520 / 1525
45
BRAKES
SERVICE CHECK
A. INSPECTION (As per recommended service
schedule)
Check the tightness of the mounting nuts
(torque 20 Nm)
B. OPERATING TESTS
l
Check for free movement of the push rod
without binding while applying/releasing
brakes.
l
Check for vacuum leak in brakes applied /
released position by observing the vacuum
gauge and ensure that the pipe lines and the
joints are free from leakage.
REMOVAL
1.
Place wheel chokes in front and behind the
wheels to prevent movement of the vehicle.
2.
Remove the brake pedal return spring
3.
Remove the fork pin of vacuum brake valve
4.
Disconnect the hydraulic lines
5.
Remove the master cylinder
6.
Disconnect vacuum line connected to Non
Return Valve.
7.
Loosen the mounting buts of vacuum brake
valve and remove the unit
DISASSEMBLY
1.
Clean the exterior of the unit.
2.
Loosen Nut (A/F 17) on Fork and remove Fork,
Gaiter, Retainer and Filters.
3.
Loosen Nuts (A/F 13) on Spacer & Remove
spacer and sealing ring.
4.
Remove the Non return valve and Grommet.
5.
Mark the position of the front & rear housing
to ensure proper orientation of master cylinder
mounting bolts in front housing with respect to
the rear housing-mounting bolts.
6.
Place and position the unit in the dismantling /
assembly fixture while fixture is clamped on a
bench vice.
7.
Place and position the swivel block on the front
housing.
8.
Tighten the fixture handle to rest on the swivel
block. Avoid over tightening.
9.
Rotate the rods and match the notches &
dimples in line. Do not over rotate otherwise the
assembly will get locked again. If loosening is
difficult, loosen the handle slightly and then rotate
the rods.
10. After the front housing gets unlocked loosen the
fixture handle slowly until the front housing gets
separated fully.
11. Remove the Spring, Push rod, Spring seat and
Rubber reaction disc.
12. Remove the Key retainer.
13. Press the Operating rod and remove Key.
14. Remove the operating rod assembly from the
valve body by pulling it out at the fork end.
15. Separate cover and rear housing assembly.
16. Lift the Diaphragm on rear housing from the
groove.
17. Remove theRetainer, Spacer and Seal fromRear
housing.
CLEANINGAND INSPECTION
1.
Wash and clean all metal parts and blow dry with
compressed air.
2.
Inspect all the parts for excessive wear and
deterioration.
3.
Check Valve body bore and outer diameter for
any score mark / crack / damage.
4.
Check for any excessive wear in rubber reaction
disc.
5.
Check for any damage in valve rubber cup in
operating rod assembly.
6.
Check for any damage or holes or cut marks on
Diaphragm.
REASSEMBLY
1.
Use recommended repair kit and diaphragm to
replace old parts
2.
Lubricate all moving parts (except diaphragm)
with Silicone grease. This grease is supplied
along with repair kit.
3.
Press in the Seal, Spacer and Retainer in the
rear housing using a soft mandrel and ensure
that the Seal seats properly on the rear housing.