(a) DOT 3: 205°C (401°F),
(b) DOT 4: 230°C (446°F),
(c) DOT 5: 260°C (500°F).

(a) DOT 3: 140°C (284°F),
(b) DOT 4: 155°C (311°F),
(c) DOT 5: 1 180°C (356°F).

(a) DOT 3: 1,500 mm²/s at -40°C (-40°F),
(b) DOT 4: 1,800 mm²/s at -40°C (-40°F),
(c) DOT 5: 900 mm²/s at -40°C (-40°F).

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

(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, sedimentation 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 evidenced 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).

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

(b) Upon inversion of the sample bottle, 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.

(a) At low temperature. When brake fluid is tested according to S6.9.3(a):

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

(a) At low temperature. When brake fluid is tested according to S6.10.3(a), the test specimen shall show no sludging, sedimentation, or crystallization. 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):

(a) The metal test strips outside the areas in contact with the tinfoil shall not show pitting or etching to an extent 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 mass weight by more than 0.05 mg/cm²; and

(d) The cast iron strips shall not change in mass weight by more than 0.3 mg/cm².

(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 disintegration as evidenced by stickiness, blisters, or sloughing.

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

(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 appearance;

(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 mL;

(h) The cylinder pistons shall not freeze or function improperly throughout the test;

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

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

(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 deposits that are abrasive or that cannot be removed when rubbed moderately with a nonabrasive cloth wetted with ethanol.

DOT 3, DOT 4, and DOT 5.1 non-SBBF — colorless to amber.
DOT 5 SBBF — purple.
Hydraulic system mineral oil — green.

(a) Flask. (See Figure 2) A 100-mL round-bottom, short-neck, heat-resistant 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 mm, which centers the thermometer 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) Thermometers. Standardized calibrated partial immersion (76 mm), solid stem, thermometers conforming to the requirements for an ASTM 2C or 2F, and an ASTM 3C or 3F thermometer; and

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

(a) Thoroughly clean and dry all glassware.

(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 rheostat-controlled heater, center a standard porcelain or hard asbestos refractory, 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. Connect the cooling water inlet and outlet tubes to the condenser. Turn on the cooling water. The water supply temperature shall not exceed 28°C (82.4°F) and the temperature rise through the condenser shall not exceed 2°C (3.6°F).

(a) Thermometer inaccuracy. Correct the observed ERBP by applying any correction factor obtained in standardizing the thermometer.

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

(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 entire test, averaging the four corrected observed values to determine the original ERBP.

(a) Glass jars. Four SAE RM-49 corrosion 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) Desiccators and covers. Two bowl-form glass desiccators, 250-mm inside diameter, having matching tubulated covers fitted with No. 8 rubber stoppers; and

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

(a) Distilled water, see S7.1.

(b) SAE TEGME referee material.

(a) Viscometers. Calibrated glass capillary-type viscometers, ASTM D2515-66, Standard Specification for Kinematic Glass Viscometers,¹ measuring viscosity within the precision limits of S6.3.7 S6.4.7. Use suspended level viscometers for viscosity measurements at low temperatures. Use Cannon-Fenske Routine or other modified Ostwald viscometers at ambient temperatures 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 liquid bath of sufficient depth such that at no time during the measurement will any portion of the sample in the 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 sufficient to meet the temperature control 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 Thermometers covering the range of test temperatures indicated in Table IV and conforming to ASTM E1-68, Specifications for ASTM Thermometers,¹ and in the IP requirements for IP Standard Thermometers. Standardize before use (see S6.3.3(b)). Use two standardized thermometers in the bath.

(a) Viscometers. Use viscometers calibrated in accordance with Appendix 1 of ASTM D445-65, Viscosity of Transparent and Opaque Liquids (Kinematic and Dynamic Viscosities).¹ The calibration constant, C, is dependent upon the gravitational acceleration at the place of calibration. This must, therefore, be supplied 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 constant as follows:

where the subscripts 1 and 2 indicate, respectively, the standardization laboratory 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. Kinematic Viscosity Test Thermometers shall be standardized at "total immersion." The ice point of standardized thermometers shall be determined before use and the official corrections shall be adjusted to conform to the changes in ice points. (See ASTM E77-66, Verification and Calibration of Liquid-in-Glass Thermometers.)¹

(c) Timers. Time signals are broadcast by the National Institute of Standards and Technology National Bureau of Standards, Station WWV, Fort Collins, Colorado, Washington, DC at 2.5, 5, 10, 15, 20, 25, 30, and 35 Mc/sec (MHz). Time signals are also broadcast by Station CHU from Ottawa, Canada, at 3.330, 7.335, and 14.670 Mc/sec, and Station MSF at Rugby, United Kingdom, at 2.5, 5, and 10 Mc/sec.

