Sunbeam ALPINE I SERIES: APLINE II SERIES, Workshop Manual

Page: 296 / 413

WSM.124
Section K (Brakes)
Test 3. It Indicates leaking gaskets, air valve or
rubber grommet. Clamp the vacuum hose
and repeat Test 3. If satisfactory, the non­
return valve is faulty. To test for a leaking
air valve run the engine and place the finger
over the air Inlet. If the suction is only slight
the air valve is satisfactory and the leak is
elsewhere.
Test 4. The source of the trouble can only be
found by elimination. Check for leaks. If
no leak of hydraulic fluid is evident clamp
each hose successively and repeat the test
each time. Finally plug the master cylinder
Page 37
outlet and test. If creeping of the pedal Is
evident when the hoses are clamped and
the pedal Is solid when the master cylin­
der outlet Is plugged, the servo un.lt Is
faulty.
Test 5. If the brakes remain on, disconnect the
vacuum pipe, operate the brakes to elimi­
nate all the vacuum in the servo unit and
repeat the test. If the brakes remain on,
the fault is not in the servo unit. If the
brakes now release normally, the fault is in
the servo unit and the alignment of the
piston In the vacuum cylinder is suspect.
FAULT FINDING CHART
FAULT
Hard pedal-Apparent lack of servo
assistance with engine running.
Brakes hanging on.
CAUSE
Lack of vacuum.
ii Restricted hose.
iii Rubber grommet.
iv Blocked air filter.
v Faulty output piston.
vi Major fault in servo unit.
Misaligned vacuum piston.
ii Swollen rubber grommet or
piston backing ring.
ACTION
i Check vacuum connections
ii Check hose and renew If
necessary.
iii Fit new parts from Service
kit.
iv Examine air filter element
and renew If necessary.
v Flt new parts from Service
Kit.
vi Fit new servo unit.
Check as Test No. 5.
ii Fit new parts from Service
Kit.