Generic Race 50, Service Manual

Page: 33 / 209

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Trouble diagnosis program for hydraulic disc brake failure
Trouble diagnosis program for drum brake failure
Hydraulic disc brake
fails
Check brake fluid level in fluid
reservoir of brake master cylinder
Brake fluid level is below lower
limit line on fluid reservoir
Brake fluid level is above lower
limit line on fluid reservoir
Refill brake fluid
to upper limit line
on fluid reservoir;
also, check brake
caliper, brake
hose and hose
connector for oil
leak
If you have a sponge-like
feel when operating brake
grip
Residual air
exists in brake
line
Check if brake lining has been
worn to limit mark and if brake
disc is excessively worn
Replace brake
lining and brake
disc
1. Check surface of brake master cylinder piston and that of oil
cylinder wall for excessive wear or damage
2. Check brake master cylinder piston cup for damage, map
cracking and aging.
3. Check brake caliper gasket for damage, map cracking and aging.
4. Check surface of brake caliper piston and that of oil cylinder wall
for excessive wear or damage
Drum brake fails
Check if free stroke of brake grip is within
10mm~20mm or if that of brake pedal is within
20mm~30mm
Readjust Separate brake rocker arm from cable wire of brake control cable and then
pull brake rocker arm by hand to check
Brake rocker arm
rotates smartly but a
resistance is felt
when grasping
brake handle
Brake
rocker
arm
rotates
dully
Arrow on indicator board of
brake cam aligns with or
has exceeded “
▽
” mark on
brake hub cap
Arrow on indicator board of brake
cam does not align with “
▽
” mark
on brake hub cap
Cable wire
of brake
control cable
moves dully
in its jacket
when pulled
Movable
part on
brake cam
rusted or
locked by
foreign
material
1. Check arc surface on brake cam for
excessive wear
2. Check brake shoe plate for excessive
wear
3. Check bore of brake hub for
excessive wear
1. Check surface of brake shoe
plate for oil stains
2. Check if contact area percent
of brake shoe plate and brake
hub is less than 70%