(a) Set and maintain the bath at the appropriate test temperature (see S5.1.3) within the limits specified in S6.3.2(c). Apply the necessary corrections, if any, to all thermometer readings.

(b) Select a clean, dry, calibrated viscometer giving a flow time not less than its specified minimum, or 200 seconds, 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 contamination by dirt and moisture during filling and measurements.

(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 temperature.

(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 temperature 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 minimum specified for the viscometer, or 200 seconds, whichever is greater, repeat using a viscometer with a capillary 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.

(a) Periodically clean the instrument with chromic acid to remove organic deposits. 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.

(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, Kinematic Glass Viscometers,¹ or follow instructions given on the manufacturer's certificate of calibration.

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

(a) Repeatability. If results on duplicate samples by the same operator differ by more than 1 percent of their mean, repeat the tests.

(a) Distilled water. Distilled water (S7.1) shall be boiled for about 15 minutes to remove carbon dioxide and protected with a soda-lime tube or its equivalent while cooling and in storage. (Take precautions to prevent contamination by the materials used for protection against carbon dioxide.) The 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 solutions with pH less than 9.5 in bottles of chemically resistant glass or polyethylene. Store the alkaline phosphate solution in a glass bottle coated inside with paraffin. Do not use a standard with an age exceeding three months.

(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 neutralization, discard the mixture.

(a) Maintenance of electrodes. Clean the glass electrode before using by immersing 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 distilled 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 thoroughly with a clean cloth, or a soft absorbent tissue, and rinse with distilled water. Before each pH determination, soak the prepared electrode in distilled water for at least 2 minutes. Immediately before use, remove any excess water from the tips of the electrode.

(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 different pH values, and to detect a faulty glass electrode or incorrect temperature compensation. The two buffer solutions bracket the anticipated pH value of the test brake fluid.

(b) Allow instrument to warm up and adjust according to the manufacturer'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 solution. Adjust the standardization of 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 without changing the setting of the standardization of asymmetry potential control.

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

(a) Heat a new 60 ± 1 mL sample of the brake fluid to 185 ± 2°C (365 ± 3.6°F). Hold at this temperature for 120 ± 5 minutes. Bring to a reflux rate in excess of 1 drop per second 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 temperature readings at 30-second intervals. 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).

(a) Mix 30 ± 1 mL of the brake fluid with 30 ± 1 mL of SAE RM-66-04 Compatibility Fluid in a boiling point flask (S6.1.2(a)). Determine the initial ERBP of the mixture by applying 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 observed during the first minute after the fluid begins refluxing at a rate in excess 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 corrections are not required.

(a) Balance. An analytical balance having a minimum capacity of 50 g and capable of weighing to the nearest 0.1 mg.

(b) Desiccators. Desiccators containing silica gel or other suitable desiccant.

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

(d) Micrometer. A machinist's micrometer 25 to 50 mm (1 to 2 inches) capacity, or an optical comparator, capable of measuring the diameter of the SBR wheel cylinder (WC) cups to the nearest 0.02 mm (0.001 inch).

(a) Corrosion test strips. Two sets of strips from each of the metals listed in Appendix C of SAE Standard J1703b, Motor Vehicle Brake Fluid, July 1970. Each strip shall be approximately 8 cm long, 1.3 cm wide, not more than 0.6 cm thick, and have a surface area of 25 ± 5 square 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 approximately 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. Waterproof silicon carbide paper, grit No. 320 and grit No. 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.

