Jeep Wrangler JK: Brakes Diagnostic Guide

Chris

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Nothing is worse than brake issues in the Jeep Wrangler. The brake system is the hardest working system in your Jeep Wrangler. Your brake system is a pressurized system that allows the brake calipers' pistons to clamp when you press the brake pedal, which creates friction when the pads clamp on the rotors and that's what stops your car. There are numerous things that can go wrong in your brake system, but the good news is diagnosing it isn't too difficult. This guide will go over some of the most common problems that can arise in your braking system. Read on to learn how you can diagnose the brakes in your Jeep Wrangler.

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Materials Needed
  • Jack and jack stands
  • Tire iron
  • Socket set
  • Flashlight
Step 1 – Check for leaks
Your brakes could be leaking.

A brake fluid leak will result in a spongy brake pedal. Also, air inside your pressurized brake system will also cause your brake pedal to feel spongy. If you feel the brake pedal feels strange or you notice the brake fluid reservoir is low on fluid, grab your flashlight and check the brake lines for leaks. Check under the car, on the connections between the brake caliper and brake line, then check the master cylinder for any signs of wetness. If you discover a leak coming from a brake line, replace the brake line and bleed your brakes.

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Figure 1. Check behind the caliper for brake line leak.

If there are no leaks, proceed to Step 2.

Step 2 – Check brake pads
They could be worn.

The brake pads get worn, that's their job. If you start hearing squealing when you step on the brake pedal, this means your pads are wearing. The louder the squealing, the worst it is. To check the brake pads, you will need to raise your Jeep and secure it on jack stands. Remove the wheel, remove the brake caliper's two rear bolts, and check the pads. The minimum brake pad thickness is 2-3mm. If it's too thin, replace it with new pads.

Alternatively, if you're suspecting a brake pad issue but the pads look within spec, actually pull them from the caliper and inspect the faces that contact the rotor. It is not unknown to have defective brake pads. Yours truly once snapped a pair of brake pads in half, causing a terrible braking vibration. They looked fine when they were in the caliper, but upon removal came out in pieces.

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Figure 2. Brake pads (old vs. new).

If the pads are thick enough, move on to Step 3.

Step 3 – Check rotors
They could be rusted, cracked, or grooved.

The brake rotors tend to go bad if you expose them to rough weather conditions for too long without using them, or if you continue to use your worn brake pads. Worn brake rotors will also result in squealing when braking, and they would affect your brake's performance. To check them, you can either look through the wheels for any grooves, cracks or rust, or you can remove the wheel and check them out. Replacing them is simple, you will need to remove the wheels and the brake calipers. Then tap them with a rubber mallet, pull it straight out, and install the new on in place.

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Figure 3. Heavily grooved and scored brake rotor.

If your brake rotors are in good condition, proceed to Step 4.

Step 4 – Check calipers
They could be sticking.

The calipers rarely ever need to be changed; however, there is always an exception to the rule. The caliper's piston can stick, which will result in constant friction between the pads and the rotors, even without pressing the brake pedal. This can wear out the brake pads and rotors very quickly and produce burning smell, along with squealing. To check that, look at the gap between the pads and the rotors without stepping on the brake pedal. If there is no gap, then your caliper needs replacement. To replace a brake caliper, you will need to remove it off of the rotor, disconnect the brake line and connecting it to the new caliper, then place the new caliper on top of the rotor and tighten its bolts. You will have to bleed your brakes, because removing the brake line allows air to alter the pressurized brake system.

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Figure 4. Sticking brake caliper.