8
Section 2
Hydraulic Brakes
DH Brake
(Duplex Hydraulic)
Description
The DH brake is a dual primary shoe, hydraulic
actuated brake and it is available in 16.50" x 4", 5"
and 6" (419.1 mm x 101.6 mm, 127 mm, 152.4
mm) sizes. The brake has manual adjustment.
Figures 2.8 and 2.9.
WARNING
Some brake linings contain asbestos fibers, a
cancer and lung disease hazard. Some brake linings
contain non-asbestos fibers, whose long-term
effects to health are unknown. You must use
caution when you handle both asbestos and non-
asbestos materials.
Figure 2.8
DH BRAKE
Disassemble DH Brake
WARNING
To prevent serious eye injury, always wear safe
eye protection when you perform vehicle
maintenance or service.
WARNING
Block the wheels to prevent the vehicle from
moving. Support the vehicle with safety stands.
Do not work under a vehicle supported only by
jacks. Jacks can slip and fall over. Serious personal
injury can result.
1. Make sure the vehicle is on a level surface.
2. Place blocks under the wheels not being
serviced to keep the vehicle from moving.
3. Raise the vehicle so that the wheels to be
serviced are off the ground. Support the
vehicle with safety stands.
4. Remove the wheels and brake drums from the
axle. If necessary, manually retract the brake
shoes by rotating the adjustment bolts so that
the brake drums will clear the linings.
5. Remove the cotter keys from the two shoe
guide bolts.
6. Install a wheel cylinder clamp to hold the
pistons in the wheel cylinder.
7. Push one shoe against the backing plate with
one hand and remove the shoe guide bolt nut
and washer with the other hand.
