Non-Tariff Barriers

Non-Tariff Measure

NTM classification

B82: Testing requirement 

Date when the measure came into force

17 July 1975 

Publication where the measure is specified

Government Notice 128 (Government Gazette 4562) Of 17 January 1975 

Regulation where the measure is specified

Compulsory Specification For Hydraulic Brake And Clutch Fluid 

Country/Region applying the measure

South Africa 

The rationale of the measure

This specification covers fluid of the non-petroleum and the non-silicone types suitable for use in automotive
hydraulic brake and clutch systems. 

Coded list of objectives

X: For purposes n.e.s. 

Description of the measure

4. METHODS OF TEST.

4.1 EQUILIBRIUM REFLUX BOILING POINT AT
A PRESSURE OF 101. 325 kPa.
4.1.1 Apparatus (see Fig. 1 and 2).

(a) flask. — A 100 ml round-bottomed flask of heat resistant glass with a short neck having a 19/38 standard- taper, female ground-glass joint, and a 10 mm outside diameter side tube which enters the flask at such an angle as to permit the end of die thermometer bulb to be directly centred in the flask 6.5 mm from die bottom.

(b) Condenser. — A reflux, glass tube condenser of the water-cooled type having a jacket 200 mm in length. The bottom end of the condenser shall have a 19/38 standard- taper, drip-tip, and a male ground-glass joint.
(c) Boiling stones. — Silicone carbide grains of No. 8 grit.
(d) Thermometer.— A thermometer having a range of
— 5 to 300 °C and accurately calibrated for 7,62 cm immersion.

(c) Neat source. — A means of heating that will provide the healing and reflux rates specified in 4.1.2.

4.1.2 Procedure. — Place 60±1 ml of the fluid together with three silicone carbide grains in the flask, attach the condenser and insert the thermometer through the side tube so that its end is 6,5 mm from the centre bottom of the flask. Seal the thermometer to the side tube with a short length of rubber tubing. Mount the flask, and turn on the condenser water. The water supply temperature shall be not more than 28 °C and the temperature rise through the condenser shall be not more than 2 °C.
Apply heat at such a rate that the fluid is refluxing in 10+/-2 min at a rate of 1 to 5 drops per second. During the next 5±2 min period by adjusting the heat input, ensure that the rate of reflux is I to 2 drops of equilibrium reflux per second. Maintain the specified reflux rate for an additional 2 min and then read the temperature and record the barometric pressure. The temperature reading should be the average of four readings taken at 30 s intervals.
4.1.3 Recording. — Correct the temperature for thermometer error and for difference in atmospheric pressure between that recorded and 101,325 kPa by applying the appropriate correction given in Table 2. Record the corrected temperature rounded off to the nearest 0,5 °C as the equilibrium reflux boiling point at a pressure of
101,325 kPa.

4.2 FLUID STABILITY.
4.2.1 Stability at high temperature.
4.2.1.1 Apparatus.— As described in 4.1
4.2.1.2 Procedure. — Heat a new 60 ±1 ml sample of the original test fluid to a temperature of 185±2 °C by the procedure specified in 4.1. Maintain it at that temperature for 120±5 min and then determine the equilibrium reflux boiling point again by the procedure described in 4.1.
4.2.1.3 Boiling point change. — Take as the change in the boiling point the difference between the two corrected equilibrium reflux boiling points.
4.2.2 Chemical stability.
4.2.2.1 Apparatus. — As described in 4.1.
4.2.2.2 Procedure.— Mix 30±ml of the fluid with 30±1 ml of standard compatibility fluid. Determine the equilibrium reflux boiling point of this fluid mixture by the procedure specified in 4.1, applying heat to the flask at such a rate that the fluid is refluxing in 10±2 min at a rate of one to five drops per second. Record the maximum fluid temperature observed during the first minute after the fluid begins to reflux at the specified rate. Over the next 15±1 min, adjust and maintain the rate of reflux to one to two drops per second. Maintain a constant equilibrium reflux rate of one to two drops per second for an additional 2 min. Record the average of four
temperature readings taken at 30 s intervals as the final equilibrium reflux boiling point.
4.2.2.3 Change in temperature. — Take as the change in temperature of the refluxing mixture the difference between the two corrected equilibrium reflux boiling points.

