Replace the fluid seals under any of the following
conditions: (a) fluid leakage around the pad; (b) brakes
overheat; (c) there is a large difference in left and right
pad wear; (d) the seal is stuck to the piston.
fluid seal is replaced, replace the dust seal as well.
Also, replace all seals every other time the pads are
Check the dust seals, dust covers, and 0 rings, and
replace any that are cracked, worn, swollen or otherwise
A. ·0" Ring
C. Fluid Seals
B. Dust Seals
Measure the cylinder inside diameter and piston out-
Replace the cylinder and piston if they are worn out
of tolerance, badly
Caliper Parts (Front and Rear)
Cylinder Inside Diameter
Piston Outside Diameter
For front calipers, caliper holder shafts must slide
smoothly in the caliper
If the shafts do not
slide smoothly, one pad will wear more than the
pad wear will increase, and constant drag on the disc
will raise brake and brake fluid temperature. Check to
see if the caliper holder shafts are badly worn or show
stepped wear, or the rubber friction boots are damaged.
If the shafts or friction boots are damaged, replace the
shafts, and caliper holder, and friction boots.
A. Caliper Holder
Caliper Holder Shafts
Brake line damage
C. Friction Boots
The high pressure inside the brake line can cause fluid
to leak or the hose to burst if the line is not properly
Bend and twist the rubber hose while examining it.
Replace it if any cracks or bulges are noticed.
Disc wear, warp
the disc may
disc will cause the brake pads to drag on the disc and
will wear down both the pads and disc
ing will also cause overheating and poor braking effi-
ciency. Poor braking can also be caused by oil on the
disc. Oil on the disc must be cleaned off with trichloro-
ethylene or a high flash-point solvent. Do not use one
which will leave an oily
Jack up the motorcycle so that the front wheel is
off the ground, and turn the handlebar fully to one
Set up a dial gauge against the front disc as
illustrated, and measure disc runout. Remove the jack,
set the motorcycle up on its center stand, and then
measure the rear disc runout.
If runout exceeds the
service limit, replace the disc.
A. Dial Gauge