Brake Job Walk-through (pad & rotor)

A brake job is one of the first big customer-pay tickets an apprentice owns. Customers feel every mistake through the pedal, so there is no room for sloppy work. This guide walks a front pad and rotor job start to finish on a typical passenger car. The same sequence applies to rear brakes with a few notes at the end for integrated parking brake calipers.

Pre-Job Setup

Look up torque specs before you break the first bolt

The shop service info (Mitchell, AllData, Identifix, or OEM portal) will give you four numbers you need written on your work order or on a sticky note on the fender:

Fastener                  Typical Range        Notes
------------------------  -------------------  ----------------------
Lug nuts                  80-100 ft-lbs        Verify by vehicle
Caliper slide pins        18-26 ft-lbs         Smaller fastener
Caliper bracket bolts     80-120 ft-lbs        Often TTY on Euro cars
Wheel speed sensor bolt   60-90 in-lbs         In inch-pounds, easy to strip

Some caliper bracket bolts are torque-to-yield (TTY) single-use. Check the service info. If the book says replace, replace. A TTY bolt reused is a caliper that walks off the knuckle on a freeway exit.

Parts check-in

Before the car comes in the bay, open every box:

• Pads (correct side, correct count, friction material intact)
• Rotors (correct part number matches the caliper type, vented vs solid, hat height)
• Hardware kit (abutment clips, anti-rattle springs, new slide pin boots if included)
• Brake fluid (correct DOT rating for the vehicle, factory sealed, dated)
• Caliper grease (silicone-based brake grease, not chassis grease, not copper anti-seize)

Wrong-side pads and mis-ordered rotors are the top parts-counter mistake. Five minutes at check-in saves forty minutes of re-pull.

Lift and wheel removal

Use the manufacturer lift points. Never lift on a control arm or a sway bar. Crack lug nuts on the ground, raise the car, remove the wheel, and keep the lug nuts in a tray. Inspect the hub face for rust mounds (we will come back to this).

Inspection Before Touching Wrenches

This is the step apprentices skip to feel fast and senior techs do first to be right.

Pad thickness

• New pads are 10-12mm of friction material on the backing plate
• 2mm or less is replace
• 3-4mm is worn and worth discussing with the customer
• Uneven wear across the set (inner 4mm, outer 8mm, or vice versa): stuck slider pin, stuck caliper piston, or a frozen outboard pad clip
• Tapered wear on one pad (thicker at the leading edge, thinner at the trailing edge): caliper bracket not square to the rotor or a bent bracket

Pull both pads out before making the call. One pad tells half the story.

Rotor condition

Measure with a micrometer. Compare to the minimum thickness stamped on the rotor hat or hub, not the rotor face. Typical front rotor minimums run 22-26mm depending on the car, but the number that matters is the one stamped on THIS rotor. Under minimum is always replace, never machine.

Check                     Typical Spec         Tool
------------------------  -------------------  -------------------------
Thickness                 Above min stamped    Outside micrometer
Runout (lateral)          0.003 in max         Dial indicator on hub
Parallelism / DTV         0.0005-0.001 in      Mic around the rotor
Surface condition         No mirror glaze      Visual
Heat / blue spots         None                 Visual

Mirror finish across the entire friction surface means the pad was not biting, usually because of a glazed pad or a stuck caliper. Blue heat spots or hard dark patches are hot-spotting - the rotor has changed microstructure and will pulse the pedal no matter how clean it looks. Replace it.

Deep scoring you can catch a fingernail in is replace. Hairline score lines are fine on a rotor that still has thickness.

Hardware and hydraulic

• Abutment clips (the stainless tin clips on the caliper bracket that pads slide against): corroded or missing means new clips in the kit
• Anti-rattle springs: bent springs cause that pebble-in-the-wheel rattle at low speed
• Slide pin boots: a torn boot means water sat on the pin and the pin is rusty inside the bore
• Caliper piston boot: if it is torn, the piston is rusted or getting there, and the caliper is a replace
• Flex brake hose: cracks in the outer sheath, bulges when the brakes are applied, or damp spots near the crimp are all replace

Caliper Removal

Push the piston back BEFORE you remove the caliper

This is the step apprentices reverse and then wonder why the new thicker pads will not fit over the new rotor.

On most front calipers: pull the caliper back from the bracket just enough to get a C-clamp or dedicated piston retraction tool on the piston face, using the old pad as a pressure spreader. Open the bleeder screw while retracting if the reservoir is already full (you do not want to push dirty fluid back up through the ABS module). Wait for the piston to travel flush.

On many rear calipers with integrated parking brake, DO NOT push the piston. It must be screwed in clockwise (or the direction specified by the service info) with the correct cube tool. Forcing a parking-brake rear piston straight in destroys the ratchet mechanism inside and turns a brake job into a caliper replacement.

Support the caliper

Hang the caliper from the coil spring or the strut with a wire hook, a bungee, or a purpose-made caliper hanger. Never let the caliper hang by the flex brake hose. Even one time will damage the internal crimp and cause a slow leak later.

Caliper and Bracket Service

1. Remove the slide pins. They should come out smoothly with a firm pull. If they are rusted in, the bore is corroded and the caliper may need a rebuild or replacement.
2. Wire-brush the slide pin bores clean. Do not ream them - the finish matters.
3. Install new rubber boots from the kit if supplied, or reuse if they are intact.
4. Pack the slide pin and the bore with a thin film of silicone brake grease. NOT lithium chassis grease, NOT copper anti-seize. The silicone compatibility is required so rubber boots do not swell and pins do not bind in heat.
5. Reinstall the pins and stroke them by hand. They should slide smoothly against finger pressure, no drag, no clicking.

