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Picture of How to Rebuild a Brake Caliper (WITHOUT Removing It From You Car!)

Brake calipers are located in a very dirty area of your car and are subjected to years of abuse at the hands of road dirt, water and salt (and as a result of your 'sporty' driving technique!).

Eventually the piston can corrode and the brake caliper will seize (aka 'freeze') and when you release the brake the brake fails to release. If this happens you may hear 'squeeling', smell overheating of the brake components and the entire wheel may get very hot.

My 1999 Ford Focus has lived its life in the wet and windy North West of England. The fact that this 18 year old car still drives like a dream despite this (and despite the fact I bought it years ago for only $800 and despite my sporty driving technique...) is nothing short of a miracle! However, one of the brake calipers did seize recently so I had to fix it - hence this Instructable.

Often the whole brake caliper assembly is replaced when this happens but that is a real shame: They are very simple things, and for about 20 USD you can buy a brake caliper repair kit (which can include a brand new piston) and with an hour or so of work, your caliper will be as good as new!

If you're in a hurry to get your car back on the road, like I was, then you don't even need to remove the brake caliper from your car: you can refurbish it with the brake line still attached.

(Yes, there will be people who say "don't clamp your brake line" but I have worked with hydraulics for many years and see no problem with this. I have never seen an actual case of a brake line being damaged by clamping - I have only ever hear anecdotal stories and warnings. If you take your car to a garage, most of them will clamp the brake line and you will never even know they did it...)

If you have decent internet access then the video above shows you the whole process. If you prefer to read the Instructableubblyabubblyubblyabubble steps instead, then please feel free to do so.

Tools / materials required to complete this job:

  • Jack
  • Axle stands
  • Drip tray
  • Socket set
  • Screwdrivers
  • Hex key set (aka allen keys)
  • Brake caliper repair kit for your caliper
  • Brake fluid

Step 1: Jack Up the Car, Support on Axle Stands and Remove the Wheel

Picture of Jack Up the Car, Support on Axle Stands and Remove the Wheel

Crack the wheel nuts, then jack up the car and support on axle stands. This needs to be done safely, but we won't cover the procedure for this here, other than to say never work under a car supported only on a jack!

Remove the wheel to gain access to the brake caliper. Feel free to sit on the wheel whilst you do the rest of the job. :-)

wrenchtoo24 days ago
I hate to be negative, and there are plenty of things I do with cars outside the norm but...I have worked with people (professionals - you're right some do it as you discribed) that clamped the hose, I have also seen firsthand problems that can caused by this practice. In short the hose collapses on the inside and won't fully release - symptoms are burning smell, components running hot, premature wear, brake(s) locking particularly when hot. To each their own, but everyone should be aware of the possible downside and that it can and does happen.
gm2801 year ago

I recently rebuilt all four brake calibers on an older 96 Jeep Grand Cherokee. But I removed them from the vehicle, sandblasted them to clean bare metal, primed and repainted them. I replaced the pistons and seals and dust boots as well. And they looked and performed like new afterwards.

Random Chris (author)  gm2801 year ago

Hi there, it sounds like you did a very thorough job and those calipers will be like new from the factory. I needed my car back on the road ASAP (Not being able to drive 'drives' me insane!) and I wanted to fix the caliper really quickly. It took about an hour, sost just $20 for the repair kit, and the caliper has worked perfectly ever since. My car is 18 years old now so I'll probably look at changing it in a few years... :-)

Random Chris, please don't take my comment wrong. There is nothing wrong with how you did your calibers. I was only stating that I just recently rebuild the entire brake system by thoroughly clean all the rust and gunk off first and then rebuild them back to like new. And since there was no pitting in the bores, then new phenolic pistons and seals worked perfectly. Nice having sound brake now.
Random Chris (author)  gm2801 year ago

Hey there - not at all, I appreciate your comment and it's great to know that other people out there are enjoying looking after their own cars, rather than taking them to the mechanic to fix every problem. :-)