4.3 WET EQUILIBRIUM REFLUX BOILING POINT AT A PRESSURE OF 101,325 kPa.
4.3.1 Apparatus. — (See Fig. 3).
(a) Glass jars. — Four straight-sided, cylindrical, screw top glass jars, each of capacity approximately 475 ml and with inside dimensions of height 100 mm and diameter 75 mm, with matching screw lids that will provide water and vapour-tight seals.
(b) Desiccators and covers.— Four bowl-form glass desiccators of inside diameter 250 mm, with matching tubulated covers fitted with No. 8 rubber stoppers.

(c) Desiccator plates. — Four perforated porcelain plates, without feet, glazed on one side, and of diameter 230 mm.

4.3.2 Reagents.
(a) Ammonium sulphate, reagent grade.
(b) Distilled water.
(c) Compatibility fluid corresponding in quality to the reference standard of the South African Bureau of Standards and with an equilibrium reflux boiling point of not less than 182 °C when tested in accordance with 4.1.
4.3.3 Procedure.
4.3.3.1 Lubricate the ground glass joints of the desiccators with silicone grease. Into each desiccator place 450± 25 g of the ammonium sulphate and add 125±10 ml of the distilled water. The surface of the resultant ammonium sulphate slurry shall lie within 45±7 mm of the top surface of each desiccator plate. Use a fresh charge of ammonium sulphate slurry for each test. Condition the charged desiccators with their covers on and stoppers in place at a temperature of 23±2 °C for at least 12 h before use.
4.3.3.2 Determine the water content of the compatibility fluid, using a method of determination that is sufficiently accurate to measure the mass of water added to samples of the compatibility fluid within approximately 15 per cent of the water added for additions up to 0,8 per cent (m/m), and within approximately 5 per cent of the water added for additions greater than 0,8 per cent (m/m).
4.3.3.3 Adjust the water content of the compatibility fluid to 0,50±0,5 per cent (m/m) and pour 100±1 ml of this fluid into cadi of two of the glass jars. Pour 100 ±1 ml of the test fluid into each of the remaining two glass jars. Immediately place the jars separately into the four charged and conditioned desiccators, replace the desiccator covers and maintain the temperature throughout the humidification procedure at 23±2 °C. At intervals, remove the rubber stopper in the top of each desiccator that contains the compatibility fluid. Use a long needled hypodermic syringe to withdraw a sample of not more than 2 ml from each jar and determine its water content in accordance with 4.3.3.2. Do not remove more than 10 ml in total of the compatibility fluid from each jar during the humidification procedure. When the average water content of the duplicates of the compatibility fluid roaches 3,50 ± 0.05 per cent (m/m), remove the two fluid test specimens from their desiccators and immediately cap each jar tightly. Determine the equilibrium reflux boiling points of the duplicate test specimens in accordance with 4.1. If the two results agree within 4 °C, record the average as the wet equilibrium reflux boiling point. If the two results differ by more than 4 °C, repeat the test and record the average of the four individual equilibrium reflux boiling points as the wet equilibrium reflux boiling point.

4.4 KINEMATIC VISCOSITY.

4.4.1 Apparatus. — A calibrated capillary type viscosity tube capable of measuring viscosity to within the limits of error given in Table 3.
4.4.2 Procedure. — Determine the kinematic viscosity of the fluid at —40 °C and at 100 °C taking particular care to avoid contamination of die fluid by condensation of atmospheric moisture during the determination at — 40 °C.

