Trailer Brake Hand Control V A Lves - Chevrolet 70 1969 Series Shop Manual

4. Install plunger in plunger seat.
5. Install guide post, inlet seat, spacer and lock nut on
plunger and seat assembly.
6. Install guide post, plunger, inlet seat and plunger seat

TRAILER BRAKE HAND CONTROL V A LVES

HAND CONTROL VALVE DISASSEMBLY—
TILT CAB MODELS
Key Numbers in Text Refer to Fig. 12
1. W ipe all dirt from exterior of unit. Remove air line
connector fittings from inlet valve cover and valve
cage.
2. U sin g a scribe or prick punch, m ark inlet valve cover
(1), valve cage (3), valve body, and valve cover (10) to
facilitate assembling parts in the same relative posi­
tions.
3. Rem ove four nuts (12) and lock washers (11) from
Inlet Delivery 26 25 24 23 22 21 20 19
Port Port
1 Inlet Valve Cover
2 Valve Cage O-rings
3 Valve Cage
4 Piston Spring
5 Piston Seal
6 Graduating Spring
7 Piston Cup Spacers
8 Piston Cup
9 Snap Ring
10 Valve Cover
11 Lock Washer
12 Nut
13 Valve Operating
Handle
14 Operating Handle
Shaft
15 Operating Cam
16 Self-locking Nut
Figure 12— Trailer Brake H and Control Valve-Tilt C ab
OVERHAUL
17 Bearing Plunger
18 Plunger Spacers
19 Friction Plunger
Screw
20 Friction Plunger
Spring
21 Friction Plunger
22 Snap Ring
23 Exhaust Filter
Screens and Felt
24 Valve Piston
25 Graduating Spring
Spacers
26 Piston O-ring
27 Exhaust Valve
28 Valve Spring
29 Inlet Valve
30 Valve Retaining Nut
TPM-7558
as an assembly, in body.
7. Install spring.
8. Install new gasket on upper cap. Install upper cap
studs. Remove cover (10) and handle (13) assembly
from studs.
4. Rem ove body from studs, then remove piston assem­
bly (24) and piston spring (4) from body. Remove
bearing plunger (17) and spacers (18) from piston cup.
D o not lose spacers (18). Rem ove O -ring (26) and
seal (5) from piston.
5. Rem ove cage (3) and valve assembly from studs. R e ­
move O -rings (2).
6. Rem ove nut (30), then remove inlet valve (29), ex­
haust valve (27), and valve spring (28) from cage.
7. Remove self-locking nut (16) from operating handle
shaft, then remove handle (13) and shaft (14) from
cover. Remove screw (19), friction plunger spring
(20), and friction plunger (21) from cover. Remove
operating cam (15) from cover, noting position of
cam in cover for reassembly.
8. Remove snap ring (22) and exhaust filter screens and
felt (23) from valve body.
9. D o not disassembly piston (24) unless necessary to re­
place parts as indicated later under " Cleaning, In ­
spection, and Repair."
CLEANING, INSPECTION, AND REPAIR
Repair Kit (Key Numbers Refer to Fig. 12)
A repair kit is available containing parts which should
always be replaced when overhauling the hand control
valve. Repair kit contains the following parts: Exhaust
valve (27), inlet valve (29), valve spring (28), O -rings (2
and 26), piston seal (5), piston spring (4), friction plunger
spring (20) and a valve cover gasket. Discard these parts
and install new parts at assembly.
Cleaning
W ash all parts in mineral spirits. M a k e sure compen­
sating passage in valve body and plunger bore in cover are
open and clean.
Inspection
1. Inspect internal bores in valve body and external sur­
faces of piston which have sliding contact with each
other for evidence of wear, scoring, or corrosion.
C heck exhaust valve seat at small end of piston and
inlet valve seat in valve cage for roughness. Slight im-
CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L
POWER BRAKE 5-15