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How to Diagnose a Failing Emergency Brake

When it comes to off-road driving, your truck’s braking performance is extremely important. Not only when controlling your truck on steep or rocky sections, but also when you are parked.

When your emergency brake (also called e-brake) fails, it can make some off-road situations pretty dangerous. For instance, if you winching somebody, or are an anchor point, your transmission should be in neutral if it is an automatic. That is to prevent damage to the transmission, of course. But that also means that your e-brake has to be up to the job. That’s why it’s important to check your e-brake system as soon as you suspect that your e-brakes are failing.

This guide will walk you through the process of thoroughly checking the entire system for problems.

What Happens When an Emergency Brake Fails?

A failed e-brake means that your truck won’t stay in place when you apply the e-brake. This can be dangerous, especially if you rely heavily on your e-brake. A good way to tell if your e-brake is failing is to observe your truck on non-level ground after applying the e-brake. If your truck moves, then the e-brake is likely bad. Another clear sign that the e-brake is bad is if the emergency brake light in the dash comes on. (Only on some vehicles.)

If your truck rolls while in park, it can damage your automatic transmission. Your transmission has a parking pawl inside it. The pawl isn’t strong enough to hold the vehicle in place under heavy loads, which is why your truck has an e-brake. If the e-brake is broken or too weak to hold the truck in place, the truck will move while in park if gravity pulls it down an incline or if winching. When that happens, the pawl can break. A broken pawl can seriously damage the transmission, and you may end up needing a new transmission.

What Could Cause an Emergency Brake to Fail?

You can attribute emergency brake failure to a number of factors. For example:

  • The cable could be cut, worn out, or stretched. When this happens, the cable is no longer tight enough to deliver enough pressure to the drum brake shoes or disc emergency brake pads to hold the truck in place.
  • Sometimes it’s just because the drum brake shoes or the emergency brake pads are worn. Pads that are worn can no longer provide enough grip to keep the truck in place.

In order to find out what’s wrong with your e-brake, you need to inspect three different parts:

  1. Parking lever or pedal
  2. Parking brake cable
  3. Rear drum shoes or brake pads

Below you’ll find instructions on thoroughly inspecting each part.

Inspecting the Parking Lever or Pedal

Park pedal
Image Credit: Persh

Sometimes the parking lever or pedal is just stuck in place and it affects the operation of the emergency brake. This can happen from lack of use. Stuck emergency brakes are pretty easy to identify and fix, fortunately. You want to see if the parking lever or pedal needs to be adjusted or unstuck. To do this:

  1. Park your truck on flat ground. Put the transmission in park (if it’s automatic) or in first gear (if it’s manual).
  2. Secure the rear tires with wheel chocks and then engage the parking brake.
  3. Find the parking brake lever or pedal and then gently wiggle it to see if it’s stuck. If it’s stuck, it’s possible that the hinges are rusted or the pins are broken.
  4. Check the parking brake cable attachment on the back of the lever or pedal to see if it’s broken or frayed. If there’s a bolt attached, see if the nut came loose. Use an emergency brake cable tool if necessary.
  5. Try to reset the parking lever or pedal. If there’s an adjuster on the lever, try to turn it.

Inspecting the Parking Brake Cable

Cable
Image Credit: TheDieselStop

You want to see if the parking brake cable is still in good shape. If it’s cut, stretched out, or worn, then the parking brake system can’t do its job.

  1. Park your truck on flat ground. Put the transmission in park (if it’s automatic) or in first gear (if it’s manual).
  2. Secure the rear tires with wheel chocks and then engage the parking brake.
  3. Lift the truck with a floor jack or jack stands.
  4. Find the parking brake cable and then visually inspect it along the undercarriage for any stretched areas, cuts, or excessive wear.
  5. Check all of the bolts and mounts to see if any of them came loose.
  6. Inspect the connections where the parking brake cable meets the rear brakes for any signs of damage.

Inspecting the Rear Drum Shoes or Brake Pads

Shoes

Sometimes a parking brake doesn’t work simply because the rear brake drum shoes have worn out. To check the brake drum shoes, take the following steps:

  1. Park your truck on flat ground. Put the transmission in park (if it’s automatic) or in first gear (if it’s manual).
  2. Loosen the lug nuts on the rear wheels. Do not remove them yet.
  3. Raise the truck with a floor jack and jack stands.
  4. Remove the lug nuts on the rear wheels and then take off the wheels.
  5. If your truck has rear drum brakes:
    1. With a sledgehammer, hit the side of the drum to free it up from the wheel studs. Be sure not to hit the studs.
    2. Remove the drums.
    3. Check the condition of the rear brake shoes. If the shoes are broken or worn, replace them as soon as possible.
  6. If your truck has rear disc brakes, remove the caliper and then check the pads for any wear. If your truck has rear disc brakes but a drum parking brake, you need to remove the disc brakes and the rotor in order to access the drum parking brake.