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This is strictly for the rebuild of the piston part of the caliper, which includes replacing the dust boots, seals and clips around the caliper piston.

Please do this at your own risk. By following this guide, you take full responsibility of any problems that may occur. Remember to wear safety glasses when working with compressed air and solvents. Brakes are a very important part of your vehicle, so if you aren't comfortable doing this rebuild, please take it to a professional.

Tools used:
8mm or 10mm socket/ratchet for bleeder screw
Small flat screwdriver
Pick
Small brush
Hone (not a must) & drill
Air compressor with blower attachment
Brake cleaner
Brake fluid
Grease (toyota - lithium soap base glycol grease)

I bought the rebuild kits from Toyota which includes - pink lithium grease, set rings, dust boots, square piston seals, dust boots for the sliding pins, brake line gasket and bleeder cap. I'm only going to show the parts used for the piston below.

FRONT



Disassembly

  • Remove the set rings around the piston boot.
This is located on the outside lip of the dust boot. Use the pick to remove.
  • Lift boot off of piston.
  • Remove brake line bolt and use the air blower in the hole to push the piston out.
Be careful because it will shoot out, so put it against something to block it.
  • Use the pick to remove the piston square seal on the inside of the bore.
  • Remove the bleeder screw
Cleaning

  • Use the brake cleaner and a small brush, and clean the inside of the piston, piston bore and seal grooves.
  • Use the air blower and more brake cleaner to remove all the debris.
  • * May not be needed, but my piston didn't move smoothly down the bore so I used a small hone to smooth it out. Apply some brake fluid to the hone and a little to the piston bore. At slow speed move up and down and keep checking the piston fitment until it moves smoothly. Clean with brake cleaner afterwards because it could of broke dirt loose. *



Assembly



  • Insert the square piston seal and apply grease over it.


  • Apply grease on the outside of the piston.
  • Insert piston. Gently rock the piston back and forth in small movement until it moves past the seal and slides down the bore.
  • Put the boot over the top of the piston then push it down into the groove on piston. Push the outside of the boot down into the groove on the caliper and use the screwdriver to push it flush in the groove.
  • Insert the set ring inside groove around the piston - start at the part away from the bracket and use the screwdriver to push it into the groove once you have it fully seated.


  • Clean the bleeder screw if needed and reinstall.
  • Install brake line bolt - helps keep the piston bore clean until you are ready to install.
You should have a rebuilt front caliper piston now.




REAR



Disassembly

  • Remove the set rings around the piston boot.
This is located on the outside lip of the dust boot. Use the pick to remove.
  • Lift boot off of piston.
  • Remove brake line bolt and use the air blower in the hole to push the piston out.
Be careful because it will shoot out, so put it against something to block it.
  • Use the pick to remove the piston square seal on the inside of the bore.
  • Remove the bleeder screw
Cleaning

  • Use the brake cleaner and a small brush, and clean the inside of the piston, piston bore and seal grooves.
  • Use the air blower and more brake cleaner to remove all the debris.
  • * May not be needed, but my piston didn't move smoothly down the bore so I used a small hone to smooth it out. Apply some brake fluid to the hone and a little to the piston bore. At slow speed move up and down and keep checking the piston fitment until it moves smoothly. Clean with brake cleaner afterwards because it could of broke dirt loose. *



Assembly




  • Insert the square piston seal and apply grease over it.
  • Apply grease on the outside of the piston.
  • Insert piston. Gently rock the piston back and forth in small movement until it moves past the seal and slides down the bore.
  • Put the boot over the top of the piston then push it down into the groove on piston. Push the outside of the boot down on the outside lip on the piston bore - you may need to push the piston down so that the boot doesn't keep slipping off.


  • Put the set ring on the outside of the boot while making sure that the boot stays in position
  • Clean the bleeder screw if needed and reinstall.
  • Install brake line bolt - helps keep the piston bore clean until you are ready to install.
You should have a rebuilt rear caliper piston now.

 

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When I was at the Toyota dealership, they recommended me to change the calippers instead of rebulding them as the problems will come back in a year. They also said for rebuilding calippers one should powder coat the calipper before installing new rubber etc.

But after reading this write-up I sort of want to give it a shot myself. Did you get new rings and the other stuff new?
 

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When I was at the Toyota dealership, they recommended me to change the calippers instead of rebulding them as the problems will come back in a year. They also said for rebuilding calippers one should powder coat the calipper before installing new rubber etc.
Please find a new dealership to work on your car. You don't need to do anything to the caliper for a rebuild except maybe clean it off (I skipped that when I did my rebuild) - you certainly don't need to powdercoat.

You only need to replace a caliper when the caliper or the piston itself is physically damaged/worn to the point that it won't work reliably. Usually all it needs is a good cleaning of the piston from dirt, dried grease etc. I raced my car for 7 years before a caliper failure forced me to rebuild. Took the rebuilt calipers to the track a month later and the brakes performed admirably. If I had the money and had plans for keeping the car longer than 6 months I would've sprung for new calipers, but my brakes see much more abuse than most and a failure on the track has high consequences.

But after reading this write-up I sort of want to give it a shot myself. Did you get new rings and the other stuff new?
If you have a BAP auto parts near you, they sell a rebuild kit (one per caliper) for $8 that has a brand new piston o-ring, dust boot, and set ring. IMO you don't need to replace any other parts unless you suspect a problem with them.

A couple things I'd add to this install guide:

When using the compressed air to fully extend the piston, use a very gentle squeeze of air and don't try to stop the piston with your hand! It can shoot out with a lot of force. Put a rag in between the piston and the caliper to prevent damage to the piston.

Optionally, you can use brake fluid to lubricate the new o-ring and piston for reinstallation. Recommended by another track nut and it worked well for me. If there's too much grease, it may be hard to get the piston back in.

If you need to hone the piston, consider replacing it instead. The piston relies on very tight tolerances to keep a tight seal in the caliper - remove too much material and you could have problems. Make sure the piston is EXACTLY square when reinstalled or it won't compress easily - even if you have it in right, you may not be able to compress with just your hands though.
 

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Discussion Starter #5
When I was at the Toyota dealership, they recommended me to change the calippers instead of rebulding them as the problems will come back in a year. They also said for rebuilding calippers one should powder coat the calipper before installing new rubber etc.

But after reading this write-up I sort of want to give it a shot myself. Did you get new rings and the other stuff new?
Caliper failure comes from ripped boots, then water gets in and rusts around the piston. Once the piston is moving freely again, this shouldn't perform any different than a new caliper. In fact, the reman calipers you buy at part stores, are just rebuilt calipers.

I did powdercoat before installing the new rubber. I tore down the whole caliper to one piece, had it powdercoated, and then put the new rubbers in. The only reason I did this rebuild was because I wanted the caliper powdercoated, and they were used from a junk yard, so it had been sitting for a while.

I barely honed the bore because the piston was sticking. This was mainly to get it true again and remove the corrosion. The piston fit tight in the bore when installing.
 

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Looks like an 30 min job per calipper if done right and if one knows how to do it. It is worth the try. The 100 dollars I save per calipper can be used for other parts. Thank you for nice write up! I will try this. Starting to get trouble with my rear brakes.

Edit: powdercoat to get sexy color! wohoo!
 

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nice write up brandon.

you should add the part numbers of the toyota rebuild kits. Or did you buy your rebuild kit from Napa or something?

I definitely recommend you pull the slider pins and grease with something like silicone grease. It makes a big difference.
 
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