4.5 NEUTRALITY.
4.5.1 Apparatus. — A pH meter equipped with a calibrated glass electrode and a calomel reference electrode.
4.5.2 Procedure— Mix equal volumes of the fluid and an 80 per cent aqueous (distilled water) solution of ethanol having a pH value of 7,0±0,1. Distilled water with a pH value of 7,0d=0,l may be used instead of the alcohol solution if the fluid is miscible with an equal volume of water. Determine the pH value of the mixture at a temperature of 23± 5°C.

4.6 CORROSIVENESS.

4.6.1 Metal strips. — Prepare as follows from the metals listed in Table 1 three sets of corrosion test strips corresponding in composition and dimensions to the reference standard of the South African Bureau of Standards: With the exception of the tinned iron strips, clean the strips by abrading all surfaces with 320A waterproof
silicone carbide paper wetted with 95 per cent ethanol until all surface scratches, cuts, and pits have been removed from the strips. Use a new piece of silicone carbide paper for each different type of metal. With the exception of the tinned iron strips, polish the strips with No. 00 grade steel wool. Wash the strips, including the
tinned iron ones, with 95 per cent ethanol, dry them with a clean lint-free cloth, and place them for at least 1 h in a disiccator maintained at 23±5 °C. After polishing, handle the strips with clean forceps or tongs to avoid contamination. Determine the mass of each strip to the nearest 0,1 mg and assemble each set of strips on an uncoated steel cotter pin or bolt in the following order: tinned iron, steel, aluminium, cast iron, brass, and copper. Ensure that the strips are in electrical contact, and except for the cast iron strips bend them so that there is a gap
of 3,0±0,5 mm between adjacent strips for a distance of about 5 cm from the free ends of the strips. Measure the total exposed surface area of each strip. Immerse the strip assemblies in 95 per cent ethanol and then handle them only with clean forceps or tongs. Dry the assemblies with dried filtered compressed air and desiccate them at least 1 h before use.
4.6.2 Styrene-butadiene rubber cups.
(a) Take three styrene-butadiene wheel cylinder rubber cups corresponding in quality to the reference standard of the South African Bureau of Standards. Measure to the nearest 0,02 mm the base diameter of these cups along the centre line of the lettering on the cup and at right angles to this centre line. Take the measurements at least 0,4 mm above the bottom edge and parallel to the base of the cup. Do not use any cup for which the two measurements differ by more than 0,08 mm. Average the two readings of each cup.
(b) By means of a Micro-tester apparatus determine on the inner surface of the test cups the hardness of the cups in International Rubber Hardness Degrees.
4.6.3 Procedure. — Place one rubber cup, with the lip edge facing up, in each of three straight-sided round glass jars of capacity approximately 475 ml and inner dimensions of approximately 100 mm in height and 75 mm in diameter. Insert one metal strip assembly inside each cup with the pinned end in contact with the concavity of
the cup and the free end extending upward in the jar. Mix 760 ml of fluid with 40 ml of distilled water. Use this mixture to cover the metal strip assembly in each jar to a depth of approximately 10 mm above the tops of the strips. To close the jar use only tinned steel lids vented with a hole of 0,8±0,1 mm in diameter. Tighten the lids
and place the jars in an oven maintained at 100+2 °C for 120±2 hs. Allow the jars to cool at 23±5 °C for 60 to 90 min and then use forceps or tongs to take the strip assemblies out of the jars, removing loose adhering sediment by agitating each assembly in the fluid in its jar. Examine the strips and jars for adhearing crystalline deposits, disassemble the metal strips, remove adhearing fluid by flushing with water, and clean individual strips by wiping with a cloth wetted with 95 per cent ethanol. Examine the strips for evidence of etching and pitting. Place the strips in a desiccator maintained at 23±5 °C for at least an hour. Determine the mass of each strip to the nearest 0,1 mg. Determine the difference in mass of each metal strip and divide the difference by the total exposed surface area of the metal strip expressed in square centimetres. Average the results for the three strips of each type of metal. Immediately following (he cooling period use forceps or tongs to remove the rubber cups from the jars, removing loosely adhering sediment by agitation of the cup in the fluid in the jar. Rinse the cups in 95 per cent ethanol, air-dry them, and examine them for evidence of sloughing, blistering, and other forms of disintegration.
Determine the hardness and base diameters in accordance with 4.6.2 within 15 min after removal from the fluid. Examine the fluid-water mixture for jelling. Agitate the liquid in the jars to uniformly suspend any sediment, transfer a 100 ml portion of the liquid from each jar to a cone-shaped centrifuge tube [see 4.6.4.1 (b)] and
then determine percentages of sediment as described in 4.6.4. Measure as described in 4.5 the pH value of the fluid water mixture.

