Chevrolet 10 Series 1968, Service Manual

Page: 318 / 713

BRAKES 5-75
A ssem bly
1. Position discharge valve return spring in body.
2. Install valve spring retainer in body.
3. Compress discharge valve return spring, install
valve disc and secure with nut.
4. Install new seal on end cap and install end cap in
body.
5. Install piston return spring in body.
6. Install new piston cup on piston and install piston in
valve body.
7. Install piston spring in valve body.
8. Install adjusting bearing in cam housing.
9. Install cam and camshaft in cam housing and place
assembly in position on valve body. Align scribe
marks made during disassembly. Secure by install­
ing collar.
10. Install operating lever and secure with nut.
11. Install cover and name plate and secure with pan
head screw.
Installation
1. If a new valve assembly is being installed, install
operating lever and shaft which were removed from
old unit. Also, install air line connector fittings in
inlet and outlet ports, using sealing compound on
connector threads. Keep sealing compound off first
two threads of fitting.
2. Position valve and secure with two bolts and lock
washers. Tighten bolts firm ly.
3. Connect air lines to valve.
40 Build up air pressure in system and test valve op­
eration as previously directed under "Serviceability
Tests".
DOUBLE CHECK VALVE (Fig. 113)
Disassem bly
Remove two cap screws and lock washers attaching
valve cover to body. Remove cover and gasket, then re ­
move shuttle valve and valve guide.
Installation
Wash all parts in a cleaning solution and wipe dry.
Examine all parts for corrosion or deterioration and re ­
place as necessary. Make sure shuttle valve will slide
freely back and forth in valve guide.
A ssem bly
Apply a thin coating of Lubriplate or equivalent to in­
side of valve guide. Place valve guide and shuttle valve
in body. Position cover on body, using new gasket. In­
stall cover cap screws and lock washers, and tighten
evenly and firm ly.
LIMITING QUICK RELEASE VALVE
OVERHAUL (Fig. 113) (TILT CAB MODELS)
Disassem bly
1. Remove cap screws and lock washers which secure
valve cover to valve body. Separate cover and body
and discard O-ring (5).
2. Push valve carrier with inlet and exhaust valve as­
sembly out of valve body. Remove O-rings from
grooves in valve body and discard.
Cleaning, Inspection, and Repair
Wash all metal parts in cleaning solvent. Examine
body and cover for cracks or other damage. Inspect ex­
haust valve seat in cover; if seat is nicked, chipped, or
worn, replace cover. Remove slight scratches or scores
from inner surface of body with crocus cloth. If any part
of the valve carrier and inlet and exhaust valve assembly
is scratched, nicked, chipped, or worn, the complete
assembly must be replaced.
Assem bly
1. Install new O-rings in grooves in valve body, then
place valve carrier assembly in body.
2. Place new O-ring on body, then install cover, making
sure valve guide enters bore in cover. Install cap
screws and lock washers and tighten firm ly.
3. After installing valve in vehicle, or using a test
hook-up, test valve as previously directed under
"Serviceability Tests."
F ig . 113-Front Lim iting V a lv e and Q u ic k Release V a lv e (T ilt Cabs)
EXH A U ST
V A LV E PISTON FROM A PPLICATIO N V A LV E
B O D Y
INLET V A LV E
INLET
PORT EXH AU ST V A LV E
FROM
TW O -W A Y
V A LV E
CHEVROLET TRUCK SERVICE MANUAL