SERVICE REPAIR
E80XL3 E100XL3 E120XL3 E100XL3S [C098]
1800 SRM 338
Description and Operation
General
This section has a description and the repair procedures for the parts of the hydraulic brake system. These
parts include the brake booster, master cylinder, and brake shoe assemblies.
Description and Operation
The master cylinder is actuated by a brake booster on
S3.50-5.50XL (S70-120XL) (D004) and H3.50-5.00XL
(H70-110XL) (F005/G005) lift trucks.
The brake
booster is a hydraulic valve actuated by the brake
pedal. The brake booster uses the oil that flows from
the steering control unit to multiply the force of the
brake pedal. The system allows braking without
hydraulic pressure at the brake booster.
Lift
trucks of
the E3.50-5.50XL (E70-120XL,
E70-120XL3) (C098) and E3.50-5.50XL, E4.50XLS
(E70-120Z, E100ZS) (D098/E098) series have a dif-
ferent master cylinder that is not actuated by a
brake booster.
BRAKE BOOSTER AND MASTER
CYLINDER
These parts are for the S3.50-5.50XL (S70-120XL)
(D004) and H3.50-5.00XL (H70-110XL) (F005/G005)
models. See Figure 1. The operation of the parts is
described in Figure 2.
MASTER CYLINDER
This master cylinder is for the E3.50-5.50XL
(E70-120XL, E70-120XL3) (C098) and E3.50-5.50XL,
E4.50XLS (E70-120Z, E100ZS) (D098/E098) models.
See Figure 3. The master cylinder has a housing
and a piston assembly. The housing has two ports
between the bore for the piston and the reservoir
for the fluid. The compensator port in front of the
piston is open when the piston is fully retracted.
The compensator port lets fluid move to or from
the brake system when the temperature changes.
Another port keeps fluid in the cavity around the
piston. The piston moves in the housing when the
operator pushes the brake pedal. A small movement
of the piston closes the compensator port. Hydraulic
pressure actuates the wheel cylinders as the piston
pushes fluid through the check valve. A return
spring pushes the piston back to the stop plate when
the