Chrysler Full-Size Trucks 1997-2000 Repair Guide

Brake Shoes

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INSPECTION



  1. Brake shoes must be replaced as a set and preferably on both wheels at the same time.
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  3. Measure the thickness of both linings and compare to the minimum acceptable limit given in the specifications chart. Make your measurement at the thinnest point, if one is noted. Replace both shoes on both wheels if any one lining is below the limit. State safety inspection limits may differ from these limits and would naturally take precedence if greater (thicker) than the factory values.
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  5. Replace the linings if they are scored, contaminated with brake fluid or oil or otherwise damaged. Check drum as well. The perfect brake job would involve new linings and a resurfaced drum to ensure maximum braking effectiveness and maximum component service life.
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  7. Signs of fluid leakage must be investigated. Check the wheel bearing seals if oil is noted. Check the wheel cylinder if brake fluid is found on the brake plate or linings.
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  9. Examine the lining contact pattern to determine if the shoes are bent or the drum tapered. The lining should exhibit contact across its entire width. Shoes exhibiting contact only on one side should be replaced and the drum checked for runout or taper.
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REMOVAL & INSTALLATION



Due to the obvious safety concerns, brake work must not be undertaken casually.

For the newcomer, the safest approach to disassembling drum brakes is to work on one side at a time. Drum brakes have many small, indistinguishable parts and even assuming you get them back on the right side and the right way around there is the added complication of which part goes on first, second and next. Note that the many springs have unequal arms and must be fitted the right way. Steel stampings (plates, arms, etc.) are often fitted one on top of the other. Proper reassembly is extremely critical. Removing wheels and drums on both sides of the axle and using one side as a "go-by" for reassembly is a safe bet.

Specialized tools are available for drum brake jobs without which things can be very difficult. These include spring removal and installation tools, a brake gauge and adjusting tool.

  1. Block the front wheels. Raise the rear wheels and support the vehicle safely.
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  3. Be sure that the parking brake is fully released. Back off the parking brake adjuster, if necessary.
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  5. Remove the wheels.
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  7. Remove the brake drums.
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  9. Clean the brake assembly using either a vacuum, a water-dampened cloth, or brake cleaning fluid.
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CAUTION
Do NOT blow dust from the assembly with compressed air. Air-borne particulates may be a health hazard.

  1. With a spring tool, disconnect the return springs and adjuster lever spring.
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  3. With a suitable tool, compress the holddown springs and turn the retainers 90º. Release the spring and remove retainers and springs from the pins.
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  5. Remove the brake shoe assembly from the support plate.
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  7. Do NOT mix up parts from the two wheels. The brake adjusters are not interchangeable. The adjuster screw is stamped "L" or "R" for the wheel in which it is installed.
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  9. Installation is the reverse of removal.
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  11. Clean the support plate. Wire brush the lining contact areas on the plate and apply a thin coat of grease to prevent binding.
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  13. Check that the adjusters turn freely. Brush off corrosion and lubricate the mechanisms so that the threaded rod turns freely and without binding.
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  15. When installing the brakes, ensure that all components are properly seated. Do NOT force anything into place. Be sure the wheel cylinder links are seated on the brake shoes.
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Fig. Clean brake assemblies with specified brake cleaning fluid, a damp rag or vacuum: Do NOT use compressed air to blow assemblies clean



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Fig. Component locations of a typical drum brake



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Fig. Disconnecting a return spring with a special tool



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Fig. Depress the holddown spring and turn it 90º to release. This special tool makes it easier



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Fig. Removing the brake shoe assembly from the support plate



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Fig. Wire brush the lining contact areas (arrows) and lubricate them with grease



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Fig. Adjuster screw assembly: they are not interchangeable. Adjusters are marked "L" and "R" for the appropriate wheel



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Fig. The adjuster lever spring is installed first since one of the return springs is anchored on it



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Fig. Return springs must be hooked into the holes in the shoe (arrow). The spring long arm is attached to the pivot pin or the adjuster lever spring hook



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Fig. Installation of the adjuster lever spring and return spring

ADJUSTMENTS



Brakes are fitted with automatic adjusters. If they are functioning properly, brake adjustment should only be required if components are removed or replaced. Check that the adjuster star wheel moves freely, that the adjuster threads are clean and free of rust. A bit of high performance grease on the threads will keep adjusters in shape over the long haul.

Adjustment With Brake Gauge
  1. Ensure that the parking brake is fully released. There should be a bit of slack in the cable. Loosen the adjuster if necessary.
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  3. Raise the rear of the vehicle and remove the wheels and brake drums.
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  5. Check that both automatic adjuster cables and levers are properly connected.
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  7. Measure the drum diameter with the gauge and lock it into position.
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  9. Turn the gauge around and check the shoe diameter at the center of the shoes. The gauge should be a light drag fit over the shoes.
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  11. If the gauge is not a light drag fit over the shoes, lift the adjuster lever off the star wheel. Turn the star wheel by hand to move the shoes in or out so that the correct clearance can be achieved.
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  13. Install brake drums and wheels. Lower the vehicle.
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  15. Check brake operation before driving.
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  17. In a safe area, drive the vehicle forward a few yards and make one full stop. Then reverse and make one full stop. The vehicle must come to a complete stop each time. Rolling stops will not activate the adjusters.
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  19. Repeat this procedure 8-10 times to activate the automatic adjusters and equalize the brakes.
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  21. Adjust the parking brake.
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  23. Make a final check of brake operation before driving in traffic.
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Fig. Setting the brake gauge at the drum



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Fig. Checking shoes OD with the gauge: it should be a light drag after the gauge is set at the drum

Adjustment With Adjusting Tool

If the brake plate is equipped with adjuster slots, and if a brake adjusting tool is available, shoes can be adjusted without removing the drum.

  1. Ensure that the parking brake is fully released. There should be a bit of slack in the cable. Loosen the adjuster if necessary.
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  3. Raise the rear of the vehicle.
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  5. Remove the rubber plugs from the adjuster slots.
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  7. Check that the wheels rotate freely. If not, determine the cause. If the shoes are too tightly adjusted, skip the next step.
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  9. Insert the adjusting tool into the slot and engage the teeth of the adjusting star wheel. Move the tool handle up which will expand the brake shoes. Rotate the wheel while doing this until a slight drag can be felt.
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  11. Insert a thin slothead screwdriver into the adjuster slot and push the adjuster lever away from the star wheel. Back off the adjuster star wheel until brake drag is eliminated.
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  13. Install the adjuster slot plug.
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  15. Repeat the procedure at other wheel. Be sure adjustment is equal at both wheels.
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  17. Lower the vehicle.
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  19. Check brake operation before driving.
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  21. In a safe area, drive the vehicle forward a few yards and make one full stop. Then reverse and make one full stop. The vehicle must come to a complete stop each time. Rolling stops will not activate the adjusters.
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  23. Repeat this procedure 8-10 times to activate the automatic adjusters and equalize the brakes.
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  25. Adjust the parking brake.
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  27. Make a final check of brake operation before driving in traffic.
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Fig. The adjusting tool will expand the shoes, but to contract them, the lever must be pushed off the star wheel with a screwdriver

 
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