1970-1978 GMC Jimmy Parking Brake Cable: A Complete Replacement Guide
Don't let a snapped or stretched cable compromise the safety of your classic Jimmy; here's what you need to know.
- Your Jimmy uses a multi-part system; you must identify if the front, intermediate, or rear cable has failed before buying a replacement.
- New aftermarket cables from a brand like Dorman are the most practical and reliable solution, as new OEM parts are unavailable.
- A snapped cable will cause the pedal to go to the floor with a 'pop', while a stretched cable will feel loose and won't hold the truck securely.
- Replacing the cables is a feasible DIY job, and cutting the old, rusted cable out is often the easiest removal method.
Is Your Parking Brake Cable Failing?
On a classic truck like the GMC Jimmy, the parking brake cables are constantly exposed to moisture, road salt, and dirt. After decades of service, these steel cables will rust, stretch, and eventually break. Knowing the signs of failure is key to preventing a dangerous roll-away situation.
Common Failure Symptoms
- Pedal Goes to the Floor: You press the parking brake pedal and it offers no resistance, dropping straight to the floor, often with a loud "pop" sound. This almost always means a cable has snapped.
- Loose or Spongy Pedal: The pedal feels mushy or doesn't fully return to its original position when released. This indicates a stretched or seizing cable.
- Truck Rolls When Parked: The most obvious sign. If you set the brake and the truck still moves, the cables are not holding tension.
- Failure to Pass Inspection: Many states require a functional parking brake to pass a vehicle safety inspection.
Choosing the Right Aftermarket Cable
For a vehicle from this era, finding new original equipment (OEM) parts from GM is not a realistic option. Your choices are essentially a used cable from a salvage yard or a new aftermarket cable. A used cable is not recommended, as it will be just as old and prone to failure as your current one. A new aftermarket cable is the safest and most reliable choice.
Your 1970-1978 Jimmy has a three-part system. You must first identify which cable has failed: the front (from pedal to frame), intermediate (connects front to rear), or rear (a pair of cables from the intermediate to each wheel). Sometimes it's best to replace all of them at once, especially if they are all original.
Available Brand: Dorman
Dorman is the most common brand for these replacement cables. Their products are engineered to match the original's fit and function. They feature a protective sheath to guard against corrosion and are lubricated internally to ensure smooth operation. For a simple mechanical part on a classic truck, Dorman is a widely accepted and reliable replacement option that restores original performance and safety.
Parking Brake Cable Replacement Cost for 1970-1978 GMC Jimmy
| Part/Service | Estimated Cost |
|---|---|
| New Aftermarket Cable (Dorman) | $27.53 - $85.58 (price is per cable; front, intermediate, and rear cables are sold separately) |
| Shop Labor | $150 - $300 |
| New OEM Cable | Not generally available |
A Note on Installation
Replacing these cables is a manageable DIY job for those with basic tools. The process involves removing the rear wheels and brake drums to access the cable connection. A common pro tip is to simply cut the old, rusted cable with wire cutters to make removal much easier. The new cable is then routed, connected, and finally adjusted at the equalizer nut to achieve the proper tension.
Frequently Asked Questions
How many parking brake cables does my Jimmy have?
Your truck uses a multi-cable system. Typically, this includes one front cable, one intermediate cable, and two rear cables (one for each rear wheel). You must identify which section is broken before ordering a replacement.
Can I just adjust a loose cable?
If the cable is simply loose from minor stretching, you can tighten it at the equalizer nut. However, if the pedal feels spongy or the cable is visibly frayed or rusted, adjustment is only a temporary fix at best. A compromised cable should always be replaced.
Is there a recall on my GMC Jimmy's parking brake cable?
No. There are no active NHTSA recalls for the parking brake cables on the 1970-1978 GMC Jimmy. Failures are due to the age and wear of the original parts.
Is it hard to replace a parking brake cable?
For a DIY mechanic, it's a moderately difficult job that requires safely lifting and supporting the vehicle. It involves removing the wheels and brake drums. The most difficult part is often dealing with rusted old parts, which is why cutting the old cable out is often recommended.
Technical Specifications
System consists of front, intermediate, and rear cables. Cables are steel, typically with a protective plastic or rubber coating.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.