2019-2020 Jeep Gladiator Brake Caliper Problems and Replacement

By Core Brake Parts Tech Team — Circleville, OH warehouse

Most brake caliper complaints on an early Jeep Gladiator (JT) come down to three things: a caliper that sticks and drags because its guide pins or piston have seized, a caliper that leaks fluid, or a click and clunk from the rear that FCA traced to loose or missing rear caliper adapter bolts. The adapter-bolt issue has its own factory bulletin and is often a warranty repair. A sticking or leaking caliper is fixed by rebuilding or replacing it, ideally as a pair on the same axle, then bleeding the system.

Below is how the Gladiator's calipers are built, how to tell which problem you have, and what to replace while you are in there.

How the Gladiator's Calipers Are Built

The Gladiator uses four-wheel vented disc brakes with ABS on every trim. According to FCA's 2020 Gladiator specification sheet, both axles use floating calipers: a twin-piston floating caliper up front and a single-piston floating caliper at the rear. Floating means the caliper body slides on two guide pins. The piston pushes the inner pad into the rotor, and the caliper body slides inward to pull the outer pad against the other face. That design is simple and reliable, but it only works if the guide pins slide freely.

The rear caliper bolts to the axle through a caliper adapter (the bracket), and the parking brake is not built into the rear caliper. FCA's rear axle shaft service notification for the JT describes disconnecting the park brake cable from the brake shoe lever before pulling the axle, which tells you the Gladiator parks on small drum-style shoes inside the rear rotor hat. That matters when you diagnose a rear drag: it can be the caliper or a parking brake shoe that is not releasing.

A note on years: parts catalogs often list Gladiator fitment as 2019 and newer, while the FCA bulletins covering these trucks list the JT Gladiator starting with the 2020 model year. The caliper hardware discussed here is the same either way.

Symptoms of a Bad Caliper on a Gladiator

Power Stop's caliper guide lists the classic signs, and they apply directly to this truck:

• Pulling to one side under braking, or a steady pull when cruising if one caliper is dragging.
• Uneven pad wear, with one pad on an axle, or the inner pad versus the outer pad, worn far more than the others.
• Brake fluid leaks or wetness on the inside of a wheel, the caliper body or the hose connection.
• A dragging feel, a hot wheel after a drive or a burning smell from one corner, which means the piston is not retracting.
• Noise such as squealing or grinding, and longer stopping distances.
• Visible corrosion or damage to the caliper body, boots or bleeder.

On a Gladiator there is one more symptom to add: a click or clunk from the rear. FCA service bulletin 05-006-21 lists exactly that complaint for 2020-2021 JT Gladiators and 2018-2021 JL Wranglers built on or before May 18, 2021, and traces it to rear caliper adapter bolts that are loose or missing.

Common Causes and How to Diagnose Them

Loose or missing rear caliper adapter bolts

This is the Gladiator-specific one, and it should be the first thing you check on a truck with a rear clunk. With the rear wheels off, look at the four bolts holding the two rear caliper adapters to the axle. The bulletin's rule is simple: if any of the four are loose or missing, all four are replaced with new bolts and tightened to 125 N-m (92 ft-lbs). If they are all tight, the bulletin does not apply and the noise is coming from somewhere else. A caliper adapter that works loose takes the caliper with it, so do not keep driving a truck with a missing adapter bolt.

Seized guide pins

If the pins stop sliding, the caliper can no longer center itself. You will usually see the inner pad worn much thinner than the outer one, or a tapered pad. Pull the pins, clean them and the bores, and check that the rubber boots are intact. A pin that is pitted, or a boot that is torn, should be replaced with a brake hardware kit.

Sticking or leaking piston

Corrosion on the piston, often behind a torn dust boot, keeps it from retracting. Raise the corner, have a helper press and release the pedal, and check whether the wheel spins freely afterward. Wetness around the piston boot or at the hose connection means a seal has failed. Either case calls for a rebuilt or new caliper.

Collapsed brake hose

A hose that has deteriorated inside can act like a one-way valve and hold pressure on the caliper. If a caliper releases as soon as you crack its bleeder, suspect the hose and replace it from our brake hose range.

Rear parking brake shoes

If a rear wheel drags but the caliper and pins check out, look at the parking brake shoes inside the rotor hat and the cable adjustment before buying a caliper you do not need.

