Brake Bleeding - Jeep J-10 Series 1982 Technical & Service Manual

2G-26 BRAKES
remain illuminated until the cause of the malfunction is
corrected and the valve recentered.
NOTE: The type D and W combination valves are hy
draulic self-reset types which do not require manual
recentering.
The rear brake proportioning valve provides balanced
front-to-rear braking action during high pedal pressure
stops. During light pedal pressure application, the pro-
portioner does not operate. Brake fluid normally flows
through the proportioner valve and into the rear brake
wheel cylinders. Spring pressure on the valve piston
holds it against the piston stop plate for normal brake
pressures.
Combination Valve Service
The combination valve is not repairable. If any section
of the valve is found defective, the entire valve assembly
must be replaced.
BRAKE BLEEDING
General
The brake hydraulic system must be purged of air
whenever a line has been disconnected or if air has
entered the system.
In most cases, it will be necessary to bleed only that
portion of the hydraulic system (front or rear) being
serviced. However, if a firm brake pedal cannot be ob
tained, or if diagnosis indicates the need, the entire
system must be bled.
Brake bleeding can be performed manually or with
pressure equipment. Bleeder screws are provided at the
calipers and wheel cylinders to simplify the bleeding
procedure.
Manual Bleeding Procedure
(1) Remove all accumulated dirt from master cylin
der and cover.
(2) Remove master cylinder cover.
(3) Fill master cylinder if required and install
cover.
(4) On vehicles equipped with type-W combination
valve, remove dust cover from metering valve stem and
install Tool J-26869 on stem to hold valve open (fig. 2G-
17).
(5) On vehicles equipped with type-D combination
valve, loosen valve front mounting bolt and insert
slotted end of Tool J-23709 under bolt. Push metering
valve stem inward (using tool) to hold valve open and
tighten mounting bolt to secure tool (fig. 2G-18).
(6) Bleed brake system in following sequence:
(a) right rear wheel
(b) left rear wheel
(c) right front wheel
TOOL
J-26869
70570
Fig. 2G-17 Metering Valve Tool Installation—
Type-W Combination Valve
(d) left front wheel
(e) master cylinder brake line connections
NOTE: Correct bleeding procedure is as follows: Place
wrench on bleeder screw. Install rubber hose on screw
with free end of hose submerged in a transparent con
tainer partially filled with clean brakefluid. Open bleed
er screw 3/4 turn. Have helper depress brake pedal.
Close bleeder screw before pedal reaches end of travel.
Have helper pump up pedal each time bleeder screw is
closed to ensure a good surge offluid when the screw is
reopened. Repeat bleeding process until fluid comes out
in a solid stream without the presence of air bubbles.
CAUTION: Do not allow the supply of fluid in the
master cylinder to become exhausted. Check the fluid
level frequently while bleeding and refill as required. Do
not bleed two wheels at a time and do 7iot bleed the
system with the front calipers or rear drums not in
place.
Fig. 2G-18 Metering Valve Tool Installation-
Type-D Combination Valve