Fig. 23 Brake Chamber (Cross Sectional View)
11 Nut, Lock
12 Pin, Cotter
13 Pin, Clevis
14 Yoke, Clevis
particular spring brake chamber involved.
Disconnect air line and push rod yoke. Remove nuts
from mounting studs and remove chamber.
Position brake chamber on mounting bracket and install
nuts on mounting studs. Install lock nut and yoke on
push rod. Connect air line. Adjust yoke to slack
adjuster (see ADJUS ). Be sure end of push rod does
not bind with slack adjuster when brakes are applied.
To disassemble the brake chamber (numbers in
parenthesis) refer to Fig. 23.
Mark non-pressure plate (8), pressure plate
(4) and clamp (7). This will make it easier to
reassemble air chamber in its original position
and avoid installation interference.
Remove yoke (14) and lock nut (10) from push
Remove nuts and bolts from clamp ring.
Separate plates carefully since return spring
inside brake chamber is under tension.
With two sections of brake chamber separated
remove push rod, spring retainer (5) and spring
(6) from non-pressure plate.
Cleaning and Inspection
After brake chamber has been disassembled, proceed
Using a suitable cleaning solvent, clean all metal
Examine diaphragm. If any signs of damage
or deterioration are evident, replace diaphragm.
When one diaphragm requires replacement, it is
good practice to replace all brake chamber
diaphragms in the system while vehicle is out of
service. Brake chamber diaphragms must be
replaced once each year or every 160,000 km
(100,000 miles) regardless of condition.
Inspect push rod, spring and spring retainer. If
parts are damaged, they should be replaced.
Check return springs.If a load scale is available,
compare their tension with new spring. Matching
an old spring with a new spring will indicate
condition of old part.
clamping flanges on plates are dented or
damaged, replace plates.
Install nuts (10) on mounting studs and clamp
non-pressure plate (8) in vise with inside of plate
Install spring (6) in spring retainer (5).
Install push rod assembly in body, press
assembly down (brake applied position) to
compress spring and use vise grip pliers on
outside of push rod to hold spring compressed.
Install diaphragm (3) in pressure plate (4).
Position brake chamber plates matching up etch
marks made prior to disassembly.
Install clamp (7) with bolts and nuts and tighten
nuts to 17 N.m (150 in. lbs.) torque. Remove
vise grip pliers.
CTS-4080W - Page 16