Chevrolet 10 Series 1968, Service Manual

Page: 240 / 713

BRAKES 5-7
F ig . 10—Adjusting Type “ F ” Front Brakes
Brake Fluid
Use GM Hydraulic Brake Fluid No. 11 or equivalent
when servicing brakes. This brake fluid is satisfactory
for any climate and has all the qualities necessary for
proper operation, such as a high boiling point to prevent
vapor lock and the ability to remain fluid at low
temperatures.
In the event that improper fluid has entered the system,
it will be necessary to service the system as follows:
1. Drain the entire system.
2. Thoroughly flush the system with clean alcohol, 188
proof, or a hydraulic system cleaning fluid such as
“ Declene” .
3. Replace all rubber parts of the system, including
brake hoses.
4. Refill the system.
5. Bleed the system.
Pressure Bleeding—Dual System
1. Clean all dirt from top of main cylinder and remove
cylinder cover and rubber diaphragm.
2. Reduce fluid level in main cylinder until reservoirs
are approximately half full.
NOTE:
Make sure brake fluid in bleeder equip­
ment is at operating level and that the equipment
is capable of exerting 30 to 50 lbs. hydraulic
pressure on the brake system.
3. Install brake bleeder adapter J-22489 (fig. 13) on
main cylinder. Connect hose from bleeder equipment
to bleeder adapter and open release valve on bleeder
equipment.
4. Install brake bleeder hose on bleeder valve and
thread brake bleeder wrench, Tool J-7647 over
bleeder hose.
5. Pour a sufficient amount of brake fluid into a trans­
parent container to insure that end of bleeder hose
will remain submerged during bleeding. Place the
loose end of bleeder hose into the container. Be sure
the hose end is submerged in the fluid.
6. Open wheel cylinder bleeder valve by turning Tool
J-7647 (fig. 14) counter-clockwise approximately
3/4 of a turn and observe flow of fluid at end of
bleeder hose.
7. Close bleeder valve tightly as soon as bubbles stop
and brake fluid flows in a solid stream from the
bleeder tube.
8. Remove brake bleeder wrench and bleeder hose from
wheel cylinder bleeder valve.
9. Repeat Steps 4 through 8 on the remaining wheel
cylinders in the correct bleeding sequence.
10. Disconnect bleeder equipment from brake bleeder
adapter cover J-22489.
F ig . 11—A djusting Type “ F R -3 ” Rear Brakes
CHEVROLET TRUCK SERVICE MANUAL