Check the caliper piston boot one more time under good light. A tear means replace the caliper.

Rotor Removal

Most rotors are held by one or two small retaining screws (Allen or Torx) in the rotor hat. Remove those with the correct impact-rated bit. If the screws are stripped, drill them out carefully and note it on the ticket so you can replace them at install.

Once the screws are out the rotor should slide off. In rust-belt cars it will be corrosion-welded to the hub. Two tricks:

• The threaded-hole trick. Many rotors have a pair of tapped holes in the hat sized for an M8 bolt. Spin an M8 bolt in each hole and it will walk the rotor off the hub surface.
• The mallet trick. A heavy dead-blow or rubber mallet on the rotor hat (between the wheel studs) will break the bond. NEVER hit the friction surface - you can crack a cast iron rotor or knock a stud loose.

New Rotor Prep

New rotors come coated in a waxy shipping oil that prevents rust in the box. It is not brake-safe. Spray both sides thoroughly with brake clean (not carb clean, not aerosol wheel cleaner) and wipe with a clean lint-free rag until the rag comes away clean.

Inspect the hub face. This is the single most important thing you do on a brake job for long-term pedal quality. Any rust bump on the hub face will sit between the hub and the rotor hat and create lateral runout. 0.003 inch of runout is enough to feel as pedal pulsation within a thousand miles. Use a wire wheel or a dedicated hub-face cleaning disc on a die grinder until the face is bright metal. Wipe with brake clean.

Install the rotor. Install the retaining screw(s) and torque to spec (usually just hand-tight plus a firm turn - these are locating screws, not structural).

Pad Install

1. Remove the old abutment clips from the caliper bracket. Wire-brush the bracket seats clean.
2. Install new abutment clips from the hardware kit. They snap into place. Clips missing from the bracket is the top apprentice oversight on a brake job.
3. Install any anti-rattle springs that came with the pad kit.
4. Apply a thin film of silicone caliper grease to the pad backing plate at the contact points where the piston and caliper fingers press, and to the ears of the pad where it sits in the abutment clips. Do NOT put grease on the friction material. Some modern pads specifically prohibit any grease on the backing plate - read the box before reaching for the tube.
5. Seat the pads in the bracket.
6. Reinstall the caliper over the pads. The piston should clear the new pad thickness because you retracted it earlier.
7. Install the slide pin bolts and torque to spec (typically 18-26 ft-lbs).
8. If you removed bracket bolts, install them dry (unless the service info specifies thread locker) and torque to spec (typically 80-120 ft-lbs, confirm per vehicle, and replace if TTY).

Bleeding If You Opened the System

If you cracked a bleeder, disconnected a line, or let the reservoir run dry, you need to bleed.

• Use a flare wrench on the bleeder. An open-end wrench will round the corners.
• Pump-pause-crack with a helper: pedal down, crack bleeder, close bleeder, pedal up. Repeat until clean fluid with no air.
• Or use a vacuum/pressure bleeder at the reservoir and a clear hose at each bleeder until the bubbles stop.
• Track the reservoir level every few pumps. Letting it run dry pulls air back into the master and you start over.
• On ABS-equipped cars with trapped air, a scan tool can cycle the ABS module valves to purge air from the HCU. Use the function when symptoms demand it.

Always top the reservoir with fresh sealed fluid of the correct DOT rating. Old brake fluid is hygroscopic, corrosive to paint, and toxic. Collect it in a waste container and send it out with hazardous disposal, not down the floor drain.

Burnish / Bed-In

New pads need a transfer layer laid down on the new rotor. The stopping power of a brake comes from a thin film of pad material deposited evenly on the rotor surface that the pad then grips against. Without bed-in, pads grab unevenly and glaze.

Manufacturer-specific procedures vary. A common routine:

• 20-30 moderate stops from 30 mph down to about 5 mph, not to a full stop
• Let the brakes cool for a few minutes at highway speed between sets
• Finish with a handful of harder stops from 50 mph down to 20 mph, again not to a full stop
• Park and let the rotors cool without the pads sitting hot against the surface (which would leave an uneven deposit)

Tell the customer what you did and instruct them to avoid panic stops from highway speed for the first 200 miles.

Road Test

Every brake job gets a road test:

• Pedal feel firm within one full pump
• No pedal pulsation at cruise or deceleration
• No pull left or right under moderate braking
• No grinding, chirping, or squealing
• Parking brake holds on an incline

If the pedal pulses, the first suspect is rotor runout from a dirty hub face. Pull the wheel and remeasure with a dial indicator on the rotor face. If the pedal is spongy, you have air in the system - bleed again.

Safety and Closeout

• Never reinstall a lug nut cross-threaded. Start every lug by hand.
• Torque lug nuts in a star pattern, in two passes, with the car back on the ground.
• Reset the maintenance reminder if the vehicle has one.
• Note pad and rotor part numbers and measurements on the work order.
• Dispose of old fluid through the shop hazardous waste stream.
• Wipe the wheels before handing the keys back. The customer does not see the work, they see the wheels.

Brake work rewards discipline. Do every step in order every time and you build the habit that makes the second hundred brake jobs faster than the first.