CD5515-2/YB5515-2 SERVICE MANUAL
9-8
Published 1-20-2017, Control# 483-02
1.
Shut off the engine and place chock blocks in front and
behind all four wheels. Release the parking brake.
Check that the brake moves freely on the guide/slide
pin.
2.
Loosen the lock nut and adjusting screw Figure 9-9.
3.
Place a 0.030 mm (0.012 in) feeler gauge between the
disc and one of the linings.
4.
Tighten the adjusting screw until it is just possible to
remove the feeler gauge.
5.
Tighten the jam nut while holding the adjusting screw
with a wrench. Remove the feeler gauge.
6.
Engage the parking brake. Then, release the parking
brake and recheck that the brake moves freely on the
guide/slide pin.
Accumulator Charging
The accumulator must be charged with NITROGEN. Do not
use compressed air. Remove the rubber cap over the
charging valve on top of the accumulator and install nitrogen
charging apparatus. Charge the accumulator to 51.71 ± 2.75
bar (750 ± 40 psi).
Residual Brake System Pressure
If residual pressure is greater than the pressure required to
overcome the brake retraction springs in the axle, brake
piston retraction will not occur resulting in excessive heat
and wear on the brake components,
If the residual pressure in the braking system is above 0.35
bar (5 psi) in the hot condition, the system should be
checked to identify the cause of the problem.
NOTE:
Pressure cannot build up in the hydraulic tank until
the oil is hot, or if the pressure is vented by
removing the tank cap/breather.
Checking For Residual Pressure
The following should be done with the engine running and
the hydraulic oil at working temperature.
1.
Apply and release the brakes. Check that the brakes
release immediately.
2.
If the brakes do not release immediately, place a
container under the axle hub to collect any spilled oil.
Unscrew the bleed nipple on the axle to release any
residual pressure.
NOTE:
The same effort should be needed to rotate the hub
with bleed nipple either open or closed. If the
problem affects only one hub, disassemble and
inspect the affected hub.
3.
If the brakes release immediately, residual pressure
should be suspected.
4.
If the brakes do not release immediately, tighten the
bleed nipple and check the following:
a.
Operation of the hydraulic tank breather.
b.
Foot brake valve operation.
c.
Hydraulic tank is overfilled.
TESTS
Brake Piston Seal Leakage Test (Front Axle
Only)
The following test procedure explains how to check if a brake
piston is severely damaged/destroyed or if the seals have a
small cut or nick. The test procedure must only be done
when the axle is COLD.
NOTE:
Before working on the brake system make sure the
crane is on level ground and chock all four wheels.
Do not drive the crane with any part of the brake
system disconnected. When the test has been
completed, reconnect all brake lines and bleed the
brake system using recommended procedures,
page 9-6.
1.
With the engine shut off and the parking brake engaged,
actuate the brake foot pedal until no resistance is felt
and the system pressure has been released.
NOTE:
Do not disconnect any lines until the brake circuit
pressure has been released.
2.
Remove and cap the brake piston feed line
A
Figure 9-10.
FIGURE 9-9
a0608
