🔧 GS - Rear Brake Pad Replacement

You’ll remove the rear wheels, swing the rear brake calipers up, swap the old pads for new ones, then reassemble and torque everything correctly. The key is retracting (pushing back) the caliper piston so the thicker new pads fit and making sure the parking brake is fully released.

Difficulty Level: Intermediate | Estimated Time: 1.5-3.0 hours

Assumption: Your GS may have either a mechanical parking brake or an electronic parking brake (EPB); steps below include both paths.

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⚠️ Safety & Precautions

• 🛑 Support the car on jack stands—never rely on a jack alone.
• 🧤 Brake dust is harmful—wear nitrile gloves and a dust mask; avoid blowing dust with compressed air.
• 🔥 Brakes can be hot—let the rear brakes cool before touching parts.
• ⚠️ Do not press the brake pedal with a caliper removed.
• 🔌 If your GS has EPB, put it in service/maintenance mode before pushing pistons back (forcing it can damage the EPB actuator).

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🔧 Required Tools

You'll need the following tools for this repair:

• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• 21mm socket
• Breaker bar (1/2" drive)
• Torque wrench (10-200 Nm range)
• 14mm socket
• 17mm socket
• Ratchet (3/8" drive)
• Flathead screwdriver
• C-clamp brake piston compressor
• Wire brush
• Brake cleaner spray
• Bungee cord
• Nitrile gloves
• Safety glasses
• Dust mask
• Scan tool with EPB service mode (specialty)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Rear brake pad set - Qty: 1
• Rear brake pad hardware kit - Qty: 1
• Brake caliper grease (silicone) - Qty: 1
• Brake cleaner - Qty: 1

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📋 Before You Begin

• Park on level ground, put the shifter in P, and chock the front wheels with wheel chocks.
• Release the parking brake fully before lifting the rear.
• Open the hood and locate the brake fluid reservoir; as pistons retract, fluid level may rise—do not overfill.
• If equipped with EPB: set EPB to service/maintenance mode before compressing pistons.
  • A scan tool with EPB service mode is the safest method (it commands the parking brake motors to retract).

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Loosen lug nuts (before lifting)

• Use a 21mm socket with a breaker bar to loosen the rear wheel lug nuts about 1/2 turn.

Step 2: Lift and support the rear

• Use a floor jack (rated 3-ton minimum) at the rear jacking point and raise the car.
• Place jack stands (rated 3-ton minimum) under the rear support points and lower the car onto them.
• Give the car a firm shake to confirm it’s stable.

Step 3: Remove both rear wheels

• Use a 21mm socket and ratchet (3/8" drive) to remove lug nuts.
• Remove both rear wheels and set them aside.

Step 4: If equipped, set the EPB to service/maintenance mode

• If your GS has an electronic parking brake switch (button), use a scan tool with EPB service mode (specialty) to retract the EPB.
• EPB service mode prevents actuator damage.

Step 5: Remove the rear caliper slide bolts

• Turn the steering wheel is not needed for rear; position yourself for access.
• Use a 14mm socket with a ratchet (3/8" drive) to remove the two caliper slide bolts.
• Carefully swing the caliper up and off the pads.
• Support the caliper with a bungee cord so it doesn’t hang by the brake hose.

Step 6: Remove old pads and hardware

• Pull the pads out by hand; use a flathead screwdriver gently if they’re stuck.
• Remove the pad clips/hardware from the caliper bracket.
• Use brake cleaner spray to clean the bracket areas (avoid spraying directly into your face).
• Use a wire brush to remove rust where the pad clips sit.

Step 7: Retract (push back) the caliper piston

• Check brake fluid level at the reservoir first (it may rise).
• Place an old pad against the piston face, then use a C-clamp brake piston compressor to slowly compress the piston until fully seated.
• Compress slowly to avoid fluid overflow.

Step 8: Install new hardware and pads

• Install the new pad clips from the rear brake pad hardware kit.
• Apply a thin layer of brake caliper grease (silicone) to pad ears where they contact the clips.
• Install the new pads in the bracket (make sure they slide freely).

Step 9: Reinstall the caliper

• Swing the caliper back over the new pads.
• Install the caliper slide bolts by hand first to avoid cross-threading, then tighten with a 14mm socket.
• Torque to 25 Nm (18 ft-lbs) using a torque wrench (10-200 Nm range).

Step 10: If removed, reinstall caliper bracket bolts (only if you took the bracket off)

• If you removed the caliper bracket, reinstall the bracket bolts using a 17mm socket.
• Torque to 79 Nm (58 ft-lbs) using a torque wrench (10-200 Nm range).

Step 11: Reinstall wheels and torque lug nuts

• Reinstall wheels and hand-thread lug nuts.
• Lower the car off the jack stands using the floor jack.
• Torque lug nuts in a star pattern using a 21mm socket and torque wrench (10-200 Nm range).
• Torque to 103 Nm (76 ft-lbs).

Step 12: Restore EPB from service mode (if applicable)

• If your GS has EPB and you used service mode, exit service mode using the scan tool with EPB service mode (specialty).
• Apply and release the parking brake to confirm normal operation.

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✅ After Repair

• Pump the brake pedal 8–15 times before driving until it feels firm (this seats the pads against the rotors).
• Check brake fluid level and top up only if needed.
• Road test at low speed first; confirm no pulling, grinding, or warning lights.
• Pad bed-in (break-in): make 6–10 smooth stops from 30–10 mph, with cooling time between stops; avoid hard braking for the first 200 miles.

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💰 DIY vs Shop Cost

Shop Cost: $300-$550 (parts + labor)

DIY Cost: $60-$180 (parts only)

You Save: $240-$370 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-2.5 hours.

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🎯 Ready to get started?

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