Chevrolet 10 Series 1967, Руководство по обслуживанию, Страница: 246 / 605

BRAKES 5-30
3. Install bleeder valve in upper opening in each
cylinder.
4. Install brake shoes as directed under "Brake Shoe
Installation." Bleed brake system as previously
directed under “ Bleeding B rak es."
Type “ FR -3”
NOTE: Upper and lower wheel cylinders on
both right-and left-hand brakes are interchange­
able. Cylinders must be positioned on flange
plate so that the long stroke end of the cylinder
faces the shoe toe (adjustment end of shoe) or
the adjusting slot in backing plate. Make sure
mating surfaces of cylinders, heat shields, and
flange plate a r e clean to assure proper
alignment.
1. Position heat shield on each wheel cylinder, and in­
stall on flange plate. Attach each cylinder with two
cap screws and lock washers.
2. Attach connecting tube fitting to lower opening in the
upper cylinder, and to the upper opening in the lower
cylinder. Install bleeder screw in upper opening of
the upper cylinder. Connect brake line at lower
cylinder fitting.
3. Install brake shoes as directed under “ Brake Shoe
Installation." Bleed brake system as previously
directed under “ Bleeding B rak es."
BRAKE DRUMS
All front brake drums except those used on 3/4 and 1
ton trucks are the non-demountable type, that is, they
cannot be removed without removing the hub. Whenever
this type drum is removed, wheel bearings must be ad­
justed as outlined in Section 3. Rear brake drums on all
models are demountable, that is, they may be removed
without removing the wheel hub.
Removal
Front
1. Jack up front end of vehicle and remove wheel.
2. Remove hub and brake drum assembly.
NOTE: 3/4 and 1 ton drums may be removed by
removing
2
slotted head screws which retain
drums to hub. On all other models, hub and
drum are removed as an assembly.
3. Remove brake drum from hub as outlined in Section
3.
Rear
1. Jack up rear end of vehicle and remove wheel.
2. Remove countersunk screws, where used, and re­
move brake drum from outer flange of hub.
Inspection and Reconditioning
Whenever brake drums are removed they should be
thoroughly cleaned and inspected for cracks, scores, deep
grooves and out-of-round. Any of these conditions must
be corrected since they can impair the efficiency of brake
operation and also can cause premature failure of other
parts.
Smooth up any slight scores by polishing with fine
emery cloth. Heavy or extensive scoring will cause ex­
cessive brake lining wear and it will probably be neces­
sary to rebore in order to true up the braking surface.
An out-of-round drum makes accurate brake shoe
adjustment impossible and is likely to cause excessive
wear of other parts of brake mechanism due to its
eccentric action.
A drum that is more than .010" out-of-round on the
diameter is unfit for service and should be rebored. Out-
of-round, as well as taper and wear can be accurately
measured with an inside micrometer fitted with proper
extension rods.
If drum is to be rebored for use with standard size
brake facings which are worn very little, only enough
metal should be removed to obtain a true smooth braking
surface. If drum has to be rebored more than .010" over
the standard diameter, however, it should be rebored to
.060" oversize on the diameter and the brake facing
should be replaced with .030" oversize facings.
A brake drum must not be rebored more than .060
(.090" on 15" by 4, 5,
6
or 7" wide) over the maximum
standard diameter, since removal of more metal will
affect dissipation of heat and may cause distortion of
drum. Chevrolet brake facing is not furnished larger than
.030" oversize and this will not work efficiently in drums
bored more than .060" oversize.
Brake drums may be refinished either by turning or
grinding. Best brake performance is obtained by turning
drums with a very fine feed. To insure maximum lining
life, the refinished braking surface must be smooth and
free from chatter or tool marks, and run-out must not
exceed .005" total indicator reading.
Installation
1. Make sure mating surfaces of hub, drum and oil
deflector are clean and smooth and assemble as out­
lined in Section 3.
2. On front, install drum and hub assembly to wheel
spindle and adjust bearings on
1
/
2
,
1 1 / 2
and
2
ton
as outlined in Section 3. On 3/4 and 1 ton install
drum and retain in place with retaining screws.
3. On rear, assemble drum assembly over hub studs
and install retaining screws, if used.
4. Replace wheel assembly and lower vehicle to floor.
BRAKE PEDAL (EXCEPT TILT CAB AND
CHEVY VAN)
The brake pedal (fig. 56) is an integral design with the
clutch pedal, necessitating the removal of the clutch pedal
before removing the brake pedal.
Removal
1. Remove the clutch pedal as outlined under “ Clutch
Pedal" in Section 7.
2. Remove the pull back spring from the body bracket.
3. Remove the sleeve assembly screw attachment and
remove sleeve.
4. Disengage the push rod from the master cylinder and
drop the pedal to check for worn parts—inspect the
return spring, bracket attachment, and bushings for
needed repairs.
Installation
Reverse the above procedure and make certain the
brake pedal (fig. 56) is secure and adjusted properly be­
fore operating the vehicle. See Maintenance and Adjust­
ments for brake pedal adjustment.
BRAKE PEDAL-TILT CAB
The complete brake pedal consists of two separate
CHEVROLET TRUCK SERVICE M ANUAL