Rick's Free Auto Repair Advice

Rebuild a brake caliper

Should you rebuild a brake caliper?

Some rebuilt brake calipers are so cheap that it doesn’t make sense to rebuild your old ones. Then again, if you’re the type that likes to dig deep into everything and rebuild things, here’s what you need to know about whether you should even take on this task.

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

What’s the condition of the bracket?

Do the slide pins go into a bore on the bracket and are the

seized brake caliper

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

bores in good condition or corroded? If the bores are severely corroded, you’ll need to clean them with a small wire brush to remove the corrosion and then hone them. It’s doable, but the cost of the bore honing tool is something to consider.

Are the threads in good condition? It doesn’t make a lot of sense to buy a helicoil kit or even a thread chaser to restore the threads in a bracket when you can buy a rebuilt bracket for less.

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.

What’s the condition of the caliper pistons?

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.

Can you remove the bleeder screws?

If the bleeder screws are rusted in place and you’ve tried everything to remove them, give it up and buy a rebuilt caliper.

What you will need to rebuild a brake caliper

Seals, dust boot, pin boots, slide pins and brake assembly lube for brake caliper rebuild

parts needed for caliper rebuild

New caliper pistons

old versus new caliper pistons
How to rebuild a brake caliper

Place a block of wood in the caliper and cover 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.
• Reassmble the caliper and install on vehicle.

©, 2023 Rick Muscoplat

Posted on by Rick Muscoplat

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