The Fix: Replacing a Gladiator Caliper

A caliper swap on this truck is a manageable driveway job for someone who has changed pads before. The outline:

1. Loosen the lug nuts, raise the truck at a proper lift point and support it on stands, then remove the wheel.
2. Clamp or plug the brake hose, then disconnect the hose at the caliper.
3. Remove the guide pin bolts and the caliper. If you are also doing rotors, remove the caliper adapter.
4. Clean the adapter and abutment areas with a brass wire brush and brake parts cleaner. Fit new abutment clips if the old ones are rusted or bent, and grease the pad contact points with high-temperature brake grease.
5. Install the new caliper with new pads, using new crush washers on the hose fitting so it seals.
6. Torque every fastener to the values in the factory service manual. The rear caliper adapter bolts are 125 N-m (92 ft-lbs) per the FCA bulletin. Where the manual calls for thread locker, use it.
7. Bleed the brakes following the service manual procedure, then pump the pedal until it is firm before the truck moves.

Power Stop's installation tips put particular weight on steps 4, 5 and 6: a clean bracket, fresh crush washers and correctly torqued guide pin bolts separate a caliper job that lasts from one that squeaks or leaks. Use only the brake fluid type printed on your Gladiator's reservoir cap and in the owner's manual.

What to Replace at the Same Time

• The other caliper on the axle. Power Stop recommends replacing calipers in pairs so both sides clamp evenly and wear at the same rate. A new caliper next to a tired one can make the truck pull. Browse replacement brake calipers or the Cardone line.
• Pads on both sides of the axle. A dragging caliper usually cooks its pads. For the rear of a Gladiator we carry EBC Extra Duty rear pads (ED93093), EBC Yellowstuff rear pads (DP43093R) and Hawk LTS rear pads (HB944Y.745), built for trucks that tow and haul.
• Rotors if they are overheated, scored or below minimum thickness. The minimum thickness is stamped on the rotor. For the front we offer EBC GD Sport slotted front rotors (GD7815), plus the full brake rotor selection.
• Guide pins, boots and clips from a hardware kit, since they are inexpensive and are the root cause of most sticking.
• Brake fluid. A caliper job means bleeding anyway, and flushing the whole system at the same time removes the moisture that corrodes pistons in the first place.

How Hard Is the Job?

For a caliper-only swap on one axle, plan on a few hours in a driveway with hand tools, a torque wrench, hose clamps and a way to bleed the brakes. The Gladiator's size works in your favor: the wheels are big and heavy, but there is plenty of room around the calipers. The parts that trip people up are the adapter bolts, which are tight and must be torqued correctly, and bleeding, which must be done completely before the truck is driven. If you are not comfortable bleeding brakes, have a shop finish the job. If your truck is a 2020 or 2021 built before the bulletin cutoff and has the rear clunk, ask a Jeep dealer first, because FCA lists the adapter-bolt repair as reimbursable within the provisions of the warranty.

Frequently Asked Questions

What causes a clunk from the rear brakes of a Jeep Gladiator?

On 2020-2021 Gladiators built on or before May 18, 2021, FCA bulletin 05-006-21 identifies loose or missing rear caliper adapter bolts as a cause of a click or clunk from the rear. If any of the four bolts are loose or missing, all four are replaced.

Should I replace Gladiator calipers in pairs?

Yes. Replacing both calipers on the same axle keeps clamping force even from side to side, so the truck stops straight and both sets of pads wear at the same rate.

Can I just rebuild a sticking caliper?

If the bore and piston are clean and undamaged, a seal and boot kit can work. If the piston is pitted or the bore is corroded, a rebuilt or new caliper is the reliable fix and saves time.

Does the Gladiator have an electronic parking brake in the rear caliper?

No. The rear calipers are single-piston floating calipers, and the parking brake uses shoes inside the rear rotor hat operated by a cable, so a rear caliper can be changed without a scan-tool service mode.

Do I need new pads when I replace a caliper?

Almost always. A caliper that dragged has overheated its pads, and fresh pads on both sides of the axle give the new calipers an even surface to work against. Check the rotors at the same time.

Sources

1. FCA US 2020 Jeep Gladiator Specifications - rotor sizes, twin-piston front and single-piston rear floating calipers, ABS standard
2. FCA Service Bulletin 05-006-21 (NHTSA) - rear caliper adapter bolts loose or missing, affected builds, 125 N-m torque, warranty policy
3. FCA Customer Satisfaction Notification 26A, JT Gladiator (NHTSA) - rear caliper removed with adapter, park brake cable at the brake shoe lever
4. Power Stop - When Should I Replace Brake Calipers - failure symptoms, replacing calipers in pairs
5. Power Stop - Tips for Installing a New Brake Caliper - bracket cleaning, crush washers, guide pin torque, bleeding