Brake Caliper: Testing and Inspection

Cleaning and Inspection

NOTICE: Always use clean brake fluid to clean caliper parts. Never use mineral-base cleaning solvents such as gasoline, kerosene, carbon-tetrachloride, acetone, paint thinner or units of like nature as these solvents deteriorate rubber parts, causing them to become soft and swollen in an extremely short time.

1. Clean all metal parts using clean brake fluid. Remove all traces of dirt and grease. Do not use mineral base solvents to clean brake parts. After cleaning, wipe all fluid from boot counter bore in caliper and from boot groove in piston. These surfaces must be clean and dry at assembly to permit RTV to properly adhere.
2. Using an air hose, blow out all fluid passages in the caliper halves, making sure that there is no dirt or foreign material blocking any of these passages.
3. Discard all rubber parts. Boots, seals, and "O" rings should be replaced with new service kit parts.
4. Carefully inspect the piston bores in the caliper halves. They must be free of scores and pits. A scored or otherwise damaged bore will cause leaks and unsatisfactory brake operation. The bore surface should be restored by polishing with a very fine crocus cloth. If the bore surface cannot be restored using a very fine crocus cloth, it may be lightly honed. Replace the caliper half if either bore is damaged to the extent that light honing will not restore it.
5. Check the fit of the piston in the bore using a feeler gage. Clearance should be as follows:
1-7/8" Bore..........0.0045 to 0.010"
1-3/8" Bore..........0.0035 to 0.009"
If the bore is not damaged, and the clearance exceeds either of the upper limits, a new piston that does meet the clearance specified will be required.