8-29
TMS800E SERVICE MANUAL UNDERCARRIAGE
Published 01-29-2014, Control # 496-00
Spring Brake Actuator
The upper part of the brake air chamber containing the large
spring is not serviceable; however, the lower part of the
assembly is serviceable.
1. Remove the caging bolt and washer from its storage
hole on the outside of the brake chamber.
2. Remove the dust cap from the bolt hole in the top of the
chamber.
3. Insert the head of the caging bolt through the opening
and turn bolt 1/4 turn clockwise.
4. Thread the nut and washer on the bolt and turn the nut
clockwise about 18 to 21 turns. Air pressure can be
applied to the spring brake chamber through the parking
port to compress the spring while the nut is being
tightened.
5. Do not force the nut beyond its normal stop. A torque of
40.6 Nm (30 lb-ft) is the maximum that should be
required. Reverse the procedure to uncage the spring.
Removal
1. Cage the spring brake.
2. Tag, remove, and cap the air lines to the brake air
chamber.
3. Remove the pin(s) connecting the clevis to the slack
adjuster.
4. Mark the position of the clevis on push rod so that the
clevis can be reinstalled in the same position.
5. Unbolt the air brake chamber from the mounting bracket
and remove the air brake chamber (see Figure 8-28).
Installation
1. Bolt the air brake chamber to the mounting bracket.
2. Install the pin through the clevis and slack adjuster.
3. Check brake adjustment.
4. Uncage the spring brake.
Disassembly
1. Remove the clamp securing the service brake chamber
to the spring brake chamber (see Figure 8-29).
2. Separate the lower cover from the spring brake
chamber.
3. If the push rod needs the spring to be removed, mark the
position of the clevis on the push rod. Remove the clevis
and jam nut.
4. Remove the push rod (see Figure 8-30).
Assembly
1. Insert the push rod through the spring and cover.
2. Screw on the jam nut and clevis as per removal marks.
WARNING
Spring brake unit is powerful enough to cause parts to fly
apart with enough force to cause personal injury. The
spring brake must be caged before removing or servicing
brakes before returning the crane to service.
Item Description
1 Brake Air Chamber
2 Axle No. 3
3 Torque Rod
4 Drive Shaft
5 Stabilizer Beam
6 Differential
7 Mounting Bracket
WARNING
Cage the spring brake before removal of air brake
chamber.
Reference Only