Brake Caliper Rebuild

[Joe Link]

That makes sense. Definitely something I need to be better about.

 

[clx16]

I do what @jonheld does, but usually the spacer is just two new pads still wrapped in plastic. they are usually just thick enough to keep the pistons from popping out. i put them curved side in so the lobs don't let the pads slide over from one side etc. The wood version seems like it is probably more fool proof and a little less hassle.

 

[PZLCruiser]

Back in 2014 I rebuilt my calipers and polished/reused the existing pitted cylinders. Now its 6 years later and im having a sticky caliper. I though it was minimal. Just a reference for others. Get new cylinders.

 

[Malleus]

Also, changing the brake fluid yearly will keep internal corrosion of the entire system in check. Brake fluid is supposed to be water clear.
The darker it is, the more contaminated it is. Since the fluid remains stagnant in the lines, they can corrode from the inside.

If you are on the fence about whether you should change your fluid or not, you can convince yourself it's necessary:
Brake fluid test strips

 

[ERG80]

I’m getting Toyota parts together to completely clean and reseal some calipers. Has anyone found a place to purchase the individual little o-rings that fit between the split calipers?
Edpm rubber Square cut 2mm cs 8mm id 12mm od o-rings
I read that 2mm by 8.5 x 12.5 will also work.
I’m not having much luck and don’t want to buy a seal kit for just those.
Thank you

 

[Malleus]

I’m getting Toyota parts together to completely clean and reseal some calipers. Has anyone found a place to purchase the individual little o-rings that fit between the split calipers?
Edpm rubber Square cut 2mm cs 8mm id 12mm od o-rings
I read that 2mm by 8.5 x 12.5 will also work.
I’m not having much luck and don’t want to buy a seal kit for just those.
Thank you

Someone correct me if I'm wrong, but that's not part of the caliper rebuild. That's why you can't find them.

If my guess about the casting manufacturing process design is correct, the halves exist for the sake of the manufacturer. The o-rings are there because they have to be, to seal an interface which really can't leak once it's assembled. I can't think of a reason to split the castings apart...

EDIT, this just in ...

 

[jonheld]

Someone correct me if I'm wrong, but that's not part of the caliper rebuild. That's why you can't find them. I can't think of a reason to split the castings apart...

No need to split the housings apart IMO. Frankly if I needed to go that far for whatever reason I would opt for new calipers.

 

[ERG80]

@jonheld @Malleus thank you both for the replies.
Malleus, you’re correct that those orings aren’t part of the Toyota kit but they are included in some aftermarket kits.
The used calipers I have for a rebuild appear to be in excellent condition but are dirty and greasy. Some of the dirty grease found its way Into Brake line hole while in shipping so I thought it would be best to split them for the most thorough cleaning.
I’ve read about recommendations not to split the calipers but The process to split them seems so easy I wanted the piece of mind of cleaning them out.

 

[jonheld]

The used calipers I have for a rebuild appear to be in excellent condition but are dirty and greasy. Some of the dirty grease found its way Into Brake line hole while in shipping so I thought it would be best to split them for the most thorough cleaning.

A bit of brake cleaner and compressed air makes short work of that.

 

[Gary S]

You can also use two screw drivers to very gently work the piston out with many short pushes back and forth side to side. You must use extreme caution so you don’t mar the sides of the piston or it will develop a leak and ruin the sealing ring in the future. Also never pry on one side only as the piston has a very precise fit and can get wedged in its cylinder and be very difficult if not impossible to get out without damage, use tiny increments side to side. Using air is the preferred method. As you remove the pistons you should place them in same order that they came out of the caliper or number them along with the caliper so they can be re-installed into the same cylinder. Once out remove the sealing rings from of each cylinder with a small angled pick, again being careful not to mar the cylinder walls. Now clean all cylinders and pistons with a clean paper towel and brake cleaner. You may need to use a pick or very small flat screw driver to get all gunk out of the piston and cylinder channels crevices. There may be some deposit that is difficult to get off the piston sides, if so you can use a razor blade and “shave” the piston side. Never use the tip of the blade and be very careful not to damage the surface, think like a razor shaving hairs with no nicks.

1. This is the two screwdriver method but be VERY careful if you do this, it really is easy to mess up the piston.
2. Using a 90* pick to remove the piston ring.
3. The removed pistons on the bench, the front left is a before and the front right is an after cleaning. I just used a clean rag, brakekleen, and a fresh razor blade.
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While your on disc brake rebuild, may be old news, but new to me, I finished brake rebuild on my 79 FJ40, everything went well but now have fluid leak from bottom of caliper, separated the caliper and discovered one of the small flat surfaced o rings is bad, can’t find anywhere, any ideas? Will a standard round oring work?
Thanks, Hondo

 

[Antipodes4WD]

