3 ±1⁄2 mm. (1⁄8 ±1⁄64 inch) between adjacent strips for a distance of about 5 cm. (2 inches) from the free end of the strips.

(See Figure 4.) Tighten the screw on each test strip assembly so that the strips are in electrolytic contact, and can be lifted by either of the outer strips (tinned iron or copper) without any of the strips moving relative to the others when held horizontally. Im-merse the strip assemblies in 90 per-cent ethyl alcohol. Dry with dried fil-tered compressed air, then desiccate at least 1 hour before use.

FIG. 4—CORROSION STRIP ASSEMBLY

(b) SBR WC cups. Measure the base diameters of the two standard SBR cups, using an optical comparator or micrometer, to the nearest 0.02 mm.

(0.001 inch) along the centerline of the SAE and rubber-type identifications and at right angles to this centerline.

Take the measurements at least 0.4

mm. (0.015 inch) above the bottom edge and parallel to the base of the cup. Dis-card any cup if the two measured diam-eters differ by more than 0.08 mm.

(0.003 inch). Average the two readings on each cup. Determine the hardness of the cups according to S7.4.

S6.6.5 Procedure. Rinse the cups in ethanol (isopropanol when testing DOT 5 SBBF fluids) for not more than 30 seconds and wipe dry with a clean lint-free cloth. Place one cup with lip edge

VerDate Sep<11>2014 12:57 Jan 31, 2019 Jkt 244230 PO 00000 Frm 00559 Fmt 8010 Sfmt 8010 Q:\49\49V6.TXT PC31 E C

A

U

.0 kp ay ne o n V

M O

F R

W

IN

w ith facing up, in each jar. Insert a metal strip assembly inside each cup with the fastened end down and the free end ex-tending upward. (See Figure 5.) When testing brake fluids, except DOT 5 SBBF, mix 760 ml. of brake fluid with 40 ml. of distilled water. When testing DOT 5 SBBF’s, humidify 800 ml. of brake fluid in accordance with S6.2, eliminating determination of the ERBP. Using this water-wet mixture, cover each strip assembly to a min-imum depth of 10 mm. above the tops of the strips. Tighten the lids and place the jars for 120 ±2 hours in an oven maintained at 100° ±2 °C. (212° ±3.6 °F.).

Allow the jars to cool at 23° ±5 °C. (73.4° ±9 °F.) for 60 to 90 minutes. Imme-diately remove the strips from the jars using forceps, agitating the strip as-sembly in the fluid to remove loose ad-hering sediment. Examine the test strips and jars for adhering crystalline deposits. Disassemble the metal strips, and remove adhering fluid by flushing with water; clean each strip by wiping with a clean cloth wetted with ethanol (isopropanol when testing DOT 5 fluids). Examine the strips for evidence of corrosion and pitting. Disregard staining or discoloration. Place the strips in a desiccator containing silica gel or other suitable desiccant, main-tained at 23° ±5 °C. (73.4° ±9 °F.), for at least 1 hour. Weigh each strip to the nearest 0.1 mg. Determine the change in weight of each metal strip. Average the results for the two strips of each type of metal. Immediately following the cooling period, remove the cups from the jars with forceps. Remove loose adhering sediment by agitation of the cups in the mixture. Rinse the cups in ethanol (isopropanol when testing DOT 5 fluids) and air-dry. Examine the cups for evidence of sloughing, blisters, and other forms of disintegration.

Measure the base diameter and hard-ness of each cup within 15 minutes after removal from the mixture. Exam-ine the mixture for gelling. Agitate the mixture to suspend and uniformly dis-perse sediment. From each jar, transfer a 100 ml. portion of the mixture to an ASTM cone-shaped centrifuge tube. De-termine the percent sediment after centrifuging as described in S7.5. Meas-ure the pH value of the corrosion text fluid according to S6.4.6. Measure the pH value of the test mixture according to S6.4.6.

FIG. 5—CORROSION TEST APPARATUS

S6.6.6 Calculation. (a) Measure the area of each type of test strip to the nearest square centimeter.