Specifications; Power Brake Units - Jeep J-10 Series 1982 Technical & Service Manual

2G-28 BRAKES
(13) On vehicles equipped with type-W combination
valve, remove Tool J-26869 from metering valve stem
and install dust cover. On vehicles equipped with type-D
combination valve, loosen valve front mounting bolt,
remove tool J-23709, and retighten mounting bolt.
(14) Test brake operation before moving vehicle.
Brake Fluid
Brake Fluid Level
SPECIFICATIONS
General Specifications
Use Jeep brake fluid or
equivalent marked DOT 3
orSAE-J-1703only.
Fill master cylinder reservoirs
to within 1/4 inch
(6.35 mm) of reservoir rims.
80391
POWER BRAKE UNITS
General 2G-28
Power Unit Diagnosis 2G-30
Power Unit Installation 2G-30
GENERAL
Three power units are used on Jeep vehicles. An 8-inch
single diaphragm unit is used on CJ and Scrambler
models (fig. 2G-21). A 9-1/2 single diaphragm unites
used on Cherokee, Wagoneer and J-10 Truck models (fig.
2G-22) and a 9-1/2 tandem diaphragm unit is used on
J-20 Truck models.
Fig. 2G-21 Power Brake Unit and Bellcrank—
CJ and Scrambler Models
The power units consist of a two-piece outer shell
containing the single or dual diaphragms, air inlet valve,
air filter, control valve, power piston, reaction plate and
master cylinder push rod, and vacuum check valve (figs.
2G-23 and 2G-24).
Power Unit Removal
Power Unit Service
Specifications
Page
2G-30
2G-30
60645
Fig. 2G-22 Power Brake Unit—
Cherokee-Wagoneer-Truck Models
Power Unit Operation
The power unit utilizes a combination of engine vac
uum and atmospheric pressure to increase brake apply
force without increasing brake pedal efforts.
In the neutral (nonapplied) position, a vacuum is pre
sent within the chamber formed by the two halves of the
outer shell and on both sides of the power piston and
diaphragm.
As the brake pedal is pressed, the brake pedal push
rod moves the air inlet valve away from the control
valve (figs. 2G-23 and 2G-24). The control valve then
follows the air inlet valve until the control valve con-
~
~
~