complete spring brake assembly.
If the vehicle is equipped with wedge brakes, special
instructions which apply to the actual removal of the air
chambers are covered in that particular brake section.
Prior to installing a new brake chamber assembly, be
sure that the pushrod and yoke are the correct length
and ports are correctly aligned with mounting bolts.
New brake assemblies are furnished with a 203.2 mm
(8") rod. Cut rod the same length as replaced unit
with spring brake fully released (release bolt completely
Assemble parking and service brake assembly
on vehicle mounting bracket. Torque nuts to
136-156 N.m (100-115 ft lbs). Be sure washers
are on outside of bracket and not against brake
Connect service brake pushrod yoke to slack
adjuster. Refer to the specific brake group
section if the vehicle is equipped with wedge
Connect air supply hoses to their respective
inlets on parking and service brake chambers.
Torque fittings to 34 N.m (25 ft lbs).
Adjust service brakes as outlined elsewhere in
Position parking brake control in released
position with at least 620 kPa (90 psi) air
pressure and apply service brakes. Inspect
both service and parking brake air connections
and both chamber assemblies for possible air
leakage at diaphragm with a soap solution.
Correct any air leaks which may exist.
With air still applied to the parking brake, turn
the release bolt clockwise until the bolt is fully
engaged into the unit and the slotted nut bottoms
out on the head insert. Tighten nut to 61-68
N.m (45-50 ft lbs). Do not use an impact wrench.
Install the breather cap by snapping it in place
over seal with arrow on breather pointing toward
Remove vehicle blocks.
REPLACE SPRING BRAKE DIAPHRAGMS
Remove complete brake chamber assembly as
a unit (refer to REEMOVE).
To avoid hazardous shop environmenttal
conditions, the warnings listed in this
disassembling the spring brake chamber
assembly. Sudden accidental release of the
components to be hurled with dangerous
force which could strike persons in the
area causing serious personal injury or
death. Under no circumstances should a
disassembled without first performing the
safeguards as described.
Prior to the disassembly of the spring brake
chamber assembly, check for broken parking
brake spring as follows:
Inspect the spring brake chamber clamp
band to be sure it is evenly seated around
the spring brake chamber.
Screw the release bolt clockwise all the way
into the unit, releasing the spring.
Shake the spring brake chamber assembly
vigorously. A rattling from within the head
end normally confirms a broken spring.
Further evidence of a broken spring would
be light resistance when screwing the
release bolt down.
If the parking brake spring is broken or
suspected of being broken proceed with
BRAKE WITH SUSPECTED DEFECTIVE
If the power spring is not broken, manually
release the power spring as instructed in
MANUAL SET OF SPRING BRAKE.
Using a hydraulic press, adjust it so that there
is 203 mm (8") of travel available for releasing
the spring after the ram has taken up some
pressure on the head of the unit.
CTS-4101W - Page 6