Combination Valve - Jeep 1979 CJ-5 Technical & Service Manual

26-24 BRAKES
COMPRESSION
SPRING A N D
EXPANDERS
BLEEDER
SCREW
CJ M O D E L S
COMPRESSION
SPRING A N D
EXPANDERS
L I N K
DUST
BOOT
PISTON
PISTON CUP
80398
WHEEL
C Y L I N D E R
C H E R O K E E , W A G O N E E R
T R U C K M O D E L S
Fig. 2G-11 Wheel Cylinder
CAUTION: Do not clean brake parts with solvents con-
taining mineral oil such as gasoline, carbon tetrachlo-
ride, kerosene, alcohol, paint thinner or similar fluids.
Mineral oil causes swelling, deterioration, and pre-
mature aging of all rubber parts in the hydraulic sys-
tem. Use clean brake fluid or an approved brake
cleaning solvent only.
(4) Inspect wheel cylinder and pistons. Replace cyl-
inder if bore or pistons are scored, corroded, rusted,
pitted, worn, or cracked. If bore or pistons are only
discolored, or stained, polish bore or pistons lightly us-
ing crocus cloth only. Do not polish cylinder bore in
lengthwise direction, polish by rotating cylinder around
crocus cloth supported on fingers.
CAUTION: Do not hone the wheel cylinders at any
time or for any reason.
(5) Inspect bleeder screw and screw threads in cyl-
inder. Screw must turn freely. Replace screw if dam-
aged or replace cylinder if cylinder threads are
damaged.
(6) Inspect compression spring and integral expan-
ders. Replace spring if broken, distorted, lacks tension,
or if expanders are damaged in any way.
(7) Inspect rubber dust boots. Replace boots if cut,
torn, cracked, distorted.
(8) If cylinder bore or pistons were polished, clean
them using brake fluid or brake cleaning solvent and dry
using compressed air.
(9) Lubricate cylinder bore and all cylinder internal
components with new brake fluid. Do not lubricate dust
boots. Install them dry only.
(10) Position replacement piston cups on com-
pression expanders and install assembled parts in cylin-
der bore. Be sure expanders are seated in piston cups
and that cups are installed with lips facing one another
and toward interior of cylinder bore.
(11) Install pistons in cylinder bore. Be sure pistons
are installed with flat sides facing interior of bore.
(12) Install dust boots.
Installation
(1) Clean wheel cylinder mounting surface of sup-
port plate.
(2) Clean brake line fitting and threads.
(3) Start brake line fitting into cylinder. Do not
tighten fitting completely.
(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 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-
12), while other models may be equipped with the type-
D valve (fig. 2G-13). 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-14).