4.6.4 Determination of sediment.
4.6.4.1 Apparatus.
(a) 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 of 600-700 at the tip of the tubes. Calculate the required speed of the rotating head by means of the following equation:
rpm = 423 squareroot(rcf/d)
where rcf = relative centrifugal force
d — diameter of swing, in centimetres, measured between lips of opposite tubes when in rotating position
(b) Centrifuge tubes. — Centrifuge tubes made of thoroughly annealed glass and having the dimensions given in Fig. 4 and distinct graduations.

4.6.4.2 Procedure.- Balance the two centrifuge tubes or pairs of tubes containing the liquid under lest with their respective trunion cups and place them on opposite sides of the centrifuge head. Then whirl them for 10 min at a rate sufficient to produce a relative centrifugal force of 600-700 at the tips of the whirling lubes. Repeat this
operation until the volume of sediment in each tube containing brake fluid remains constant for three consecutive readings.
4.6.4.3 Recording. Record the average volume of sediment at the bottom of the centrifuge lubes to an accuracy of at least 0,1 ml.

4.7 FLUIDITY AND APPEARANCE AT LOW TEMPERATURES.
4.7.1 At —40 °C- Place 100±2 ml of fluid in a 125 ml sample bottle of outside diameter 37d_0,05 mm and overall length 165±.2,5 mm. Stopper the bottle with a cork and place for 144±4 h in a bath maintained at — 40±2 °C.
Remove the bottle from the bath, quickly wipe the bottle with a clean lint-free cloth saturated with acetone or 95 per cent ethanol, determine the transparency of the fluid by placing the bottle against a hiding power chart corresponding in design to the reference standard of the South African Bureau of Standards and by observing the clarity of the contrast lines on the chart when viewed through every part of the fluid. Examine the fluid for stratification and sedimentation. Invert the bottle and determine the time in seconds required for the air bubble to travel to the lop of the fluid.
4.7.2 At — 50 °C. — Use the same procedure as described in 4.7.1 but keep the bottle for 6±0,2 h in a bath maintained at — 50±2 °C.
4.8 EVAPORATION.
4.8.1 Procedure.— Determine to the nearest 0,01 g the mass of each of four covered Petri dishes, approximately 100 mm in diameter and 15 mm high. Place 25±1 ml of
fluid in each of the four tared dishes, replace the covers, and redetermine the mass to the nearest 0,01 g. Determine the mass of fluid from the difference in masses of the filled and empty dishes. Remove the covers, invert them, place each dish inside its cover in a top-vented, gravity-convection oven at 100±2°C; maintain this
temperature for 46±2 hs. Remove the dishes from the oven, replace the covers, cool in a desiccator lo 23±5 °C for 1 h, and determine the mass of each dish. Return all the dishes to the oven for a further 24d;2 hs, cool and determine the mass as before.
If at the end of 72±4 hs the average loss by evaporation is less than 60 per cent (m/m), terminate the test. Otherwise, continue this procedure until equilibrium is reached as evidenced by mass loss of less than 0,25 g in 24 hs on each dish, or until seven days have elapsed, whichever occurs first.
4.8.2 Calculation. — Calculate the percentage of fluid evaporated from each dish, average the results, and record this figure as the loss by evaporation.
4.8.3 Quality of residue. — Examine the residue in the dishes at the end of 1 h at 23±5 °C for compliance with 3.9.2 by rubbing any sediment with a fingertip to establish the presence or absence of grittiness and abrasiveness.