(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 silicon 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. Wash all strips, including the tinned iron and the assembly hardware, with ethanol (isopropanol when testing DOT 5 SBBF fluids); dry the strips and assembly hardware with a clean lint-free cloth or use filtered compressed air and place the strips and hardware in a desiccator containing silica gel or other suitable desiccant and maintained at 23 ± 5°C (73.4 ± 9°F), for at least 1 hour. Handle the strips with forceps after polishing. Weigh and record the mass weight of each strip to the nearest 0.1 mg. Assemble the strips on a clean dry machine screw, with matching plain nut, in the order of tinned iron, steel, aluminum, cast iron, brass, and copper. Bend the strips, other than the cast iron, so that there is a separation of 3 ± 0.5 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. Immerse the strip assemblies in 90 percent ethyl alcohol. Dry with dried filtered compressed air, then desiccate at least 1 hour before use.

(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. Discard any cup if the two measured diameters 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.

(a) Measure the area of each type of test strip to the nearest square centimeter. Divide the average change in mass for each type by the area of that type.

(b) Note other data and evaluations indicating compliance with S5.1.6. In the event of a marginal pass on inspection by attributes, or of a failure in one of the duplicates, run another set of duplicate samples. Both repeat samples shall meet all requirements of S5.1.6.

(a) Oil sample bottles. Two clear, flint glass 118-mL (4-ounce) bottles made especially for sampling oil and other liquids, with a capacity of approximately 125 mL, an outside diameter of 37 ± 0.05 mm, and an overall height of 165 ± 2.5 mm.

(b) Cold chamber. An air bath cold chamber capable of maintaining storage temperatures down to -55°C (-67°F) with an accuracy of ± 2°C (3.6°F).

(c) Timing device. A timing device in accordance with S6.3.2(e).

(a) Place 100 ± 1 mL of brake fluid at room temperature in an oil sample bottle. Stopper the bottle with an unused cork and place in the cold chamber at the higher storage temperature specified in Table II (S5.1.7(c)). After 144 ± 4 hours, remove the bottle from the chamber, quickly wipe it with a clean, lint-free cloth saturated with ethanol (isopropanol when testing DOT 5 fluids) or acetone. Examine the fluid for evidence of sludging, sedimentation, crystallization, or stratification. Invert the bottle and determine the number of seconds required for the air bubble to travel to the top of the fluid. Let sample warm to room temperature and examine.

(b) Repeat S6.7.3(a), substituting the lower cold chamber temperature specified in Table II and a storage period of 6 hours ± 12 minutes.

Note: Test specimens from either storage temperature may be used for the other only after warming up to room temperature.

(a) Centrifuge tube. See S7.5.1(a).

(b) Centrifuge. See S7.5.1(b).

(c) Cold chamber. See S6.7.2(b).

(d) Oven. Gravity or forced convection oven.

(e) Timing device. See S6.3.2(e).

(a) At low temperature. Humidify 100 ± 1 mL of DOT 5 SBBF brake fluid in accordance with S6.2, eliminating determination of the ERBP. When testing brake fluids, except DOT 5 SBBF, mix 3.5 ± 0.1 mL of distilled water with 100 ± 1 mL of the brake fluid; pour into a centrifuge tube. Stopper the tube with a clean cork and place in the cold chamber maintained at -40 ± 2°C (-40 ± 3.6°F). After 120 hours ± 2 hours, remove the tube, quickly wipe with clean lint-free cloth saturated with ethanol or acetone, and examine the fluid for evidence of sludging, sedimentation, crystallization, or stratification. Invert the tube and determine the number of seconds required for the air bubble to travel to the top of the fluid. (The air bubble is considered to have reached the top of the fluid when the top of the bubble reaches the 2-mL graduation of the centrifuge tube.) If the wet fluid has become cloudy, warm to 23 ± 5°C (73.4 ± 9°F) and note appearance and fluidity.

(b) At 60°C (140°F). Place tube and brake fluid from S6.9.3(a) in an oven maintained at 60 ± 2°C (140 ± 3.6°F) for 24 ± 2 hours. Remove the tube and immediately examine the contents for evidence of stratification. Determine the percent sediment by centrifuging as described in S7.5.

(a) Centrifuge tube. See S7.5.1(a).

(b) Centrifuge. See S7.5.1(b).

(c) Cold Chamber. See S6.7.2(b).

(d) Oven. See S6.9.2(d).

