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Hagerty Employee

3 tips for rebuilding your brake calipers | Hagerty Media

Hydraulic brake systems can be intimidating, no bones about it. From where I sit, that intimidation factor is a good thing because it keeps people cautious about working on the most important feature of their car. If the brakes don't work, you have a paperweight-and a dangerous one, at that.

That was short. Must have almost missed the deadline.
New Driver

I agree...sorry not to be Neg, but that was pretty pointless. watch your little digits, have clean parts, and oil it. I didn't see any "video" to watch only 3 pics.?
New Driver

You missed a 7:45 video after the second paragraph? Possibly time to upgrade your browser from Netscape to, I don't know, ...... anything else!

I don't see it either, and I'm using "the latest version" of Firefox.
Intermediate Driver

I am seeing it just fine using Microsoft Edge. This despite being on a work computer that has restrictions on video. I do suspect this is in fact a browser issue. It might be due to missing plugins, an enabled blocker, etc, but is definitely the browser and not the site.
New Driver

Do not use DOT 5 silicone fluid. Corvette Stainless Steel Brakes Inc. specifically states that DOT 5 Silicone Fluid voids all warranties. I was told that the EPA forced a change in the formulation a few years ago and that it now attacks and dissolves all seals, including silicone seals. Beware.
Intermediate Driver

Interesting. Thanks, new info. My street rodded '35 Ford uses silicone fluid, same fluid remains after 20 or so years. However, the plastic container the initial fluid came in has developed a crack about at the top of the remaining fluid. Container aged out? The DOT 3 fluid in our daily drivers gets replaced every several years to clear out moisture, etc.
Intermediate Driver

DOT 5 is OK if you are starting out with a completely disassembled system that is free of glycol based (DOT 3, 4 and 5.1) fluids. It does not absorb water and any water in the system, including any in any glycol fluid, will puddle and corrode. For use in any system that is not totally clean and dry, use DOT 3, 4 or 5.1, depending on the severity of use and temperature requirements.
Pit Crew

If the piston doesn’t come out easily, connect a zero to the caliper and use a grease gun to dislodge it. The advantage is that you will not have a heavy high speed middle flying across the garage. The did advantage is that you will have to carefully clean and degrease the caliper, but you were going to do that anyway.
Intermediate Driver

VERY good way of doing it! I work on old motorcycles and have been using this trick for years.
Intermediate Driver

Also, on some calipers you can loosen the end of the grease gun fitting and it will go on the bleeder. Makes it easy, just loosen the bleeder and pump. I also put a short bolt and copper washer in place of the brake line to seal the caliper.
Pit Crew

A couple of observations: If one part of the brake system between the piston and the master cylinder is under 1000 psi, all parts including the fittings and the brake line are also seeing 1000 psi.

In a dual piston system, if one piston pops out and the other remains in place, put the popped out piston partway back into its bore and place a piece of wood or a clamp between the piston and the opposite caliper face and continue to apply air pressure to get the other piston to pop free. Since air is compressible, on really stubborn pistons you may need to use grease by adapting a grease fitting to your hand grease pump and applying the non-compressible grease. Clean the grease contaminated cylinder thoroughly before proceeding.

On aluminum cylinders, avoid the use of steel wool, and use scotch brite pads to avoid embedding steel filings into the aluminum which will rust and expand and leave sharp particles which can tear or damage the seals. Inspect carefully for corrosion especially in areas where the seals for the pistons ride on the bores. Orient the seals in their correct locations facing the correct way.

Cleanliness is next to Godliness in Brake rebuilds... so act accordingly.

You beat me to the steel wool part. Useful but nasty stuff as it always fragments.

Also, scrubbing with a toothbrush and brake cleaner without eye protection can become very unpleasant. And I clean parts outdoors to minimize breathing cleaner fumes.
Pit Crew

thank you for posting that how to,,,with that said a lot of calipers most in fact do not come apart that easy especially when they have been sitting for a period of time....and there is always also the stuck bleeder nipple doing one that address' these problems when it comes to a rebuild and what is needed when you encounter those problems would also be most helpfull...

Having a bit of experience with 4 piston Bendix calipers on my 1970 AMX, I discovered sometimes the only proper rebuild is to install stainless sleeves when the bore becomes too pitted to hone out. This will require machining out the bore & pressing in the sleeves so it's not a cheap fix but it is a long lasting fix. Mid 60's Corvettes experienced the same problems too. I would have liked to seen more in this article about rear calipers with parking brake shoes inside & the disassembly process which can be cumbersome to say the least.
Pit Crew

Remember, use silicone grease whenever contact with rubber will happen (eg. caliper pins). Petroleum based grease will swell the rubber. Same thing will happen if any petroleum-based fluid other than brake fluid is poured into the master cylinder reservoir. I've worked on cars where someone used power steering fluid in a pinch, and it caused brake failure due to destroyed rubber in the brake hoses, master and wheel cylinders, proportioning valve, and ABS parts on newer vehicles. Very expensive learning curve.

We use nickel based anti-seize on the external parts that slide. It seems to last longer than anything else. Also, we flush the brake lines with brake cleaner and compressed air after they have been disconnected from the master and brake cylinders/calipers/combination valve. Patience and attention to detail is key here!
Intermediate Driver

Most of the time, if they are bad enough to leak or are frozen up, they are too bad to be able to repair at home. One comment said that in many cases the bore will have to be sleeved. That is true. You can't hone out the pits so they won't leak. Unless the part is rare, get a replacement. It's not worth the time and aggravation. If it is rare, you will have to send it out to be rebuilt. Brake systems are not the place to go cheap. Years ago I would get the wheel cylinder kits for drum brakes and hone them out. They worked, but for how long? Calipers are harder to do and more critical due to the heat involved in normal operation.
Intermediate Driver

I "bag" the assembly into a large sock before popping out the pistons. This allows the air to escape and keeps the parts from flying. Don't forget your safety googles.
Advanced Driver

I imagine there are some applications where the time/cost of overhaul is justified, but pretty much every application that I have been involved with, the right answer is go to the parts store and get a new one
I just googled that particular application and found examples of new calipers from $23.95 to $39.98. The overhaul kit is 20 bucks without pistons
Not feeling this one, sorry

I'll invite debate with this comment: I maintain that the brakes are the second most important system after steering.

I'd rather be able to stop than have the choice of what I am going to hit.

funny, the pic show a bike caliper. The vid shows piston removal (we skip that in cars usually) and he sez "cars" in the vid while wrkin on a bike caliper. Still good pointers...
Pit Crew

Kyle - would love to see you wearing safety glasses when using pressurized air, spraying brake cleaner, using steel wool, and basically anything that remotely generates the opportunity to get something in your eyes. Also, instead of steel wool, bronze wool is also available and does not risk leaving any little bits that corrode. Of course, cleanliness is right next to Godliness when assembling brakes no matter what you use. Great video and thanks.