4.8.4 Pour point of residue. — Combine the residue from all four dishes in a 125 ml sample bottle (as described in 4.7.1) and store vertically in a cold bath at — 5±1 °C for 60±10 min. Quickly remove the bottle and place it in a horizontal position. The residue must flow not less than 5 mm along the bottle within 5 s.
4.9 WATER TOLERANCE.
4.9.1 At — 40. °C— Mix 3,5±0,1 ml of distilled water with 100±1 ml of fluid and pour the mixture into a cone- shaped centrifuge tube (see Fig. 4) as described in 4.6.4.1
(b). Stopper the tube with a cork and place it for 24±2 h in a cold bath maintained at — 40±2 °C. Remove the centrifuge tube from the bath, and quickly wipe the tube with a clean lint-free cloth saturated with acetone or 95 per cent ethanol. Place the tube against a hiding power chart corresponding in design to the reference standard
of the South African Bureau of Standards, and observe the clarity of the contrast lines on the chart when viewed through the fluid as a whole. Examine the fluid for stratification and sedementation. Invert the tube and determine the time in seconds required for the air bubble to travel to the top of the fluid. The air bubble shall be considered to have reached the top of the fluid when the top of the bubble reaches the 2 ml graduation mark of the centrifuge tube.
4.9.2 At 60 °C— Place, for 24±2 h, the centrifuge tube and fluid used for the test given in 4.9.1 in an oven maintained at 60±2 °C. Remove the tube from the oven and immediately examine the contents for stratification. Then determine the percentage by. volume of sediment as described in 4.6.4.
4.10. COMPATIBILITY.
4.10.1 At -40 °C— Mix 50±0,5 ml of fluid with 50±0,5 ml of compatibility fluid corresponding in quality to the reference standard of the South African Bureau of Standards. Pour this mixture into a cone-shaped centrifuge tube (see Fig. 4) as described in 4.6.4.1 (b), and stopper with a cork. Place the centrifuge tube for 24±2 h in a bath maintained at — 40±2 °C. Remove the centrifuge tube from the bath and quickly wipe the tube with a clean lint-free cloth saturated with acetone or 95 per cent ethanol. Place the tube against a hiding power chart corresponding in design to the reference standard of the South African Bureau of Standards, and observe the clarity of the contrast lines on the chart when viewed through the fluid as a whole. Examine the fluid for stratification and sedimentation.
4.11 RESISTANCE TO OXIDATION.
4.11.1 Preparation of metal strips. — Prepare and clear as described in 4.6.1 three sets of aluminium and cast iron corrosion test strips corresponding in composition and dimensions with the reference standard of the South African Bureau of Standards. Determine the mass of each strip to the nearest 0,1 mg and assemble a strip of each
metal on an uncoated steel cotter pin, separating the strip at each end with a piece of tinfoil approximately 12 mm in area and between 0,02 and 0,06 mm in thickness. The tinfoil shall contain at least 99,9 per cent of tin and not more than 0,025 per cent of lead.
4.11.2 Preparation of test mixture. — Place 30± 1 ml of fluid in a test tube of diameter 22 mm and length 175 mm. Add 60±2 mg of reagent grade benzoyl peroxide and 1,5±0,05 ml of distilled water to the tube. Stopper the tube and shake the contents without allowing the solution to wet the stopper. Place the stoppered tube in an oven
at 70±2 °C for 120±10 min, shaking every 15 min, to dissolve the peroxide. Remove the tube from the oven and allow to cool to 23±5 "C. Use this test mixture not later than 24 h after removal from the oven.
4.11.3 Procedure. — Cut a styrene-butadiene wheel cylinder rubber cup into eight sections of approximately equal mass and place one section in the bottom of each of three test tubes 22 mm in diameter and 175 mm in length. Add 10 ml of the prepared test mixture to each test tube. Place a metal strip assembly in each lube with the free
ends of the strips resting on the rubber, the test mixture covering about one-half the length of the strips, and the end having the cotter pin projecting above the fluid. Stopper the tubes with corks and store them upright for 70±2 h at 23=h5 °C. Loosen the stoppers, place the tubes for 168±2 h in an oven maintained at 70 ±2 °C and then
remove and disassemble the metal strips.

