Volkswagen Type II Transporter 1200 Series Shop Manual page 192

14-Brakes
10. HYDRAULIC SYSTEM
TO BLEED
Bleeding the hydraulic system is not a routine
maintenance operation and will only be necessary when
some portion of the hydraulic equipment has been
disconnected or fluid drained off, thereby allowing air to
enter the. system.
(1
~
Fill the fluid reservoir with clean hydraulic brake
fluid and maintain it at least half full throughout the entire
bleeding operation.
(2) Remove the bleeder valve dust cap on the right
hand rear brake, attach a rubber bleeder tube to the valve
and allow the other end of the tube to be immersed in a
small amount of fluid contained in a clean glass jar.
(3) Unscrew the bleeder valve one complete turn.
( 4) Depress the brake pedal slowly the full extent of its
travel and allow it to return without assistance.
(5) Repeat operation ( 4) until a constant stream of
clean fluid, without any air bubbles, is being discharged
into the glass jiu, hold. the brake pedal down and tighten
the bleeder valve.
(6) Carry out the bleeding operations on the other rear
wheel, the right hand front wheel and the remaining front
wheel in that order.
NOTE: Do not 'allow the fluid level in the reservoir to fall
below the half full level at any time during the bleeding
operation or air may enter the system Always use new
fluid for topping up the reservoir.
. (7) Finaliy, remove the bleeder tube, refit the dust
covers to the bleeder valves and top up the fluid in the
reservoir to within
*"
of the filler cap level.
Il. BRAKE FAULT DIAf.iNOSIS
(1) Brake pedal hard.
Possible cause
(a) Incorrect shoe linings fitted.
(b) 'Frozen pedal linkage.
(c) Restricted brake line from master cylinder.
(2) Brake drag due to pressure build-up.
(3)
(4)
Possible cause
(a) Incorrectly adjusted master cylinder push rod to
piston clearance. ·
(b) Clogged master cylinder compensating port.
(c) Frozen wheel cylinder piston/s.
(d) Frozen brake shoe linkage.
(e) Broken or stretched
br~e
shoe return springs.
(f) Frozen handbrake
cab~es.
(g) Blocked vent in fluid reservoir cap.
Low or spongy brake pedal.
. · ' Pos;ib/e cause
(a) Incorrectly adjusted
~rake
shoes.
(b) Lack of sufficient fluid in s-ystem.
(c) Air in brake hydraulic system.
Brake locks on application.
f.ossible cause
(a) Gummy linings due to oil or fluid contamination.
(b) Incorrect shoe adjustment.
Remedy
....:. Check and renew linings to recommended type.
- Rectify or renew pedal linkage.
- Check brake line and remove restriction or renew.
Remedy
- Check and adjust push rod stop plate to give
recommended pedal free travel.
- Check and remove foreign matter from port.
- Check and free up or renew wheel cylinder pistons.
Free up or renew brake shoes.
Renew defective springs.
Free up or renew.
Check vent and remove obstruction. ·
Remedy
- Check and adjust brake shoes.
- Check for leaks, replenish fluid to specified level and
bleed brake system.
· - Bleed hydraulic system.
Remedy
Clean and renew linings. '
- Check and adjust shoes.
192