Symptoms
- Brake pad wear indicator squealing at low speed, going away under firm braking
- Vibration through the steering wheel during medium-to-hard braking (warped rotor, not pad)
- Pedal sinks slowly during a long stoplight hold (master cylinder, not pad — but worth knowing)
- Visible pad material at or below 3mm through the caliper window
- Deep grooves or a fingernail-catching lip on the rotor face
- Brake dust accumulating heavily on only one front wheel (sticking slide pin)
Tools
Required
- Floor jack and jack standsStands under the frame rails — never trust just the jack
- 19mm socket or impactLug nuts
- 13mm socket + ratchetCaliper slide pin bolts
- 18mm or 11/16" socketCaliper bracket bolts
- Breaker barBracket bolts are usually corroded tight
- Torque wrench (10–100 ft-lb range)
- C-clamp or piston compressorTo push the caliper piston back
- Wire coat hanger or bungeeHang the caliper — never let it dangle on the hose
- Brake cleaner (at least one can)
- Silicone caliper slide pin grease
- Anti-seize compound
Nice to have
- Turkey basterPull old fluid from the reservoir before compressing the piston
- Impact gunFaster on the bracket bolts but a breaker bar works
- Brake hose clampOptional — keeps fluid in the line if you open a bleeder
Parts
Torque specs
| Fastener | Value | Notes |
|---|---|---|
| Caliper slide pin bolts | 30 ft-lb | Snug, not gorilla-tight — over-torquing deforms the pins |
| Caliper bracket bolts | 77 ft-lb | Critical — holds full braking force of the axle |
| Lug nuts | 95 ft-lb | Star pattern, in two passes |
| Bleeder screw | 11 ft-lb | Snug only — brass deforms easily |
Procedure
- 1
Park on level ground and chock the rear wheels.
Never work under a vehicle supported only by a jack.Set the parking brake. The XJ's rear drums hold the truck even with the front off the ground, but chocks are cheap insurance.
- 2
Break the lug nuts loose before lifting.
Crack each lug nut a quarter turn with the truck still on the ground — much easier than fighting a spinning wheel in the air.
- 3
Raise the front of the vehicle and support it on jack stands.
Stands go under the frame rails, not the suspension. Test the truck's weight on the stands before getting under it.Place stands behind the front wheels under the frame rails. Lower the truck onto the stands and remove the jack from under the vehicle if you're not actively using it.
- 4
Remove the front wheels.
Set them aside out of the way. Now is a good time to inspect the tire's inner sidewall for wear or cuts you can't see when the wheel is mounted.
- 5
Inspect what you've got.
Look at the pad thickness through the caliper window. Check the rotor for scoring, blue heat marks, or a tall outer lip. Spin the rotor and listen for grinding or rough bearing noise — if a wheel bearing is failing, do it before the brakes go back together.
- 6
Remove the two slide pin bolts on the back of the caliper.
Caliper slide pin bolts: 30 ft-lbUse a 13mm socket. The bolts thread into the slide pins from the inboard side of the caliper. These are usually not tight; if they fight you, hit them with penetrating oil and try again — don't strip the head with a stuck bit.
- 7
Lift the caliper off the rotor.
Do not let the caliper hang by the brake hose. The hose isn't rated for it and tears are invisible until they fail.Slide it straight off the pads, then rotate it upward. Hang the caliper from the coil spring with a wire coat hanger or short bungee.
- 8
Pull the old pads out of the bracket.
They sit in retaining clips on the top and bottom of the bracket. Note which way the pad with the wear indicator (the small metal tab) faces — usually inboard.
- 9
Compress the caliper piston.
Open the master cylinder reservoir cap and watch the fluid level. If it's near full, siphon some out with a turkey baster before compressing.Place an old pad against the piston face and use a C-clamp to push the piston back into its bore. Go slowly. Opening the caliper bleeder (catch the displaced fluid in a rag) while you compress is cleaner and avoids pushing old fluid backward through the ABS module on 1996+ trucks.
- 10
Remove the caliper bracket from the steering knuckle.
Caliper bracket bolts: 77 ft-lbTwo large bolts (11/16" or 18mm head) hold the bracket on. They are torqued tight and may need a breaker bar. Once the bracket is off, hang it next to the caliper — do not let it dangle on the brake line either.
- 11
Pull the old rotor off.
