Metering Valve; Combination Valve - Jeep J-10 Series 1982 Technical & Service Manual

(4) Position cylinder on support plate and install
cylinder mounting bolts. Tighten bolts to 18 foot-pounds
(24 N«m) torque.
(5) Insert brakeshoe connecting links through dust
boots and into pistons.
(6) Install Wheel Cylinder Clamp Tool J-8002 over
cylinder to retain internal components in cylinder.
(7) Tighten wheel cylinder brake line fitting.
COMBINATION VALVE
A three-function combination valve is used on all Jeep
models. The valve consists of a one-piece housing con
taining a front brake metering valve, a pressure differ
ential warning valve, and a rear brake proportioning
valve. The combination valve also serves as the junction
block for the front brakes.
Two different combination valves are used. Some
models may be equipped with the type-W valve (fig. 2G-
14), while other models may be equipped with the type-
D valve (fig. 2G-15). Although the two valve types differ
in external appearance and in internal component de
sign, valve function and operation is the same for both.
Combination valve location is the same for all models.
The valve is mounted on the inner side of the left frame
rail adjacent to the transmission (fig. 2G-16).
FRONT
OUTLET
PORT
METERING
VALVE
DUST COVER
FRONT
OUTLET
PORT
REAR
INLET
PORT
REAR
OUTLET
PORT
Fig. 2G-14 Type-W Combination Valve
70569
Combination Valva Operation
The front brake metering valve assists in providing
balanced front-to-rear braking. To accomplish this, the
metering valve holds off (delays) full hydraulic fluid
pressure to the front disc brakes until the rear drum
brakes overcome return spring tension and the linings
contact the drums.
When the brakes are not applied, the metering valve
permits the free flow of brake fluid. This feature allows
the fluid to expand and contract with changes in
temperature.
BRAKES 2G-25
1 DIFFERENTIAL I
METERING VALVE ' WARNING I PROPORT/ONER
I VALVE SWITCH I VALVE
FRONT
OUTLET
PORT
BOOT
METERING
VALVE
STEM
FRONT OUTLET
PORT j
REAR INLET
| PORT
REAR
OUTLET
PORT
PROPORTIONER
PISTON
41120
Fig. 2G-15 Type-D Combination Valve
When bleeding the front disc brakes, the metering
valve stem must be held out using Tool J-26869 on type-
W valves or Tool J-23709 on type-D valves. Refer to
Brake Bleeding for specific details regarding tool use.
The pressure differential warning valve activates the
brake warning lamp if a pressure loss in the front or
rear hydraulic system should ever occur. This feature is
provided as a method for alerting the driver if such a
system malfunction ever occurs.
The valve consists of a valve piston, and plunger-type
switch. If a pressure loss in either system occurs, a
pressure differential of 70 to 300 psi (483 to 2 068 kPa)
will cause the piston to shuttle toward the low pressure
side of the valve. As the piston moves, ramps on the
piston force the switch contact plunger upward closing
the switch contacts. This action completes the electrical
circuit between the switch and brake warning lamp
causing the light to illuminate. Unless the lock cylinder
is turned to the Off position, the warning light will
Fig. 2G-16 Combination Valve Location (Type-D Valve Shown)