Brake Chambers
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Because no two vehicles operate under identical conditions, maintenance intervals will vary.
Experience is a valuable guide in determining the best maintenance interval for a vehicle.
WARNING! Spring Brake Chambers and Piggyback Spring Brake chambers contain a loaded
compression spring. Property damage, serious injury or death may occur if instructions are
not followed completely.
Every 300 operating hours, 8,000 miles, or
one (1) month:
1. Check push rod travel and adjust travel at the
slack adjuster if needed. Push rod travel should
be as short as possible without the brakes
dragging. Excessive push rod travel reduces
braking efficiency, shortens diaphragm life,
gives slow braking response and wastes air.
2. Check push rod to slack adjuster alignment
from release to full stroke position to be sure
the push rod moves out and returns properly
without binding at the non-pressure plate
hole or with other structures. Also check the
angle formed by the slack adjuster arm and
push rod. It should be greater than 90 degrees
when the chamber is in the released position
and approach 90 degrees at maximum
readjustment stroke.
3. Check tightness of mounting nuts. Torque on
the nonpressure plate mounting nuts should
be 110 lb-ft.
4. Check cotter pins to ensure they are in place.
5. Check all hoses and lines. They should be
secure and in good condition with sufficient
length to allow for axle movement.
Every 3,600 operating hours, 100,000 miles or
one (1) year:
1. Disassemble and clean all parts. Clean all metal
parts in cleaning solvent, removing all rust
and scale. Carefully inspect all metal parts for
cracks, distortion or damage. All diaphragm
sealing surfaces should be smooth and clean.
2. Install new diaphragm or any other parts if
they are worn or deteriorated. When the
diaphragm, spring, or both are replaced, they
should be replaced in the corresponding
chamber on the same axle.