What socket do I need to change brake pads?

You’ll typically need a 13–15 mm socket for the caliper guide/slide bolts and a 17–19 mm socket for the caliper bracket bolts; many cars also use a 6–8 mm hex (Allen) or Torx T45–T55 bit for the slide pins. Wheel lugs are commonly 19–22 mm. Exact sizes vary by make, model, and year, so verify against your vehicle’s service information before starting.

What you’re actually loosening when you change pads

Replacing pads usually involves removing two sets of fasteners: the smaller guide/slide-pin bolts that let the caliper swing open, and the larger caliper bracket-to-knuckle bolts if you’re pulling the bracket off (often necessary to remove the rotor or for extra access). You’ll also remove the wheel lugs, and you may crack the bleeder screw for pushing pistons back. Some vehicles have a rotor-retaining screw as well.

Common socket and bit sizes by fastener

The following are the sizes you’re most likely to encounter when doing a pad swap. Bring a full metric set and a few common bits to avoid mid-job runs to the store.

• Wheel lug nuts/bolts: 17–22 mm (19 mm very common on many cars; 21–22 mm common on trucks/SUVs). Some older vehicles use 3/4 in SAE.
• Caliper slide/guide-pin bolts: 13, 14, or 15 mm hex heads are common. Many European and some domestic cars use internal hex (Allen) 6, 7, or 8 mm; older GM often uses 3/8 in Allen. Some models use Torx T45 or T50.
• Caliper bracket-to-knuckle bolts: 17, 18, or 19 mm on most cars; 21–22 mm on larger trucks/SUVs.
• Bleeder screws: 8–11 mm (10 mm is very common); some older domestic applications use 3/8 in. Use a 6-point or a flare-nut wrench to avoid rounding.
• Rotor retaining screw (if fitted): Torx T30/T40 or Phillips/JIS; an impact driver helps prevent cam-out.
• Brake hose banjo bolt (only if disconnecting hose): commonly 12–14 mm, but confirm before loosening.

Not every vehicle will use all of these fasteners, and some special editions or performance packages can differ. Checking your exact model’s service manual is the surest way to confirm sizes.

Quick picks by vehicle type (typical, not universal)

While you should verify specifics, these patterns cover many modern vehicles sold through 2025.

• Honda/Toyota/Nissan: 14 mm slide bolts; 17 or 19 mm bracket bolts; 19 mm wheel lugs.
• VW/Audi/BMW/Mercedes: 7 or 8 mm internal hex slide pins; 18 or 19 mm bracket bolts; 17 mm wheel lug bolts on many German cars.
• Ford/GM/Chrysler cars: 13 or 15 mm slide bolts (some GM use T50); 18 mm bracket bolts; 19–21 mm lugs.
• Full-size trucks/SUVs (F-150, Silverado/Sierra, Ram, etc.): 13–15 mm slide bolts or T50; 18–22 mm bracket bolts; 21–22 mm lugs.

Use these as starting points only. Trim levels, brake package upgrades, and regional variations can change fastener types and sizes.

How to identify the right socket without guessing

To avoid rounding fasteners or getting stuck mid-job, use a simple, methodical approach to size identification.

1. Clean the bolt head with a wire brush and brake cleaner so markings and edges are visible.
2. Test-fit a 6-point socket that seats fully with no wobble; step up or down a size until it’s snug. For internal-drive fasteners, determine if it’s hex (Allen) or Torx and match precisely.
3. If a slide pin spins, use the flats on the pin body (often 15–17 mm) to hold it with a wrench while loosening the bolt.
4. Use a breaker bar for bracket bolts and keep the socket square to the fastener to prevent rounding.
5. If it feels wrong (slipping or cocked), stop and reassess—don’t force it.

This quick check prevents damage and ensures you select the correct tool for each fastener.

Tools you’ll likely need in addition to sockets

Brake pad jobs often require more than a single socket. Having the following on hand will make the job smoother and safer.

