Chevrolet 70 1969 Series, Shop Manual

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POWER BRAKE 5-22
TRACTOR PROTECTION (BREA KA W A Y) V A LVES
CONVENTIONAL MODELS
OVERHAUL
BEN DIX-W ESTINGHO USE TRACTOR
PROTECTION VALVE
M IDLAND-ROSS TRACTOR
PROTECTION VALVE
DISASSEMBLY (Fig. 24) DISASSEMBLY (Fig. 25)
1. Remove retaining ring from valve body. 1. Remove snap ring from valve body.
2. Remove all valve parts from inside of body.
2. Remove plastic piston stop and O-ring from valve
3. Remove screw, washer, diaphragm and inlet valve body.
preload spring.
3. Rem ove piston assembly from valve body. Remove
4 Separate exhaust check valve seat, valve spring and block vee and O-ring from piston.
valve plunger.
4. Remove piston return spring.
5. Remove O-ring from check valve seat.
5. Remove screws and lock washers from front of pro­
6. Remove two O-rings from plunger. tection valve.
7. Remove valve retainer and valve from plunger. 6. Rem ove end cap assembly. Remove O -ring from end
cap.
ASSEMBLY
7. Remove irilet valve disc and inlet valve spring from
end cap.
1. Install valve and valve retainer on plunger. 8. Using a blunt punch, tap the exhaust valve L IG H T ­
2.
Install two O-rings on plunger. LY from the back of tractor protection valve. Plastic
3. Install O-ring on check valve seat. valve spool should fall out of body.
4. Assem ble exhaust check valve seat, valve spring and 9. Remove two O-rings from plastic valve spool.
valve plunger.
10 Remove exhaust valve spring from valve body.
5. Install inlet valve preload spring, diaphragm , washer
and screw.
1 1. Remove exhaust valve assembly from valve body.
6. Insert valve parts in valve body.
7. Fasten by installing retaining ring.
1
Valve Body
8
Screw
2
Plunger O-Ring
9
Retaining Ring
3
Valve Plunger 10
Check Valve O-Ring
4
Valve 11
Exhaust Check Valve
5
Inlet Valve Preload
Seat
Spring 12
Plunger O-Ring
6
Diaphragm 13
Valve Spring
7
Diaphragm Washer
14
Valve Retainer
T
-2794
1 Snap Ring
2 O-ring
Piston Stop
Block Vee
Exhaust
Valve Assy.
Spring
O-ring
8 Spool
9 O-ring
10 Lock Washer
11 Screw
12 Spring
13 End Cap
14 Valve
15 O-ring
16 O-ring
17 Piston
18 Spring
19 O-ring
20 Body
21 Ball
T-2796
Figure 24— Tractor Protection V alv e (B-W ) Figure 25 — Tractor Protection V alv e (M -R )
CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L