Electronic Parking Brake Motor

This procedure addresses an anachronistic repair request: the 1992 Dodge Viper RT/10 was equipped with a conventional cable-operated mechanical parking brake and has no electronic parking brake motor. This guide explains the mechanical system and how to diagnose parking brake issues.

Warnings

Tools required

Parts

• Rear brake shoes (if worn) × 1 — Use OEM specification
• Parking brake cable (if seized or frayed) × 1 — Use OEM specification
• Brake hardware kit × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake firmly
2. Place wheel chocks in front of both front wheels
3. Loosen rear wheel lug nuts while vehicle is on ground (do not remove)
4. Raise rear of vehicle using floor jack at designated rear jacking point
5. Support vehicle securely on jack stands placed at rear frame rails
6. Remove rear wheels completely and set aside
7. Verify vehicle stability by gently pushing on rear bumper before working underneath

Procedure

1. 1

   Verify mechanical parking brake system
   Inspect the center console area and locate the mechanical parking brake lever between the seats. The 1992 Viper uses a conventional hand-operated lever with a release button, not an electronic switch or button. If you see an electronic switch or actuator, this is an aftermarket modification and this procedure does not apply. Trace the cable routing from the lever down through the transmission tunnel to confirm mechanical cable operation.
2. 2

   Inspect rear brake assemblies
   With wheels removed, examine the rear brake disc assemblies. Verify the actual rear parking brake design on this vehicle before proceeding. The 1992 Viper RT/10 rear parking brake actuates the rear disc caliper mechanically rather than using internal drum shoes; confirm whether your vehicle has a caliper-integrated mechanical parking brake or a drum-in-hat arrangement, as this determines the correct service procedure. Look for the backing plate access hole or rubber plug on the inboard side of the rotor hat. This is where parking brake adjustments are made.
3. 3

   Remove rear brake calipers for access
   To access the parking brake drum mechanism, the hydraulic disc brake calipers must be removed. Remove the caliper mounting bolts and carefully lift the caliper off the rotor. Support the caliper with wire or a bungee cord so no strain is placed on the brake hose. Do not let the caliper hang by the brake line.
4. 4

   Remove brake rotor
   With the caliper removed, slide the brake rotor off the hub. The rotor may be retained by one or more small set screws or may simply slide off. If the rotor is stuck due to corrosion, tap gently with a rubber mallet on the outer edge while rotating. Do not strike the friction surface. Once removed, inspect the hub area. Note whether an internal parking brake drum and shoes are present (drum-in-hat design) or whether the parking brake is actuated through the rear caliper, as the 1992 Viper may use a caliper-integrated mechanical parking brake.
5. 5

   Inspect parking brake shoes and mechanism
   Examine the parking brake shoes inside the drum area. Check for: excessive wear (shoes less than 1/8 inch thick at thinnest point), cracking, oil contamination, or glazing. Inspect the shoe return springs for rust or damage. Check the adjuster mechanism (star wheel) for corrosion or seizure. Verify cable attachment points are not broken or worn. Clean all components with brake cleaner and allow to dry.
6. 6

   Inspect parking brake cable
   Follow the parking brake cable from the backing plate toward the center of the vehicle. Check for: fraying of the cable strands, corrosion, kinks, or damage to the cable housing. Operate the parking brake lever inside the vehicle (have an assistant help) and watch for smooth cable movement. The cable should move freely without binding. If the cable is seized, frozen, or damaged, it must be replaced.
7. 7

   Service or replace parking brake shoes if needed
   If shoes are worn or damaged, remove the shoe hold-down springs using needle-nose pliers or a brake spring tool. Note the orientation of all springs and hardware before removal. Remove the adjuster star wheel assembly. Disconnect the parking brake cable from the actuating lever. Install new shoes in reverse order, ensuring the cable is properly connected and all springs are correctly positioned. Apply a small amount of high-temperature brake lubricant to the shoe contact points on the backing plate (6 raised pads).
8. 8

   Adjust parking brake shoes
   Locate the adjuster star wheel access hole in the backing plate or rotor mounting surface. Using a brake adjustment tool or flat screwdriver, rotate the star wheel to expand the shoes until they contact the drum surface and create drag. Then back off the adjuster until the drum rotates freely with only slight drag, per the factory service manual specification. Repeat this process on both sides to ensure equal adjustment.
9. 9

   Reinstall brake rotors
   Clean the hub mounting surface and rotor mounting surface with brake cleaner to remove any rust or debris. Slide the rotor back onto the hub, ensuring it seats fully. If the rotor had set screws, reinstall them finger-tight (they only retain the rotor during assembly; the wheel holds it in service).
10. 10

    Reinstall brake calipers
    Remove the caliper from its support wire and position it over the rotor. Install the caliper mounting bolts and torque to specification. Ensure the brake pads are properly seated on both sides of the rotor. Pump the brake pedal several times to restore hydraulic pressure before moving the vehicle.
11. 11

    Test parking brake cable operation
    With the rear wheels still off, have an assistant inside the vehicle operate the parking brake lever through its full range of motion. Watch the cable movement at the rear backing plates. The cable should move smoothly and the shoes should expand evenly against the drum. The lever should achieve full engagement within the number of clicks specified in the factory service manual. If more clicks are required, further adjustment is needed.
12. 12

    Adjust parking brake cable tension
    If parking brake engagement requires excessive lever travel, adjust the cable tension at the equalizer under the vehicle. The cable equalizer is located beneath the transmission tunnel area. Locate the threaded adjuster nut on the cable equalizer rod. Tighten the adjuster nut to increase cable tension (fewer clicks for engagement) or loosen to decrease tension. Adjust until the parking brake lever achieves full engagement within the factory-specified number of clicks while still allowing the rear wheels to rotate freely when released.
13. 13

    Reinstall wheels and lower vehicle
    Install the rear wheels onto the hubs and start all lug nuts by hand. Tighten lug nuts in a star pattern until snug but not fully torqued. Carefully raise the vehicle slightly off the jack stands using the floor jack, remove the jack stands, and lower the vehicle to the ground. With the vehicle on the ground, torque the wheel lug nuts to specification in a star pattern.
    Torque spec

    Wheel Lug Nuts183 Nm (135 lb-ft)

Reassembly

1. Reassembly is covered in the procedure steps above as this is primarily a service and adjustment procedure
2. Ensure all brake hardware is properly installed with correct spring tension
3. Verify brake calipers are torqued to specification and brake hoses are not twisted or kinked
4. Double-check that parking brake lever releases completely and rear wheels rotate freely when disengaged

Verification

• With the vehicle on level ground and engine off, engage the parking brake lever fully. Attempt to push the vehicle backward and forward - it should not roll
• Release the parking brake and verify the rear wheels rotate freely by hand with no dragging
• Test drive the vehicle in a safe area at low speed and verify hydraulic brakes function normally with no pulsation or noise
• On a slight incline, engage the parking brake and verify it holds the vehicle without rolling. Test both forward and reverse inclines if possible
• Verify the parking brake warning light on the instrument cluster illuminates when the lever is engaged and goes out when fully released
• Listen for any rubbing or dragging noises from the rear wheels during driving with parking brake released

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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