• Ratchets and torque wrenches: 3/8 in drive for caliper hardware; 1/2 in drive for bracket bolts and lugs; breaker bar for stubborn bolts.
• Bit sets: Hex (Allen) 6–8 mm; Torx T30/T45/T50/T55; E-Torx (E12/E14) on some applications.
• Piston tools: C-clamp or piston compressor; wind-back tool for rear calipers with integrated parking brake mechanisms.
• Electric parking brake (EPB) service: OBD scan tool or vehicle-specific “service mode” procedure to retract EPB safely.
• Chemicals and care: Brake cleaner; high-temp brake grease for slide pins and pad ears; thread locker where specified; anti-seize on the hub face (never on lug threads).
• Support and safety: Caliper hanger/bungee, wire brush, flare-nut wrench for bleeders, gloves, eye protection, jack stands, and wheel chocks.

Arriving prepared with these tools reduces the risk of delays, damage, or unsafe reassembly.

Typical torque ranges (check your service manual)

Correct torque prevents loose hardware and avoids stripping threads. The exact spec varies; use the ranges below only as general guidance and confirm for your VIN.

• Caliper slide/guide-pin bolts: 20–35 ft-lb (27–47 N·m).
• Caliper bracket-to-knuckle bolts: 65–90 ft-lb (88–122 N·m) on cars; up to 120–150 ft-lb (163–203 N·m) on trucks/SUVs.
• Wheel lug nuts/bolts: 80–100 ft-lb (108–136 N·m) on most cars; 100–150 ft-lb (136–203 N·m) on trucks/SUVs.

Always use a calibrated torque wrench and follow the manufacturer’s specifications and tightening sequence.

When you’ll need more than a socket

A few scenarios require special procedures or tools beyond standard sockets and bits.

• Rear calipers with integrated parking brake: Use a wind-back tool to rotate and retract the piston; forcing it straight in can cause damage.
• Vehicles with electric parking brakes: Put the system in maintenance/service mode with a scan tool or the OEM procedure to avoid burning out the EPB motor.
• Stubborn hardware: Penetrating oil and controlled heat can help with seized bolts; an impact driver is useful for rotor retaining screws.

Planning for these cases prevents broken parts and ensures a safe, complete brake service.

Bottom line

For most pad jobs, bring a metric socket set covering 10–21 mm, plus 6–8 mm hex and Torx T45–T55 bits. Expect 13–15 mm for caliper slide bolts, 17–19 mm for bracket bolts, and 19–22 mm for lugs. Verify your exact sizes and torque specs in the service manual for your specific make, model, and year.

Summary

You’ll usually use 13–15 mm sockets for caliper slide bolts and 17–19 mm for caliper brackets, with 6–8 mm hex or T45–T55 Torx bits common on many models. Wheel lugs are typically 19–22 mm. Because hardware varies widely, confirm by test-fitting and consult your vehicle’s service information, especially for torque specs and EPB procedures.

What tool is needed to change brake pads?

As far as tools, you’ll want to round up a jack and jack stands, a lug wrench, C-clamp or caliper spreader tool, and a basic tool set. Many calipers require a Torx or Allen bit to remove the caliper bolts, so check to make sure that you have the correct tool before beginning the job.

What is the 30 30 30 rule for brakes?

At ADVICS, our technicians follow the 30-30-30 rule for bedding-in and suggest this as the preferred method. That means performing 30 slow stops from 30 mph, with at least 30 seconds of cool down in between.

What size socket for brake rotors?

To remove front brake rotors, typically a 13mm or 15mm socket is needed for caliper bolts, but sizes vary by vehicle. Use a breaker bar for stubborn bolts. After removing caliper bolts, support the caliper to avoid strain on brake lines. If the rotor is stuck, gently tap with a rubber mallet to loosen rust bonds.

What sockets do you use to change brake pads?

Allen Wrenches, Hex Keys, Torx and Allen Sockets
Torx sockets have a 6-sided star-shape on the business end and sizes range from very small (0.031”) to almost an inch.