Do not pry against the wheel studs to free a rust-stuck rotor — they'll bend.Most rotors are held only by the wheel studs and a small retaining clip on one stud (you can cut the clip off and discard it; it's a factory assembly aid). If the rotor is rust-stuck, hit the rotor face between the studs with a dead-blow hammer.
- 12
Clean the hub face.
Wire-brush the mating surface where the new rotor will sit. Any rust scale here causes lateral runout, which feels like warped rotors a month later. Wipe the cleaned surface with brake cleaner.
- 13
Wipe the new rotor with brake cleaner on both faces.
New rotors ship with a thin oil coating to prevent rust. That coating will smoke, stink, and contaminate your new pads if you skip this step. Spray both faces and wipe with a clean rag until the rag comes back dry.
- 14
Apply a thin smear of anti-seize to the hub face only.
Not the lug studs. Not the rotor's friction surface. Just the small ring of metal where the rotor sits flush against the hub. This stops the rust-weld from re-forming for the next service.
- 15
Hang the new rotor on the studs.
Spin a lug nut on by hand to hold it in place while you work.
- 16
Reinstall the caliper bracket.
Caliper bracket bolts: 77 ft-lbTorque the two large bracket bolts to spec. These bolts hold the entire braking force of the front axle — use a torque wrench.
- 17
Clean and grease the slide pins.
Pull each slide pin out of the bracket, wipe it down, inspect the rubber boot for tears, and apply a thin coat of silicone caliper grease before sliding it back in. Dry or seized slide pins cause uneven pad wear and pulling. If a boot is torn, replace it — debris in the pin bore is the most common cause of premature pad wear on the XJ.
- 18
Install the new pads into the bracket.
Wear indicator goes inboard (toward the piston). Make sure each pad sits flat against its retaining clip with no rocking.
- 19
Lower the caliper back over the pads and rotor.
It should slide on without forcing. If it won't seat, the piston isn't compressed all the way — back it out, compress further, and try again.
- 20
Thread the slide pin bolts back in by hand first, then torque.
Caliper slide pin bolts: 30 ft-lbHand-start the threads before bringing the wrench in to avoid cross-threading. Snug, not gorilla-tight. Over-torquing deforms the slide pins.
- 21
Repeat on the other side.
Always do both fronts in the same session.
- 22
Top off the brake fluid reservoir.
Use DOT 3 (factory spec) or DOT 4. Never mix DOT 5 (silicone) into a DOT 3/4 system. If you opened a bleeder during piston compression, bleed that caliper now using the standard two-person pedal method.
- 23
Mount the wheels and torque the lug nuts in a star pattern.
Lug nuts: 95 ft-lbLower the truck. Final torque happens with all four wheels on the ground.
- 24
Pump the brake pedal several times before driving.
The first pedal stroke after caliper service is long and soft. Do not pull out of the driveway until the pedal is firm and high.Pump until the pedal is firm and high. If it never firms up, you have a fluid leak, an unbled caliper, or the piston wasn't compressed evenly.
- 25
Bed the new pads.
Drive to an empty road and do 8–10 medium-pressure stops from 40 mph down to 5 mph (don't fully stop). Then do 2–3 firmer stops from 60 mph down to 15 mph. Drive a few miles to cool the brakes — and do not park with your foot on the brake pedal during this cool-down, or you'll transfer pad material onto the rotor face in a single spot, which feels like a warped rotor forever after. Park with the hand brake instead.
Verify it worked
- Pedal is firm and high after 4–5 pumps from cold
- No fluid weeping at the caliper bleeder, hose fitting, or bracket
- Truck pulls straight under medium braking from 40 mph
- No grinding, no squeal during the bedding-in stops
- No vibration through the steering wheel after the first 100 miles
- Pad material visible behind the rotor edge looks even left vs. right
Common mistakes
- Letting the caliper hang by the brake hose. The hose isn't rated to carry that weight and internal tears are invisible until the hose fails on a downhill.
- Skipping the rotor-face wipe-down. New rotors ship with an oil coating that contaminates pads on first heat cycle.
- Buying the cheapest no-name rotor at the parts counter. They warp within a year, the steering wheel starts shaking, and you're back under the truck doing the job again.
- Parking with your foot on the brake during the bed-in cool-down. Pad material transfers to the rotor in a single spot and feels like a warped rotor forever after.
- Mixing pad brands or types across the axle. Causes pull under braking; the front-end alignment shop can't fix it.
- Not torquing the caliper bracket bolts to spec. The bracket carries the entire braking force of that axle.