ASTM D4290 for determining leakage tendencies of automotive wheel bearing grease
ASTM D4290 standard test method for determining the leakage tendencies of automotive wheel bearing grease under accelerated conditions
10. Procedure
10.1 Prior to each test, check the freedom of movement of the thrust loading shaft (Fig. 3) in the spindle. If binding is noted, remove and clean both shaft and spindle bore.
10.2 Install new cups in the cleaned hub in the location shown by Figs. 1 and 2.
10.3 Weigh an inboard and outboard bearing cone to the nearest 0.1 g. Using the grease packer shown in Figs. 5 and 6 and an extra set of cups, fill the cones with the test grease. Use care to avoid moving the rollers or bearing components while removing the cones from the cups and in all subsequent wiping and handling steps. Strike off excess grease flush with the front face of the cone (near small end of rollers) using a small spatula. Wipe all grease from cone bore, cone back face, exterior cage surfaces, and exposed roller surfaces with a clean, lint-free cloth or towel and reweigh. Adjust the grease weight in the inboard cone to 3.0 more or less 0.1 g and in the outboard cone to 2.0 more or less 0.1 g by wiping or adding grease to the groove between the cage and the cone back face. Apply a thin film of grease on the cups.
10.4 Distribute 55.0 more or less 0.2 g of grease in a uniform layer in the hub.
10.5 Weigh the leakage collector to the nearest 0.1 g.
10.6 Install the leakage collector, inboard cone, hub, and outboard cone on the spindle (Fig. 2). Lock the components in place with the end cap and screw. Install the spindle connector.
10.7 Referring to Fig. 3, adjust the thrust load as follows: Tighten the compression nut (G) until the spring (F) is seated against the back plate (E), but not compressed. Bring the lock nut (H) up to the compression nut (G). Without moving H, compress F by tightening G until the compression gage (J) will fit between H and G. Hold J in position and back off G until J is held firmly between H and G.
NOTE 4 - Compression gage J has been machined such that insertion and adjustment of G causes spring F to compress and apply a 111-N (25-lbf) axial load on the wheel bearings.
10.8 Insert the thermocouple in the spindle thrust rod and position the junction at the center of the outboard bearing position. Close the cabinet and position the motor to operating location.
NOTE 5 - Do not engage the drive at this point. Start the motor and adjust the speed to 1000 more or less 50 rpm. At this point observe and record the unloaded motor current (N).
10.9 Turn off the motor, engage the drive coupling, and lock in position. Set the timer to begin 20-h cycle. Restart the motor and again adjust the speed to 1000 more or less 50 rpm. Turn on the heaters and adjust the oven temperature to maintain the spindle temperature at 160 more or less 1.5°C (320 more or less 2.7°F). When the spindle temperature has stabilized at the test temperature, make no further adjustment of the oven temperature for the duration of the test.
10.10 A steady-state running torque will develop in the first 2 h of operation as indicated by a stabilized value on the meter. Record this value as steady-state current (T). Determine the motor cutoff value as follows:
C = 8(T - N) + N
where:
C = motor cut-off value, amps,
T = steady-state current, amps, and
N = unloaded motor current, amps.
Set the automatic torque cut-off of motor to value C.
10.11 Permit the apparatus to operate under the prescribed conditions of load, speed, and temperature for 20 6 0.25 h. If the preset torque cut-off is exceeded, the test will be terminated automatically.
NOTE 6 - The motor is protected by a 30-s time delay.
10.12 Open the cabinet and allow the tester to cool to approximately 55°C using ambient air and no additional cooling aids (that is, fans) to facilitate disassembly.
10.13 Weigh the leakage collector to the nearest 0.1 g and report the weight as grease leakage. The grease collector will contain about 15 g before overflowing. This represents about 25 % of the total grease charge. If the collector overflows, report grease leakage as +25 %.
11. Parts Cleanup
11.1 With a spatula, remove as much grease as possible from the hub, grease collector, end cap, and spindle connector.
11.2 Place the parts in a suitable clean container (preferably stainless steel) and cover with Penetone ECS. (Warning - See 8.1.) Install a loosely fitting cover and heat gently (70 more or less 10°C) until the parts are clean (several hours). Avoid prolonged (overnight) heating as parts corrosion can occur.
11.3 Remove the parts from the solvent and wash with hot running water. Rinse immediately with isopropyl alcohol. (Warning - See 8.3.) Air dry. If the parts will not be used immediately, apply a thin film of SAE 10W engine oil.
11.4 Use a spatula to scrape grease off of the spindle. Remove remaining deposits from the spindle using 00 grade steel wool Stoddard solvent. (Warning - See 8.4.) If strongly adherent deposits resist this treatment, remove the spindle and clean in hot Penetone ECS.