4.11.4 Examination and calculation. — Examine the strips for gum deposits. Wipe the strips with a cloth soaked in 95 per cent ethanol and examine for pitting, etching or roughening of their surfaces. Place the strips for at least 1 h in a desiccator maintained at 23±5 °C, then determine the mass of each strip to the nearest 0,1 mg, and determine the loss caused by oxidation by dividing the difference in mass of each metal strip by the total exposed surface area of each metal strip expressed in square centimetres. Record, to the nearest 0,05 mg per cm 2 . The average of the results for the three strips of each type of metal "separately.
4. 12 EFFECT ON RUBBER.
4.12.1 Rubber cups. — Four styrene-butadiene wheel cylinder rubber cups corresponding in quality to the reference standards of the South African Bureau of Standards. Measure the base diameter and hardness of each cup as described in 4.6.2 fa) and 4.6.2 (b) respectively. Do not use any cup for which the two base diameter measurements differ by more than 0,08 mm.
4.12.2 Procedure.
(a) At 70 °C. — Place two rubber cups in a straight- sided cylindrical glass jar having a capacity of about 250 ml and inside dimensions of approximately 125 mm in height and 50 mm in diameter. Add 75 ml of fluid to the jar. Close the jar tightly with a tinned steel lid. Heal the jar for 120±2 h at 70±2 °C. Allow the jar to cool at 23±5 °C for 60-90 min. Remove the cups from the jars, wash the cups immediately with 95 per cent ethanol, and air-dry them. Examine the cups for disintegration as evidenced by stickiness, blistering, or sloughing. Within 15 min after removal from the fluid measure the base diameter and hardness of each cup as described in 4.6.2 (a) and 4.6.2 (b) respectively.

(b) At 120 °C— Place the other two rubber cups in a 250 ml glass jar with lid [see (a) above]. Add 75 ml of fluid to the jar and heat for 70±2 h at 120:fc2 °C. Allow the jar to cool at 23±5 °C for 60-90 min. Remove the cups from the jars, immediately wash the cups with 95 per cent ethanol, and air-dry them. Examine the cups for
disintegration as evidenced by stickiness, blistering, or sloughing. Within 15 min after removal from the fluid measure the base diameter and hardness of each cup as described in 4.6.2 (a) and 4.6.2 (b) respectively.

