these cases, the outer pads must be pried to release them
from the caliper. Most pads will come off easily after the
caliper is removed from the rotor.
If necessary, check the pad thickness with a microm-
eter or caliper, and compare against service manual spec-
ifications. In most cases, however, the pads are obviously
worn enough to require replacement.
With the pads out of the way, carefully check the
caliper for damage or leaking. Also check the rotor as
explained later in this chapter. If the caliper shows any signs
of leakage or damage, it should be overhauled or replaced.
Many technicians prefer to install loaded calipers, which are
new calipers with the pads already installed.
Installing New Pads on the Front Calipers
Before installing the new pads, loosen the bleeder
screw and use a large C-clamp to push the caliper piston
into its bore. This is shown in Figure 13-12. Place the old
inner pad, a metal bar, or a block of wood on the piston
surface. This will minimize the chance of piston damage
from the C-clamp. Place a pan under the caliper to catch
brake fluid from the bleeder.
As soon as the piston is seated, stop turning the
C-clamp and tighten the bleeder screw. Continuing to turn
the C-clamp after the piston is seated may damage the
caliper. After the bleeder screw is tight, remove the
214 Auto Brakes
Figure 13-11. Always support the caliper with a wire hook.
Never let it hang by the brake hose. Hose damage may result.
Figure 13-12. Using a C-clamp and a metal bar to force the
caliper pistons back into their bores. This will provide the
necessary pad-to-rotor clearance when reinstalling the caliper.
Figure 13-10. A caliper assembly being removed. Note the
pads have come off with the caliper. (DaimlerChrysler)
Caution: While it is often possible to push
the calipers back into their bores without
loosening the bleeder screw, this may cause
damage to the master cylinder seals. It can also push
dirt and any debris into and through the hydraulic
actuator on ABS/TCS equipped vehicles. If this dirt
becomes trapped in the valves, it can cause the
hydraulic actuator to malfunction.
Note: The caliper components must
not be exposed to any petroleum based
lubricants. Use silicone compounds and
brake fluid for lubrication, and only where specified.