DANA 53R-300, Service Manual

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Chapter 5
25150 Posi-Stop Brakes
Disassembly and reassembly of the Series II liquid cooled, spring applied hydraulic
released brake assembly.
Warning: Do not make any attempt any repairs he brake until this text is
completely read, understood and all safety precautions complied to.
1. Drain axle wheel end thoroughly.
2. Disassemble wheel end from spindle including the removal of the wheel hub
from the brake discs.
Note:
If spindle or axle housing is to be replaced,
remove brake as an assembly by removing the brake to spindle nuts and
washers. Remove brake assembly from the spindle.
NOTE: It is imperative a special disassembly and reassembly spring compression
tool be fabricated before disassembling any part of this brake. A drawing of this
tool is included in this text (Fig. A).
3. Install spring compression tool cylinder portion axle spindle, through brake
discs and against the piston pressure ring.
4. Install the round portion with the bolts over the spindle. Back the bolts out far
enough they do not contact the cylinder face.
5. Install spindle nut and tighten securely against compression tool.
6. Tighten the four (4) compression tool bolts against the compression tool
cylinder. This will hold the springs in position while removing the brake cover
and brake discs.
WARNING: Outer brake housing cover is under 72,000 lbs of
compressed spring pressure. EXTREME caution must be taken in
removing this cover. Brake cover bolts must be removed cautiously and
evenly.
DO NOT REMOVE BRAKE COVER BOLTS ONE (1) AT A TIME!!
7. With the spring compression tool securely in place, remove the brake cover
bolts evenly.
Do not remove bolts one at a time
.
8. Remove brake cover and piston from brake housing.
9. Remove friction and reaction discs.
10. Cautiously and evenly turn the compression tool bolts out one (1) thread at a
time. The compression springs will push the piston pressure ring out of the
brake housing.
WARNING: Before removing compression tool from spindle, make sure all
spring force is off pressure ring and ring moves freely in brake
housing.
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