DCA-70USI (50 Hz) —TRAILER MAINTENANCE
Brakes
Trailer brakes should be inspected the first 200 miles of operation. This will allow the brake shoes and drums to seat properly. After the first 200 mile interval, inspect the brakes every 3,000 miles. If driving over rough terrain, inspect the brakes more frequently.
Figure 57 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 13 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 difficult 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 57) 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 57. 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 13. Hydraulic Brake Troubleshooting
Symptom | Possible Cause | Solution | |
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No Brakes | Brake line broken or kinked? | Repair or replace. | |
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| Brake lining glazed? | Reburnish or replace. | |
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| Trailer overloaded? | Correct weight. | |
Weak Brakes or Brakes Pull to |
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Brake drums scored or grooved? | Machine or replace. | ||
One Side | |||
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| Tire pressure correct? | Inflate all tires equally. | |
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| Tires unmatched on the same axle? | Match tires. | |
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Locking Brakes | Brake components loose, bent or broken? | Replace components. | |
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Brake drums | Replace. | ||
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Noisy Brakes | System lubricated? | Lubricate. | |
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Brake components correct? | Replace and correct. | ||
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| Brake lining thickness incorrect or not | Install new shoes and | |
Dragging Brakes | adjusted correctly? | linings. | |
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Enough brake fluid or correct fluid? | Replace rubber parts | ||
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| fill with dot 4 fluid. | ||
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