Ball-and-Ramp Caliper Service
The ball-and-ramp caliper assembly works by using
three steel balls along matching tapered ramps to apply the
brake pads. To replace the pads without disassembling the
caliper, a special tool, Figure 13-21, must be used to turn
the piston into the caliper bore. Carefully push the piston
back into the caliper using the special tool to bottom the
piston in the caliper bore. There is no way to bottom the
piston without using this tool.
Cam-Type Caliper Service
The cam-type caliper is a simple design in which an
eccentric cam moves a rod. The rod pushes the piston
and pads into contact with the rotor. The rod is threaded
and mates with an adjusting nut in the piston. The rod and
adjusting nut remove any slack caused by pad wear. To
retract the piston when new pads are installed, the piston
should be turned clockwise as shown in Figure 13-22.
Rear Caliper Reinstallation
Rear caliper reinstallation is the reverse of installation.
If it was removed, reinstall the rotor. Place the new pads in
the caliper or on the rotor assembly. Reinstall the caliper and
reconnect the parking brake linkage if it was removed. If the
vehicle uses an electrical wear sensor, attach the electrical
connector. If needed, bleed the system. If the vehicle has a
drum-in-disc system, be sure to adjust the parking brake. Be
sure to stake the pads if necessary.
Adjusting Rear Disc Brake Calipers
After rear disc brake service, you may need to adjust
the caliper pistons to the rotors. In some cases, the brake
pedal only needs to be pumped several times to bring the
pads in adjustment. However, a special adjustment proce-
dure is sometimes needed to bring the pads into position
and to obtain a good pedal.
Using a flat-head screwdriver, carefully position the
tip against the top lip of the caliper piston, Figure 13-23.
Clamp a pair of vice grips on the caliper’s parking brake
Chapter 13 Disc Brake Service 217
Figure 13-17. A—A rear wheel disc brake assembly, with the
r parking brake cable and hook disconnected from the caliper
apply lever. B—A screw-type rear disc caliper assembly.
Remove the parking brake cable and lever to push in the piston.
Figure 13-18. A spanner wrench is sometimes needed to turn
screw-type rear caliper pistons into the body. (Bendix)
e vi se S Sp anner
"D D" shaped