I finally decided to tackle my front birfield repack, front and rear wheel bearings, etc and my rotors already had a pretty good warp so I finally got to replace them as well since I was in there. Mars recently did an excellent write up on caliper replacement with reconditioned units but I couldnt find anything on rebuilding the brake calipers so I thought I would write it up in case anyone could use a good reference. It seems intimidating to many people but I think it is something any 1 - 2 banana mechanic could tackle. The benefit is that the two kits together cost less than one rebuilt caliper and each kit rebuilds both respective calipers front or rear. A little extra time spent to save a good bit of money. Tools required: Set of picks for getting out rings and seals etc. 17 & 14 mm socket and ratchet 10mm brake line wrench 6 mm allen wrench 1 Small and 2 medium flat blade screwdrivers Air compressor with blow nozzle FSM Brake bleeder - available at Harbor Freight for $20 Parts: 04479-60030 Rear Cylinder Kit 04479-60020 Front Cylinder Kit 3-4 cans of brake cleaner Roll of paper towels Extra non moly grease, I used Redline synthetic 2 small or 1 large bottle of brake fluid This is the obvious time to do a brake fluid flush, which is often overlooked (see FAQ), as well. I first used a 60cc syringe (a turkey baster will do) to drain the reservoir. This is not necessary but it does make for a little less mess and fewer drains of the brake bleeder. I then went to each caliper and removed the two mounting bolts and used the brake bleeder to suction all the brake fluid I could by inverting each caliper independently so the bleeder valve (normally the highest point on the caliper) was the lowest. This gets the most fluid out so less will come out when you remove the pistons. Brake fluid is very caustic and damages paint so use caution. Pic 1 Front caliper mounting bolts Pic 2 Rear caliper mounting bolts closest to shock body Pic 3 Two rebuild kits from cdan, It has been said many times before but thanks for the help cdan.
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Hello Slomo, great and detailed post! I hope you still remember how the calipers look inside. I am going with a simple fluid replacement Do I remove and keep the calipers upside-down when replacing brake fluid. - https://forum.ih8mud.com/threads/do-i-remove-and-keep-the-calipers-upside-down-when-replacing-brake-fluid.1362673/ but my concern is that the caliper break cylinders are not seeing the new fluid the way fluid replacement is advocated on Youtube. What is your opinion on that?

 

[clx16]

That post is from 2007 and Slomo hasn't been on the forum this year. However if you compress the cylinders in the caliper, you will be pushing out all of the fluid in the caliper. So no need to flip them around etc.

 

[TheRareElement]

Done Rear.......
Excellent technical details by SloMo & others' valuable input.
Thanks to everyone..

My 2 cents worth :
Rear Brakes :

* "Assumption is the Mother of All F#@k-Ups". In a moment of recklessness & in a hurry to do it, I assumed the the front & rear piston seals are same size and that Toyota staderdized them, I was very wrong, they are not, I have a front seal kit missing one seal. The installation seemed fine, closed up everything, went to the rear passenger side to work on the opposite caliper and found the left side one leaking after I closed it up. This is what happened when I forced the piston into the cylinder with the wrong piston seal

Fitting the boot after the seal was a PITA, but then found this post & followed SloMo's method & everything was smooth.

* I opted to use a 2mm rubber strip (4x10cm) with a flat head vice grip to seal the brake tube, found it easier to fold and seal the tube quickly to avoid too much mess.

* Make sure bleed nipples are clean & air flows through them easily. Mine we all rusted and clogged, heated them up lightly with a blow torch then dipped in water a few time, then some brake cleaner spray, wiggled a small copper wire through the orfices and bingo, nice & clean.

To be continued due to 5 pic limit.......

 

[TheRareElement]

* Take your time cleaning the cylinder, piston, pins & all parts. I used a 1500 grit sandpaper to remove discloration & whatever gunk was in the cylinder & on pistons.
Also check on the brake fluid channel (hole) at bottom of caliper to make sure it is clear, brake cleaner & compressed air.

All set & ready for install back on disc. Make sure rubber insert of upper pin is set in properly.

To Be Continued................

 

[TheRareElement]

Front Brakes.....
These take more & more cleaning.
* I used @KLF's method to push pistons after removing brake pads but caliper still in place, it works perfect, Thanks @KLF.

* I used rubber strip method to seal brake line after removing it from caliper.
At this point check the brake lines for any problems, mine was superficially cut after +675,000 Km. A new pair are on the way in the post.

* I opted to work on the caliper without splitting it due to the drama of the O-rings in there. Didn;'t have a problem taking the pistons out & replacing old piston seals. Cleaning the cylinders took a bit of effort due to the geometry of the caliper and the difficulty of getting your fingers in there with a 1500 grit sandpaper to clean properly.

* Almost done after changing seals & boot and ready to install of brake disc.

* WAIT, DID YOU CHECK THE BRAKE FLUID CHANNELS INSIDE THE CALIPER ?
I took everything apart again (removed metal ring, boot, piston & piston seal and went ahead checking flow in the caliper and good I did that as some channels to some pistons was clogged. Brake brake cleaner and easy on the compressed air, make sure the brake fluid channels between pistons on same side are clear and channels between opposite sides of caliper are clear and that air flows well through the whole caliper up to the bleed nipple (hope I explained this clearly).

* Now all installed and ready to go for a test drive.....

My babe brakes beautifully now
One last thing, I'll make sure to change my brake fluid once a year, better keep those brake parts free from corrosion.

That's all.....
Big thanks @Slomo for his excellent write up and all those who contributed, what a source of genuine collective intelligence.
Working on you brake system is not that difficult if you have basic mechanical skills & have some simple tools, expecially that your life could depend on the integrity of the work.
Take care guys

 

[jonheld]

An easier way to seal the brake lines after removal for $0.25. DON'T USE THE FLAT WASHERS.
Personally, I don't reuse brake parts when rebuilding calipers. All new OEM parts all the time.
Not the cheapest option, but I never cut corners on brakes.