Out with the Old and In with the New
Every so often, your disc brake pads just need to be replaced. Plus, you might need to replace them if you’re doing a drum to disc conversion and get spindles, rotors, and/or calipers from a donor car or the junkyard. Each of the Big Three does things a little differently down here, so we’re going to describe the differences and go over some tricks for each. I highly recommend a Chilton or Haynes Auto Repair manual for this process, though, to confirm all of the difference. If your car didn’t come stock with disc brakes, you need to get the manual for the car the brakes came off of.
I’m choosing one representative year, make, and model from some typical donor cars for classic car disc brake conversions to use as examples. These are:
- 1974 Chevy Camaro/Pontiac Firebird
- Ford Mustang or Pinto from the mid to late 70s
- 1974 Dodge Dart/Plymouth Duster
The List of Tools, Equipment, and Parts You’ll Need
- A jack
- At least one jack stand
- Lug wrench or tire iron
- Large slipjoint/Channellock pliers
- Sockets and ratchet or wrenches
- New set of brake pads-Ensure you know the year, make, and model of the donor car, if applicable.
- Disc Brake Quiet or similar product
- Replacement hardware kit if the calipers came from the junkyard
- Two wheel blocks
Step 1: Apply the Brake Quiet
If you’ve got one, use a drill with an 80-100 grit sanding disc to remove the sharp edges on the pads. This helps to keep them from squeaking. Disc Brake Quiet is a product that helps the brake pads stick to the caliper to keep them from vibrating. This reduces brake system noise. Set the pads friction material down on the box they came in and liberally coat them with the product. If there are any clips or shims, install them and apply more product if required. Let them sit.
Step 2: Remove the Tires
Park on a flat and level surface, put a manual transmission in gear or an automatic in Park and firmly set the parking brake. Block the front and rear of one rear tire. Place the jack under the radiator support of frame crossmembers and raise the jack enough to take a bit of the car’s weight. Using the lug wrench, loosen the lug nuts on both tires a couple turns. Raise the wheels off the ground, remove the lug nuts, and then the wheels. I like to place a piece of cardboard or some shop rags over the sidewall and use it as a stool.
Step 3: Remove the Calipers
I’ve seen Torx bolts, Allen/hex key bolts, and regular hex bolts used to secure the caliper to the caliper support bracket. However, stock is usually either a ½ inch or 9/16 inch standard hex head bolt. If it’s been some time since the calipers have been off or they’re extra rusty, you may need some rust penetrant or lubricant. Using whatever is required remove the two bolts securing the caliper to the bracket. Lift the caliper off the rotor. You may have to rock it a bit to get it out. Hang the caliper from the suspension coil or something so there is no tension on the rubber brake hose. Never suspend the caliper from this hose.
Step 4: Remove the Old Pads and Collapse the Caliper Pistons
This is where it starts to get a bit different when you move between makes, models, and even years of the same model. Pull the outer pad off the caliper and set it aside. Using the outer pad support as leverage, pull the inner pad out of the caliper piston. Turn it over and remove any clips or springs on the back. Install any clips or hardware on the new pads.
Place the friction material side of the inner pad against the caliper piston-the round object protruding from the center of the caliper). Using the large slipjoint pliers (or, if you have the money, disc brake pad spreaders) collapse the piston until it is flush with the body of the caliper.
Fords and Chrysler products from our donor car’s time typically have annoying little clips on the pad wings that need to be transferred to the new pads.
On Camaro and Duster calipers, the brake pads are retained on the calipers by ears on either side of the pads. Tap the outer pad with a wrench or hammer to loosen it. Pads on the other cars should slide off relative easily.
Step 5: Install the New Pads
Now that the caliper piston has been forced back into the caliper bore, it’s time to install the new pads. Pay attention to the old ones. They aren’t interchangeable, the inner pad must go against the piston and the outer pad must go on the outer pad support.
Prior to installing the pads in the GM or Chrysler caliper, tap their wings on the outer pads to bend them down a bit. This will help secure them in the caliper and keep them from vibrating and making noise. Sliding the wings over the tabs on the caliper should take a little bit of effort.
Step 6: Hang the Caliper
Remove the wire or string used to suspend the caliper. Slide the caliper and pads over the rotor. You may need to pull the pads apart a bit. The caliper may require rocking to get it to seat on the caliper support. Install and torque the caliper to support bracket bolts. You should buy and refer to a repair manual (Haynes or Chilton are my favorites) to obtain the proper torque specifications.
Step 7: Repeat on the Other Side
Repeat the steps above on the other side of the car.
Step 8: Hang the Wheels
Grab the wheel and line up the lug holes with the lug studs. Slide the wheel over the studs. Thread the lug nuts onto the studs and tighten them as much as possible with the wheels in the air. Raise the car of the jack stands and pull them out. Lower the jack until the suspension is taking most of the weight of the car. Tighten and torque the lug nuts to the correct specification. Lower the car.