(e) SAE RM-66-04 Compatibility Fluid. As described in Appendix B of SAE Standard J1703 JAN 1995, Motor Vehicle Brake Fluid. [SENTENCE DELETED]

(a) At low temperature. Mix 50 ± 0.5 mL of brake fluid with 50 ± 0.5 mL of SAE RM-66-04 Compatibility Fluid. Pour this mixture into a centrifuge tube and stopper with a clean dry cork. Place tube in the cold chamber maintained at -40 ± 2°C (-40 ± 4°F). After 24 ± 2 hours, remove tube, quickly wipe with a clean lint-free cloth saturated with ethanol (isopropanol when testing DOT 5 fluids) or acetone. Examine the test specimen for evidence of sludging, sedimentation, or crystallization. Test fluids, except DOT 5 SBBF, shall be examined for stratification.

(b) At 60°C (140°F). Place tube and test fluid from S6.10.3(a) for 24 ± 2 hours in an oven maintained at 60 ± 2°C (140 ± 3.6°F). Remove the tube and immediately examine the contents of the test mixtures, except DOT 5 SBBFs, for evidence of stratification. Determine percent sediment by centrifuging as described in S7.5.

(a) Balance. See S6.6.2(a).

(b) Desiccators. See S6.6.2(b).

(c) Oven. See S6.6.2(c).

(d) Three glass test tubes approximately 22 mm outside diameter by 175 mm in length.

(a) Benzoyl peroxide, reagent grade, 96 percent. (Benzoyl peroxide that is brownish, or dusty, or has less than 90 percent purity, must be discarded.) Reagent strength may be evaluated by ASTM E298-68, Standard Methods for Assay of Organic Peroxides.¹

(b) Corrosion test strips. Two sets of cast iron and aluminum metal test strips as described in Appendix C of SAE Standard J1703b.

(c) Tinfoil. Four unused pieces of tinfoil approximately 12 mm (1/2 inch) square and between 0.02 and 0.06 mm (0.0008 and 0.0024 inch) in thickness. The foil shall be at least 99.9 percent tin and contain not more than 0.025 percent lead.

(d) SBR cups. Two unused, approximately one-eighth sections of a standard SAE SBR WC cup (as described in S7.6).

(e) Machine screws and nuts. Two clean oil-free, No. 6 or 8-32 x 3/8 - or 1/2-inch long (or equivalent metric size), round or fillister head, uncoated mild steel machine screws, with matching plain nuts.

(a) Corrosion test strips. Prepare two sets of aluminum and cast iron test strips according to S6.6.4(a), except for assembly. Weigh each strip to the nearest 0.1 mg and assemble a strip of each metal on a machine screw, separating the strips at each end with a piece of tinfoil. Tighten the nut enough to hold both pieces of foil firmly in place.

(b) Test mixture. Place 30 ± 1 mL of the brake fluid under test in a 22 by 175 mm test tube. For all fluids except DOT 5 SBBF fluids, add 0.060 ± 0.002 grams of benzoyl peroxide and 1.50 ± 0.05 mL of distilled water. For DOT 5 SBBF fluids, use test fluid humidified in accordance with S6.2, and add only the benzoyl peroxide. Stopper the tube loosely with a clean dry cork, shake, and place in an oven for 2 hours at 70 ± 2°C (158 ± 3.6°F). Shake every 15 minutes to effect solution of the peroxide, but do not wet cork. Remove the tube from the oven and allow to cool to 23 ± 5°C (73.4 ± 9°F). Begin testing according to S6.11.5 not later than 24 hours after removal of tube from oven.

(a) Oven. See S6.6.2(c).

(b) Glass jars and lids. Two screw-top, straight-sided round glass jars, each having a capacity of approximately 250 mL and inner dimensions of approximately 125 mm in height and 50 mm in diameter, and a tinned steel lid (no insert or organic coating).

(c) SBR cups. See S7.6.

(a) Calculate the change in base diameter for each cup. If the two values, at each temperature, do not differ by more than 0.10 mm (0.004 inch), average them to the nearest 0.02 mm (0.001 inch). If the two values differ by more than 0.10 mm, repeat the test at the appropriate temperature and average the four values as the change in base diameter.

(b) Calculate the change in hardness for each cup. The average of the two values for each pair is the change in hardness.