4.13 SIMULATED SERVICE PERFORMANCE.
4.13.1 Test apparatus and materials.— A stroking test apparatus (see Fig. 5) corresponding in design and component quality to the reference standard of the South African Bureau of Standards and consisting of the following:
(a) Master cylinder assembly. — A new hydraulic brake system cylinder that has an inside diameter of approximately 28 mm, a cast iron housing and is filled with an uncoated steel stand pipe. The piston shall be of half hard copper base alloy.
(b) Brake assemblies. — Four new straight bore hydraulic brake wheel cylinder assemblies in cast iron housings that have diameters of approximately 28 mm and pistons made from unanodized aluminium alloy. Each assembly shall have a forward brake shoe with lining, a reverse brake shoe with lining, a front brake drum assembly, and the necessary assembly components.
(c) Braking pressure actuating mechanism. — An actuating mechanism for applying a force, free from side- thrust, to the master cylinder push rod. 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 6 900 kPa in the simulated brake system. A hydraulic gauge or pressure recorder that has a range of at least 0-6 900 kPa shall be installed in the system and shall be provided with a shut-off valve and with a bleeding valve for removing air from the connecting tubing. The actuating mechanism shall permit adjustable "stroking rates of approximately 1000 strokes per hour. A mechanical or electrical counter shall be used to record the total number of strokes.
(d) Heated air cabinet.— An insulated cabinet or oven that has sufficient capacity to house the four mounted wheel cylinder assemblies, master cylinder, and necessary connections and having a thermostatically controlled heating system to maintain a temperature of 120:±5 °C. Heaters shall be shielded to prevent direct radiation to
wheel and master cylinders.
4.13.2 Preparation of test apparatus.
(a) Wheel cylinder assemblies. — Disassemble the cylinders and discard the rubber cups. Clean all metal parts with 95 per cent ethanol and dry with clean compressed air. Inspect the working surfaces of all metal parts for scoring, galling, pitting, and cylinder bore roughness, and replace all defective parts. Remove any stains on cylinder walls with coarse abrasive cloth and 95 per cent ethanol. If stains cannot be removed, replace the cylinder. Measure the internal diameter of each cylinder at four positions approximately 19 mm from each end of the cylinder bore by taking the measurements in line with the hydraulic inlet opening and at right angles to this
centre line. Replace the cylinder if any of these four readings exceed maximum or minimum limits of 28,66 or 28,60 mm respectively. Measure the outside diameter of each piston at two positions approximately 90 degrees apart. Replace any piston if either reading exceeds maximum or minimum limits of 28,35 or 28,52 nun respectively. Select the parts to insure that the clearance between each piston and mating cylinder is within 0,08-0,13 mm. Use the new styrene-butadiene rubber cups corresponding in quality to the reference standards of the South African Bureau uf Standards. Ensure that all cups are free from lint and dirt and do not use any cup which has defects such as cuts, moulding flaws, or blisters. Measure to the nearest 0,02 mm the lip and base diameter of all test cups along the centre line of I he lettering on the cup and at right angles to this centre line. Determine the
base diameter measurements at least 0,4 mm above the bottom edge and parallel to the base of the cup. Do not use any cup of which the lip or base diameters differ by more than 0.08 mm. Average the lip and base diameters of each cup. Determine the hardness of all cups by the procedure specified in 4.6.2 (b). Clean the rubber parts with 95 per cent ethanol and lint-free cloth. Dry with compressed air. With the exception of housings and rubber boots dip the rubber and metal parts of the wheel cylinders in the fluid to be tested and install them in the cylinders. Operate the cylinders manually to ensure that they operate easily. Install the cylinders in the simulated brake system.

(b) Master cylinder assembly. — Disassemble the master cylinder and discard all rubber components. Clean and measure all metal components as described in 4.13.2 (a). Use new styrene-butadiene rubber cups corresponding in quality to the reference standard of the South African Bureau of Standards which have been inspected and cleaned as described in 4.13.2 (a) and measured as described in 4.6.2 (a). Prior to determining the lip and base diameters of the secondary cup, clip the cup in the test fluid, assemble on the piston, and maintain die assembly at 23±5 °C for at least 12 h in a vertical position. Inspect the relief and supply ports of the master cylinder and replace the cylinder if these ports have burrs or wire edges. Measure the internal diameter of the cylinder at two positions: approximately midway between the relief and supply ports and approximately 19 mm beyond the relief port towards the bottom or discharge end of the bore, taking measurements at each position on the vertical and horizontal centre lines of the bore. Replace the cylinder if any reading exceeds maximum or minimum limits of 28,65 or 28,57 mm respectively. Measure each of the outside diameters of the master cylinder piston at two points approximately 90 degrees apart. Replace the piston if any of these four readings exceed maximum or minimum limits of 28,55 or 28,52 mm respectively.

