Should you rebuild a brake caliper?

DIY Brake Caliper Rebuild: Tackle It Yourself or Leave It to the Pros?

Rebuilding a brake caliper can be a moderately challenging task, but it’s doable for those with some mechanical experience and the right tools. The process involves disassembling the caliper, cleaning all the components, replacing seals and possibly the caliper piston, and reassembling it with care. The difficulty largely depends on the type of caliper and the condition it’s in.

Things to check before you can even think about rebuilding a brake caliper

What’s the condition of the brake caliper components?

• Check the caliper slide pins— Do the caliper slide pins move easily into and out of the bores on the bracket? If not, rusted caliper pins and corroded bores and make the job a lot harder

If the caliper slide pin bores are severely corroded or the slide pins are seized, purchase a replacement caliper bracket. That’s about half the cost of a new caliper

• Check the caliper bracket threads— If the threads are in good condition, it’ll be easy to reinstall on your car. If not, you might have to drill and retap, turning this into a huge job that’s not worth it.
• Can you remove the bleeder screws?— Too many DIYers put this off until the end of the rebuild only to discover that the bleeder screws are rusted solid and have to be drilled out. Again, that makes this a much bigger job.
• What’s the condition of the caliper pistons?— If there’s corrosion on the pistons, that’s a deal-breaker. The corrosion will damage the new square-cut O-rings. If you have to buy new pistons, it would probably be cheaper to buy a professionally rebuilt caliper.

If you have phenolic pistons, look for any cracks or chips. If you find any, they must be replaced. For metal pistons, corrosion is a deal breaker; they must be replaced.

• What’s the condition of the piston bore?— To determine this, you’ll have to remove the dust boot, piston and square cut O-ring. The bore should be clean, and the land where the O-ring sits must be completely corrosion-free. If there’s corrosion on the O-ring land, it’ll leak. In that case, the caliper is not rebuildable.

Now make the decision whether to rebuild the caliper yourself

If you don’t need new pistons and the caliper slide pins and bracket are in good condition, you can save money by rebuilding your calipers yourself. However, if the pistons are corroded, the bleeder screws are stuck, or the slide pins don’t slide, you’ll most likely save money by buying a rebuilt caliper.

The tools and supplies you’ll need to rebuild a brake caliper

1) Caliper rebuild kit: New square O-ring seal, new dust boot, C-clip
2) New caliper slide pins:
3) New caliper slide pin boot kit: New accordion boots and rubber pin sleeves
4) Brake assembly lube: Trust me on this. It’s not easy to get the piston back into the bore without assembly lube.
5) Dust boot installer tool

How to rebuild a brake caliper

Place a block of wood in the caliper and cover it with a rag while you apply compressed air to the brake hose port. Then, blow the piston out of the bore.

• Remove the piston, dust boot, and square-cut O-ring.
• Clean the bore and dust boot sealing area
• Lubricate the new square cut O-ring with brake assembly lube and install in the bore (lube it makes the installation go much easier).
• Place the dust boot onto the new piston. Apply assembly lube to the base of the piston. Square up the piston with the O-ring and rotate the piston as you push it past the new O-ring.
• Fully seat the piston.
• Install the dust boot.
• Install new slide pin boots.
• Install new rubber vibration dampener seals on the slide pins.
• Lubricate the slide pins with high-temperature synthetic brake grease.
• Clean rust off the abutment areas on the bracket and apply a light film of brake grease to slow down future rust formation.• Reassemble the caliper and install it on the vehicle.

©, 2023 Rick Muscoplat