Trouble Shooting; Replace - Jeep UNIVERSAL CJ-2A Service Manual

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BRAKES
ered under the heading, "Wheel Cylinders."
Whenever the brake lining is renewed in one front
or one rear wheel be sure to perform the same oper-
ation in the opposite front or rear wheel, using the
same brake lining as to color and part number,
otherwise unequal brake action will result.
P- 1"2. Hydraul ic Brake Master Cylinder
Should it be necessary to recondition the master
cylinder, the method of removal is obvious.
After the master cylinder has been removed it
should be dismantled and thoroughly washed in
alcohol. Never wash any part of the hydraulic
braking system with gasoline or kerosene.
After the parts have all been thoroughly cleaned
with alcohol, make a careful inspection, renewing
those parts w)1ich show signs of being deteriorated.
Inspect the cylinder bore and if found to be rough
it should be honed out or a new cylinder installed.
The clearance between the piston and the cylinder
bore should be .001" to .005" [.025 to .127 mm.).
Clean out the cylinder with alcohol and with a wire
passed through the ports that open from the supply
reservoir into the cylinder bore, make sure that
these passages are free and clear of any foreign
matter. It is our recommendation that a new piston,
primary cup, valve and valve seat be installed
when rebuilding the master cylinder.
I nstall the valve seat in the end of the cylinder
with the flat surface toward the valve.
Install the valve assembly. Install return spring and
primary cup. The flat side of the cup goes toward
the piston. Install piston, stop plate, and lock wire
(retainer spring). Insta ll fitting connection with
new gasket. Fill reservoir half full of brake fluid
(see Par. B -33) and operate t he piston with the
piston rod until fluid is ejected at fitting. Install
the master cylinder to the frame and fill to a level
72"
[1,3 em.] below the top of the fill hole. M ake
the necessary connections and adjust pedal clear-
ance to
72"
[1 ,3 em.) free play
Bleed the brake lines as instructed in Par. P -4.
R echeck the entire hydraulic brake system to make
sure there are no leaks.
P-1 3. Wheel Cylinder
Some vehicles are equipped with 1" [25 mm.) di·
ameter front wheel brake cylinders, others with
l Ys• )29 mm.) diameter cylinders. B oth front wheel
cylinders and both rear wheel cylinders must have
the same diameter or unequal braking will result.
Make sure a replacement brake cylinder has the
same part number as the original cylinder.
To remove a wheel cylinder jack up the vehicle
and remove the wheel, hub and drum. Disconnect
the brake line at the fitting on the brake
backin~
plate. Remove the brake shoe return spring which
allows the brake shoes at the toe, to fall clear of
the brake cylinder. Remove two screws holdini
wheel cylinder to the backing plate.
R emove the rubber dust covers on ends of cylin-
der and t hen the piston a nd piston cups and the
spring. See Fig. 28 1.
230
Wash the parts in clean alcohol. Examine the cylin-
der bore for roughness or scoring. Check fit of pis-
tons to cylinder bore by using a .002" [.051 mm.)
feeler gauge. When reassembling the cylinder, dip
springs, pistons and piston cups in brake fluid. In-
stall spring in center of the wheel cylinder. Install
piston cups with the cupped surface towards the
spring so t hat the flat surface will be against the
piston. I nstall pistons and dust covers. I nstall wheel
cylinder to the backing plate, connect brake line
and install bra ke shoe return spring. R eplace wheel,
hub and drum, then bleed the lines as instructed
under heading, "Bleeding Brakes". Adjust brake if
required.
P-14. Kee p Grease and Oil off Brakes
No brake can be expected to work well when grease
or oil is a llowed to leak into the drum from the axle.
Little braking friction can be obtained between
brakes and d r ums when the surface is covered with
oil and grease.
Care should be exercised to see that excessive
amounts of lubricants are not put into the front
hubs or the rear axle bearings or differential. Keep
the grease retainers in good condition.
Whenever wheels a re removed, it is advisable to
wash off the drums with a suitable solvent so that
all grease a nd dirt are removed. Should there be a
quantity of grease on the linings, this can also be
washed off with solvent, however, should the linings
be thoroughly saturated with grease, there is noth-
ing that can be done except to replace the lining.
P-1 5. TROUBLE SHOOTING
P-16. Squeaky Brakes
In most cases, squeaks are entirely eliminated by
correct adjustment of the brakes. Squeaks may be
caused however, by glazed linings, lining wore thin
to the point of exposed rivets or by vibration. A
drum will not vibrate when t he brake is securing
uniform contact over the entire lining surface, ex-
cept when due to improper conditions such as the
linings becoming glazed. Glazed surface of the
brake linings may be removed by a stiff wire brush.
Occasionally squeaks are caused by roughened sur-
face of the drum, which can usually be remedied
by rubbing down with emery cloth and by wiping
the brakings surface clean. In extreme cases it may
be necessary to reface the drum in a lathe. Should
this be done, do not remove a metal thickness
greater than .030" [.762 mm.) - .060" [1.52 mm.)
overall diameter.
P-17. Rattles in Brakes
See that t he tension of the springs in the brakes
and attached to the control system are sufficient to
return brakes and brake mechanism to their normal
position. R eturn springs are so placed that they
keep all slack out of the control system by tension
on all j oints.
Brakes will not rattle inside t he drum if the springs
holding the shoes are kept at the proper tension.