Except for the housing and push rod-boot assembly, dip the rubber and metal parts of the master cylinder in the fluid to be tested and install them in the cylinder. Operate die master cylinder manually to ensure that it operates easily. Install the master cylinder in the simulated brake system.

(c) Assembly and adjustment of test apparatus. — With the wheel cylinder assemblies and master cylinder installed, adjust the brake shoe toe clearance to 1,0 ±0,1 mm. Fill the system with the test fluid and bleed all wheel cylinders and the pressure gauge to remove entrapped air from the system. Operate the actuator manually to apply a pressure of more than the required operating pressure, and inspect the system for leaks. Adjust the actuator to obtain a pressure of 6 900 .±.300 kPa. Adjust to a smooth pressure-stroke pattern and a stroking rate of 1 000±100 strokes per hour. Record the fluid level in the master cylinder stand pipe. 4.13.3 Test procedure.- Operate the system for 16 000 ±1000 cycles at 23 ±5 °C. Repair any leaks, re-adjust the brake shoe clearances, and add fluid to the master cylinder stand pipe to bring to the level originally recorded. Restart the actuating mechanism and within 6±2 h raise the temperature of the cabinet to 120±5 °C. Ensure that the wheel cylinders are functioning properly and record at intervals of 24 000 strokes during test the amount of fluid required to replenish any loss. Stop the test at the end of 85 000 total recorded strokes, i.e. including the number of
strokes during operation at 23± 5 °C and the number of strokes during the period required to bring the system to the operating temperature of 120± 5 °C. Allow the equipment to cool to room temperature. Examine the wheel cylinders for leakage. Operate the assembly for an additional 100 strokes, examine the wheel cylinders for leakage, and record the volume of any fluid lost. Discard the results of any test in which mechanical failure occurs which may affect the evaluation of the test fluid, and repeat the test.
4.13.4 Dismantling of apparatus and inspection of operating parts. — Within 16 h after completion of the test, remove the master and wheel cylinders from the system and retain the fluid in the cylinders by immediately capping or plugging the parts. Disassemble the cylinders and collect the fluid in a glass jar. Clean the rubber cups
in 95 per cent ethanol and dry them with compressed air. Inspect the cups for stickiness, scuffing, blistering, cracking, chipping, and change in shape. Within an hour after disassembly measure the lip and base diameters of each cylinder cup as described in 4.13.2 (a) and 4.13.2 (b), with the exception that the lip or base diameters may differ by more than 0,08 mm. Determine the hardness of each cup by the procedure specified in 4.6.2 (b).

4.13.5 Recording and calculation of test results.— Record any sludge, or jelling, present in the fluid after the test. Within an hour after draining the cylinders, agitate the fluid in the glass jar to suspend and uniformly disperse any sediment present and transfer a 100 ml aliquot of this sample to a cone-shaped centrifuge tube [see 4.6.4.1 (b), and determine the percentage by volume of sediment as described in 4.6.4. Allow the tube and fluid to stand for 24 h, recentrifuge and record any additional sediment recovered.
Inspect the cylinder parts and record any gumming or any pitting en pistons and cylinder walls. Rub any deposits adhering to the cylinder walls with a cloth wetted with 95 per cent ethanol to determine its abrasiveness and removability. Clean the cylinder parts in 95 per cent ethanol and dry with compressed air. Measure and record the diameters of the pistons and cylinders as described in 4.13.2 (a) and 4.13.2 (b). Calculate the lip diameter interference set from the following formula:

Lip diameter interference set, % =(D1-D2)/(D1-D3) *100
Where D1 + original lip diameter
D2 = final lip diameter
D3 = original cylinder bore diameter. 

Reference of the measure

Regulation 4 

Measure also domestic

Yes 

Products affected by the measure.

Description

Hydraulic brake and clutch fluid 

Countries/Regions affected by the measure.

Description

All countries