🔧 GLA250 - Rear Brake Pad Replacement

You’ll remove the rear wheels, swing the rear brake calipers out of the way, replace the pads (and wear sensor if equipped), then reassemble and torque everything correctly. This matters because worn pads reduce stopping power and can damage the rotors if driven too far.

Assumption: Your GLA250 has rear disc brakes and an electronic parking brake (EPB). Steps below include both “no scan tool” and “scan tool” EPB paths.

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

---

⚠️ Safety & Precautions

• Work on a level surface and support the vehicle with jack stands before going under or pulling wheels.
• Do not press the brake pedal while a caliper is removed; the piston can pop out and leak brake fluid.
• Make sure the EPB is fully released before starting; EPB clamping force can damage parts if you disassemble while applied.
• Brake dust is unhealthy—use brake cleaner, not compressed air, to clean parts.
• Keep brake fluid off paint; it removes paint quickly.

---

🔧 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
• 17mm socket
• 1/2" drive breaker bar
• 1/2" drive torque wrench (20-200 Nm range)
• Ratchet (3/8" drive)
• Socket set (metric)
• Allen/hex bit set (metric)
• Flat trim/pry tool
• Small pick tool
• Needle-nose pliers
• Brake caliper piston compressor tool (specialty)
• Wire hook or bungee cord
• Brake cleaner
• Nitrile gloves
• Safety glasses
• Scan tool with EPB service mode (specialty)

---

🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Rear brake pad set - Qty: 1
• Rear brake pad wear sensor (if equipped) - Qty: 1
• Brake lubricant/anti-squeal paste - Qty: 1
• Brake hardware/clip kit (if not included with pads) - Qty: 1

---

📋 Before You Begin

• Park on level ground, shift to P, and make sure the EPB is released.
• Chock the front wheels using wheel chocks.
• Loosen rear wheel bolts slightly (before lifting) using a 17mm socket and breaker bar.
• If using a scan tool for EPB: connect it now and be ready to run EPB Service Mode (this retracts/releases EPB for service).

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Lift and secure the rear

• Use a floor jack (rated 3-ton minimum) to lift the rear at the proper jacking point.
• Place jack stands (rated 3-ton minimum) under the correct support points and lower the vehicle onto them.
• Confirm stability with a gentle push before removing wheels.

Step 2: Remove the rear wheels

• Remove the wheel bolts using a 17mm socket and ratchet.
• Set wheels aside flat so they can’t roll away.

Step 3: Put the parking brake into service position (two options)

• Option A (with scan tool): Use a scan tool with EPB service mode (specialty) and run the EPB rear brake service function so the EPB is fully released for pad service.
• Option B (no scan tool): Ensure the EPB is fully released and stays released (do not open/close doors repeatedly if your EPB auto-applies). Keep the key away from the car.

Step 4: Remove the caliper spring/retainer (if equipped)

• Use a flat trim/pry tool to carefully pry the external caliper spring/retainer out.
• Keep your hand over it—springs can pop outward.

Step 5: Remove the caliper guide bolts

• If there are plastic caps over the guide bolts, remove them using a small pick tool.
• Remove the caliper guide bolts using the correct size from your Allen/hex bit set (metric) with a ratchet (3/8" drive).
• Note bolt positions and keep them clean.

Step 6: Remove and support the caliper

• Lift the caliper off the bracket.
• Hang the caliper using a wire hook or bungee cord so it does not pull on the brake hose.

Step 7: Remove old pads and hardware

• Pull the inner and outer pads out of the bracket by hand. Use needle-nose pliers if they’re tight.
• Remove and replace any pad abutment clips/hardware if your new pad set includes them.
• If a wear sensor is present, disconnect it carefully using a small pick tool or needle-nose pliers (don’t yank the wire).

Step 8: Compress the caliper piston

• Before compressing, spray and wipe the area with brake cleaner.
• Use a brake caliper piston compressor tool (specialty) (this tool slowly pushes the piston back in evenly) to press the piston fully into the caliper.
• Check the brake fluid reservoir as you compress; fluid level may rise. Go slow to avoid overflow.

Step 9: Install new pads and sensor

• Apply a thin layer of brake lubricant/anti-squeal paste to the pad backing plates where they contact the caliper/bracket (keep lube off the pad friction material and rotor).
• Install new pads into the bracket.
• If equipped, install the new rear brake pad wear sensor and route the wire the same way as original.

Step 10: Reinstall the caliper and torque bolts

• Reposition the caliper over the new pads.
• Install the guide bolts by hand first to prevent cross-threading, then tighten using the correct Allen/hex bit and ratchet (3/8" drive).
• Tighten with a 1/2" drive torque wrench (20-200 Nm range): Torque to 30 Nm (22 ft-lbs) for the caliper guide bolts.
• Reinstall the caliper spring/retainer using a flat trim/pry tool if equipped.

Step 11: Reinstall wheels and torque lug bolts

• Reinstall wheels and hand-thread all wheel bolts.
• Lower the vehicle off the jack stands using the floor jack.
• Torque wheel bolts in a star pattern using a 17mm socket and torque wrench: Torque to 130 Nm (96 ft-lbs).

---

✅ After Repair

• Before driving, pump the brake pedal 10-15 times until it feels firm (this seats the pads against the rotors).
• Apply and release the EPB a few times to confirm normal operation.
• Road test at low speed first; confirm no grinding, pulling, or warning messages.
• Pad bedding (break-in): make 6-10 gentle stops from ~30 mph down to ~5 mph, with cooling time between. Avoid hard braking for the first 150-200 miles if possible.
• If the brake pad warning stays on after sensor replacement, re-check the sensor connection and wire routing.

---

💰 DIY vs Shop Cost

Shop Cost: $300-$650 (parts + labor)

DIY Cost: $60-$200 (parts only)

You Save: $240-$450 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.

---

🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.