(c) Note disintegration as evidenced by stickiness, blisters, or sloughing.

(a) Brake assemblies. With the drum and shoe apparatus: three drum and shoe assembly units (SAE RM-29a) consisting of three forward brake shoes and three reverse brake shoes with linings and three front wheel brake drum assemblies with assembly component parts. With stroking fixture type apparatus: three fixture units including appropriate adapter mounting plates to hold brake wheel cylinder assemblies.

(b) Braking pressure actuation mechanism. An actuating mechanism for applying a force to the master cylinder pushrod without side thrust. The amount of force applied by the actuating mechanism shall be adjustable and capable of applying sufficient thrust to the master cylinder to create a pressure of at least 6,895 kPa (1,000 psi) in the simulated brake system. A hydraulic gage or pressure recorder, having a range of at least 0 to 6,895 kPa (0 to 1,000 psi), shall be installed between the master cylinder and the brake assemblies and shall be provided with a shutoff valve and with a bleeding valve for removing air from the connecting tubing. The actuating mechanism shall be designed to permit adjustable stroking rates of approximately 1,000 strokes per hour. Use a mechanical or electrical counter to record the total number of strokes.

(c) Heated air bath cabinet. An insulated cabinet or oven having sufficient capacity to house the three mounted brake assemblies or stroking fixture assemblies, master cylinder, and necessary connections. A thermostatically controlled heating system is required to maintain a temperature of 70 ± 5°C (158 ± 9°F) or 120 ± 5°C (248 ± 9°F). Heaters shall be shielded to prevent direct radiation to wheel or master cylinder.

(d) Master cylinder (MC) assembly (SAE RM-15a). One cast-iron housing hydraulic brake system cylinder having a diameter of approximately 28 mm (1 1/8 inch) and fitted for a filler cap and standpipe (see S6.13.2(e)). The MC piston shall be made from SAE CA 360 copperbase alloy (half hard). A new MC assembly is required for each test.

(e) Filler cap and standpipe. MC filler cap provided with a glass or uncoated steel standpipe. Standpipe must provide adequate volume for thermal expansion, yet permit measurement and adjustment of the fluid level in the system to ± 3 mL. Cap and standpipe may be cleaned and reused.

(f) Wheel cylinder (WC) assemblies (SAE RM-14a). Three unused cast-iron housing straight bore hydraulic brake WC assemblies having diameters of approximately 28 mm (1 1/8 inch) for each test. Pistons shall be made from unanodized SAE AA 2024 aluminum alloy.

(g) Micrometer. Same as S6.6.2(d).

(a) Standard SBR brake cups. Six standard SAE SBR wheel cylinder test cups, one primary MC test cup, and one secondary MC test cup, all as described in S7.6, for each test.

(b) Steel tubing. Double-wall steel tubing meeting SAE specification J527. A complete replacement of tubing is essential when visual inspection indicates any corrosion or deposits on inner surface of tubing. Tubing from master cylinder to one wheel cylinder shall be replaced for each test (minimum length 0.9 m). Uniformity in tubing size is required between master cylinder and wheel cylinder. The standard master cylinder has two outlets for tubing, both of which must be used.

(a) Wheel cylinder assemblies. Use unused wheel cylinder assemblies. Disassemble cylinders and discard cups. Clean all metal parts with ethanol (isopropanol when testing DOT 5 fluids). Inspect the working surfaces of all metal parts for scoring, galling, or pitting and cylinder bore roughness, and discard all defective parts. Remove any stains on cylinder walls with crocus cloth and ethanol (isopropanol when testing DOT 5 fluids). If stains cannot be removed, discard the cylinder. Measure the internal diameter of each cylinder at a location approximately 19 mm (0.75 inch) from each end of the cylinder bore, taking measurements in line with the hydraulic inlet opening and at right angles to this centerline. Discard the cylinder if any of these four readings exceeds the maximum or minimum limits of 28.66 to 28.60 mm (1.128 to 1.126 inch). Measure the outside diameter of each piston at two points approximately 90° apart. Discard any piston if either reading exceeds the maximum or minimum limits of 28.55 to 28.52 mm (1.124 to 1.123 inch). Select parts to insure that the clearance between each piston and mating cylinder is within 0.08 to 0.13 mm (0.003 to 0.005 inch). Use unused SBR cups. To remove dirt and debris, rinse the cups in 90 percent ethyl alcohol for not more than 30 seconds and wipe dry with a clean lint-free cloth. Discard any cups showing defects such as cuts, molding flaws, or blisters. Measure the lip and base diameters of all cups with 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. Determine base diameter measurements at least 0.4 mm (0.015 inch) above the bottom edge and parallel to the base of the cup. Discard any cup if the two measured lip or base diameters differ by more than 0.08 mm (0.003 inch). Average the lip and base diameters of each cup. Determine the hardness of all cups according to S7.4. Dip the rubber and metal parts of wheel cylinders, except housing and rubber boots, in the fluid to be tested and install them in accordance with the manufacturer's instructions. Manually stroke the cylinders to insure that they operate easily. Install cylinders in the simulated brake system.

