Disassembly/Inspection/Assembly

DISASSEMBLY

Fig. 5 Removing Caliper Piston:

Fig. 6 Exploded View Of Disc Brake Caliper Assembly:

1. Drain brake fluid from caliper.
2. Position caliper with shop cloths, Fig. 5, and apply compressed air to fluid inlet port to ease piston from bore. Do not attempt to catch piston or to protect it when applying compressed air, since personal injury is possible.
3. Remove dust boot, then the piston seal from bore, Fig. 6. Use wooden or plastic tool to remove piston seal since metal tools may damage piston.
4. Remove bleeder screw


INSPECTION

Clean all parts in denatured alcohol, wipe dry using lint-free cloths. Using compressed air, blow out drilled passages and bores. Check dust boots for punctures or tears. If punctures or tears are evident, new boots should be installed upon reassembly.
Inspect piston bores in both housings for scoring or pitting. Bores that show light scratches or corrosion can usually be cleaned with crocus cloth. However, bores that have deep scratches or scoring may be honed, provided the diameter of the bore is not increased more than .002 inch. If the bore does not clean up within this specification, a new caliper housing should be installed (black stains on the bore walls are caused by piston seals and will do no harm).
When using a hone, be sure to install the hone baffle before honing bore. The baffle is used to protect the hone stones from damage. Use extreme care in cleaning the caliper after honing. Remove all dust and grit by flushing the caliper with denatured alcohol. Wipe dry with clean lint-free cloth and then clean a second time in the same manner.


ASSEMBLY

Fig. 7 Installing Caliper Piston Boot:

Fig. 8 Installing Piston In Caliper:

1. Coat square cut piston seal with clean brake fluid, then install seal into piston bore. Work seal into groove with clean fingers.
2. Install and torque bleeder screw to specifications.
3. Lubricate boot and installation tool No. J-24548 with clean brake fluid, then place dust seal on tool, allowing 1/4 inch of tool to extend past small lip of boot, Fig. 7.
4. Place dust seal and tool over piston bore, then work large lip of boot into seal groove, Fig. 8. Ensure dust seal is fully seated.
5. Lubricate caliper piston and insert through tool. Center piston in bore and use a hammer handle to apply pressure to install piston halfway into bore, Fig. 8.
6. Remove installation tool No. J-24548 and seat small lip of boot in caliper piston groove, then bottom piston in bore.