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Trailer maintenance, Brakes, Brake adjustment – Multiquip DCA20SPXU2D User Manual

Page 38: Hydraulic surge brakes, Actuator

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PAGE 38 — DCA20SPXU2D 60 HZ GENERATOR • OPERATION AND PARTS MANUAL — REV. #1 (03/25/11)

TRAILER MAINTENANCE

BRAKES

Trailer brakes should be inspected the fi rst 200 miles of
operation. This will allow the brake shoes and drums to seat
properly. After the fi rst 200 mile interval, inspect the brakes
every 3,000 miles. If driving over rough terrain, inspect the
brakes more frequently.

Figure 38 displays the major hydraulic surge brake
components that will require inspection and maintenance.
Please inspect these components as required using steps
1 through 8 and Table 12 as listed below:

Brake Adjustment

1. Place the trailer on jack stands. Make sure the jack

stands are placed on secure level ground.

2. Check the wheel and drum for free rotation.

3. Remove the adjusting hole cover from the adjusting

slot at the bottom brake backing plate.

4. With a screwdriver or standard adjusting tool, rotate

the star wheel of the adjuster assembly to expand the
brake shoes.

5. Adjust the brake shoes outward until the pressure of

the lining against the wheel drum makes the wheel
diffi cult to turn.

6. Adjust, rotate the star wheel in the opposite direction

until the wheel rotates freely with slight lining drag.

7. Replace the adjusting hole cover and lower the trailer

to the ground.

8. Repeat steps 1 through 7 on the remaining brakes.

Hydraulic Surge Brakes

Hydraulic surge brakes (Figure 38) should not require any
special attention with the exception of routine maintenance
such as shoe and lining replacement. Brake lines should
be periodically checked for cracks, kinks, or blockage.

Figure 38. Hydraulic Brake Components

Actuator

Hydraulic surge braking requires the installation of an
actuator at the tongue of the trailer. Remember the surge
or push
of the trailer toward the tow vehicle automatically
synchronizes the trailer brakes with the tow vehicle brakes.
As the trailer pushes against the tow vehicle the actuator
telescopes together and applies force to the master cylinder,
supplying hydraulic pressure to the trailer brakes.

Periodically check and test the surge “actuator” to make sure that
it is functioning correctly. Never use an undersize actuator.

Table 12. Hydraulic Brake Troubleshooting

Symptom

Possible Cause

Solution

No Brakes

Brake line broken or kinked?

Repair or replace.

Weak Brakes or Brakes Pull to

One Side

Brake lining glazed?

Reburnish or replace.

Trailer overloaded?

Correct weight.

Brake drums scored or grooved?

Machine or replace.

Tire pressure correct?

Infl ate all tires equally.

Tires unmatched on the same axle?

Match tires.

Locking Brakes

Brake components loose, bent or

broken?

Replace components.

Brake drums out-of-round?

Replace.

Noisy Brakes

System lubricated?

Lubricate.

Brake components correct?

Replace and correct.

Dragging Brakes

Brake lining thickness incorrect or

not adjusted correctly?

Install new shoes and

linings.

Enough brake fl uid or correct fl uid?

Replace rubber parts

fi ll with dot 4 fl uid.