(b) Master cylinder assembly. Use an unused master cylinder and unused standard SBR primary and secondary MC cups which have been inspected, measured, and cleaned in the manner specified in S6.13.4(a), omitting hardness of the secondary MC cup. However, prior to determining the lip and base diameters of the secondary cup, dip the cup in test brake fluid, assemble on the MC piston, and maintain the assembly in a vertical position at 23 ± 5°C (73.4 ± 9°F) for at least 12 hours. Inspect the relief and supply ports of the master cylinder; discard the cylinder if ports have burrs or wire edges. Measure the internal diameter of the cylinder at two locations [approximately midway between the relief and supply ports and approximately 19 mm (0.75 inch) beyond the relief port toward the bottom or discharge end of the bore], taking measurements at each location on the vertical and horizontal centerline of the bore. Discard the cylinder if any reading exceeds the maximum or minimum limits of 28.65 to 28.57 mm (1.128 to 1.125 inch). Measure the outside diameter of each end of the master cylinder piston at two points approximately 90° apart. Discard the piston if any of these four readings exceed the maximum or minimum limits of 28.55 to 28.52 mm (1.124 to 1.123 inch). Dip the rubber and metal parts of the master cylinder, except the housing and push rod-boot assembly, in the brake fluid and install in accordance with manufacturer's instructions. Manually stroke the master cylinder to insure that it operates easily. Install the master cylinder in the simulated brake system.

(c) Assembly and adjustment of test apparatus

(a) Calculate the changes in diameters of cylinders and pistons (see S5.1.13(b)).

(b) Calculate the average decrease in hardness of the seven cups tested, as well as the individual values (see S5.1.13(c)).

(c) Calculate the increases in base diameters of the eight cups (see S5.1.13(e)).

(d) Calculate the lip diameter interference set for each of the eight cups by the following formula and average the eight values (see S5.1.13(f)).

where:
D₁ = Original lip diameter
D₂ = Final lip diameter
D₃ = Original cylinder bore diameter

(a) Anvil. A rubber anvil having a flat circular top 20 ± 1 mm (13/16 ± 1/16 inch) in diameter, a thickness of at least 9 mm (3/8 inch), and a hardness within 5 IRHDs of the SBR test cup.

(b) Hardness tester. A hardness tester meeting the requirements for the standard instrument as described in ASTM D1415-68, Standard Method of Test for International Hardness of Vulcanized Natural and Synthetic Rubbers,¹ and graduated directly in IRHD units.

(a) Centrifuge tubes. Cone-shaped centrifuge tubes conforming to the dimensions given in Figure 6 and made of thoroughly annealed glass. The graduations shall be numbered as shown in Figure 6 and shall be clear and distinct. Scale-error tolerances and smallest graduations between various calibration marks are given in Table V and apply to calibrations made with air-free water at 20°C (68°F).

b) Centrifuge. A centrifuge capable of whirling two or more filled centrifuge tubes at a speed which can be controlled to give a relative centrifugal force (r.c.f.) between 600 and 700 at the tip of the tubes. The revolving head, trunnion rings, and trunnion cups, including the rubber cushion, shall withstand the maximum centrifugal force capable of being delivered by the power source. The trunnion cups and cushions shall firmly support the tubes when the centrifuge is in motion. Calculate the speed of the rotating head using this equation: