Caliper Rebuild

[89Laredo]

Keep in mind that I am NOT an expert and this is my first rebuild, I may have done something different/wrong.
I am not suggesting you follow this as a definitive guide to caliper rebuilding, it is just an example of what you can expect on a rebuild and how I did mine.
I am not responsible if you kill yourself or someone else.
I was also taking most of these pics one handed and covered in brake fluid/grease, I see a lot of them didn't turn out too good.

1:
Buy rebuild kit

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2:
Remove caliper, drain fluid, put in vice.

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3:
Use a c clamp or something to hold one piston in. Use compressed air to force other piston out. Stuff some rags in there, they pop out with a lot of force.

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http://youtu.be/OWRBeqWqKAw

4:
Slightly reinsert the piston you just popped out, just enough to make a seal. Hold in with c clamp, pop out other piston.
You may have one that is stuck. Spray penetrating oil into the caliper and let the piston soak in it. You may also have to force the piston IN with the vice. Be patient, it should pop out easily after a while.

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5:
Clean up the caliper body. Hone/emery cloth the bores. Clean with brake cleaner, dry with compressed air.

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6:
Lube your seals and insert into grooves.
I used silicone grease, this may be wrong, you can just use brake fluid.

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7:
Clean piston. Emery cloth/scotch brite.

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8:
Lube sealing surface of one dust boot and insert into caliper. Didn't get a good pic of this.

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9:
The trickiest part of this and I didn't get a pic. Insert one piston into caliper to create a seal like you did earlier, hold in with c clamp. Hold other piston against dust boot and apply compressed air through the banjo bolt hole. The dust boot should blow up like a balloon and go over the piston easily. It's tricky but doable.
As you push the piston into the caliper the dust boot will seat into it's groove.

10:
Use c clamp to push the piston in. Then hold it there and repeat step 9 with the second piston, push second piston in.

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11:
Clean up slides on wire wheel. You have successfully rebuilt a brake caliper.

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[dunk]

I'm debating on buying rebuilt vs rebuilding mine. Buying reman is cheaper unless I need to replace pistons... But flipside is do the cheapie Mexico rebuilders replace pistons that I would deem unacceptable? They probably accept pitted pistons that I wouldn't consider reusing so I may end up rebuilding mine.

Also I'd add a step after your first degreasing... Blast the rust off, clean all the grit out, paint with caliper paint. Maybe I'm OCD but I always do that sort of thing to keep things from getting crusty.

 

[89Laredo]

I think I paid 6 bucks for two rebuild kits. Its not a hard job, the hardest part is getting the boot over the piston, wish I could get a video of that.
But imo if you tear the caliper apart and find two nasty looking pistons you may be better off just buying a reman. From what Ive seen the pistons are almost the same price as a reman caliper.

Cleaning and painting is not a bad idea but I always think of things as a matter of time/work involved. Yes, painting will make them look pretty but is there really any other advantage? Not that I can see, The important parts that would "become crusty" (slides, piston, "key" and spring, bolt threads) wouldnt be painted anyway and should be covered in grease on reinstall if you know what you are doing.
A sandblaster is on my list of things to get eventually though. At that point cleaning and painting would not require much more time and I would definitely do it.

BTW this is not my shop, I just use it. The mess isnt mine.

 

[dunk]

You got it, the turning point for me in thoroughly cleaning and painting everything was when I got a sand blaster. Just too easy not to. Wire wheeling a complex shape didn't happen often. But yes, pistons+rebuild kit it's a crapshoot whether it's a little over or under cost or a reman. I'd love to see the pistons on a few "new" reman units though, whether they're pitted or deeply scratched. Gotta weigh time vs doing it myself and knowing it's done right to last. Mine is a forever truck, so every corner I cut or penny I pinch now means more time and money later so I prefer to do it 100%. When I get into anything.

 

[riotwarrior]

Great job, ya those sucka's pop out something fierce and ya a rag or block of wood or or or is good idea or lose an eye or get a black one

Should see this moving to TECH section soon I bet!

NICE JOB!

Thanks for sharing the info!

 

[icanfixall]

Two things I would do differently. First off I would add a block of wood between the caliper body and the piston. That cup can hurt you badly when they blow out like yours did. Secondly I would check into a grease that I was sure did not react with the seals. Or just use the brake fluid as a seal lube. Most motor oils react badly with the rubber parts in brake systems. Otherwise this is a great idea. I have rebuilt the calipers on my 79 chevy truck once. As you said those dirt boots were tuff to install correctly. The brakes were the Bendix type commonly found on early trucks. We just had a long post about a member replacing the bendix calipers with the other types. That was a harrowing experience for plenty here and I'm happy it came to a safe conclusion.

 

[89Laredo]

I did the piston removal without a rag to show what happens.
Silglyde is fine for rubber, same stuff I was told to use on oil cooler.

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[89Laredo]

And a blooper. Thought my look of "***, that wasn't supposed to happen..." was kinda funny.
Make sure the clamp is tight.
http://youtu.be/aHi8eHx9JQU

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[mblaney]

I just rebuilt mine. To remove the pistons I put a stack of three brake pads on the caliper to limit the travel of them when using compressed air. Then remove one and blow again*. Much safer than having them pop out. I bought the same rebuild kit that you have pictured.

*Wear safety glasses. When you remove your air line the caliper will vent and blow brake fluid mist in your eyes.