Chevrolet 10 Series 1970 Service Manual page 315

1 2 3 4
1 Nut
2 Valve Body
3 Inlet and Exhaust
Valve
4 Valve Body O-Ring
5 Valve Lower Body
6 Spring
7 Piston O-Ring
8 Cover Screw
F i g . 1 2 8 — T r a i l e r E m e r g e n c y V a l v e
Removal
1. B lock o r hold veh icle by a means other than a ir
brakes. Drain brake system .
2. Rem ove mounting nut (under dash). Rem ove a ll a ir
lin es to v a lv e .
Disassem bly
1. R em ove two screw s which hold va lve body, low er
body and lo w er body c o v e r together. Separate the
th ree p ieces.
2. R em ove piston spring and piston from lo w er body.
Rem ove " O " ring from
fro m lo w e r body.
3. R em ove " O " ring fro m va lve body.
4. R em ove plunger assem bly from valve body.
5. R em ove plunger nut, washer and inlet and exhaust
va lve fro m plunger. R em ove
6. R em ove va lve spring from va lve body.
Assem bly
1. Install va lve spring to va lve body.
2. Install " O " ring, exhaust va lve, washer and plunger
nut to plunger.
3. A ssem b le va lve body to plunger assem bly.
4. Install " O " ring to va lve body.
5. Install " O" rin g to lo w e r body, " 0 " ring to piston,
piston and piston spring to lo w e r body.
6. A ssem b le three p ieces, lo w e r body c o v e r, low er
body and va lve body and two screw s together.
Installation
1. Connect all a ir lin es to valve. Install mounting nut
under dash to T r a ile r E m ergen cy V a lve.
TRACTOR PROTECTION VALVE (Fig. 1 29)
The tra c to r protection va lv e autom atically c lo ses the
s e r v ic e and em ergen cy lines between the tra cto r and
5 6 7 8
9 Lower Body Cover
10 Lower Body O-Rin^
11 Piston
12 Plunger Nut
13 Plunger Washer
14 Valve Spring
15 Plunger O-Ring
16 Plunger
piston. Rem ove " O" ring
" O"
ring from plunger.
E M E R G E N C Y
C O N T R O L
V E N T
F i g . 1 2 9 — T r a c t o r P r o t e c t io n
1. C a p
2 . V a l v e S to p
3 . V a l v e
4 . P is to n
5 . C a p N u t
6 . G r o m m e t 1 - 1 / 1 6 " O . D .
tr a ile r i f the tra cto r a ir p ressu re drops to approxim ately
25 psi o r i f the tra cto r is disconnected from the tra ile r .
Used in conjunction with a t r a ile r em ergen cy control
v a lve, the tra cto r protection valve can operate autom ati­
ca lly o r be operated by a d r iv e r to make an em ergen cy
t r a ile r brake application.
Removal
1. Block o r hold veh icle by a means other than a ir
brakes. Drain brake system .
2. R em ove mounting nut (under dash).
3. R em ove mounting screw s. Rem ove a ll a ir lin es from
valve.
Disassembly
1. Rem ove retaining rin g from va lve body.
2. R em ove a ll va lve parts from inside o f body.
3. R em ove screw , w asher, diaphragm and inlet va lve
preload spring.
4. Separate exhaust check valve seat, va lve spring and
valve plunger.
5. R em ove " O" ring from check va lve seat.
6. Rem ove two " O" rin gs from plunger.
7. R em ove valve reta in er
Assembly
1. Install valve retain er and valve in plunger.
2. Install two " O'* rin gs in plunger.
" O"
3. Install ring in va lve seat.
BRAKES 5-77
V a l v e
7 . B o d y
8 . G r o m m e t 7 / 8 " O . D .
9 . G r o m m e t 3 / 8 " O . D .
1 0 . V a l v e S p r in g
1 1 . G r o m m e t 1 3 / 1 6 " O . D .
and valve fro m plunger.
CHEVROLET TRUCK SERVICE MANUAL