HELP!!! pulling my hair out on brake caliper rebuild

Ok here is my story and I am hoping somebody has an answer for me. I had my brakes fail due to my flexible brake line rubbing against the frame and wearing a hole in the flexible line. i Replaced the flexible lines on both sides and decided since I was getting close to needing to replace my pads that I would just rebuild my calipers and repaint them while I was working on them. because one of the bleeder screws broke off in the caliper.

So I removed the calipers, pulled them apart, sanded them down and repainted the calipers and had the rotors resurfaced while I was waiting on my caliper rebuild kit to arrive. Got my rebuild kit finally and when I went to replace the O'ring that seals the brake fluid channel between the 2 pieces of the caliper I noticed there was no replacement Oring in the rebuild kit for that.

IU could not find a part number for it anywhere so I called the dealer. He looked it up and told me that toyota does not stock that Oring and it is unavailable because they do not recommend separating the halves of the caliper due to potential resealing problems.
The damn thing is not available. He even emailed me the schematic of the caliper with the notation on the schematic stating as such.

unfortunately I removed everything from the calipers and discarded the old Orings before the parts kit arrived as it never crossed my mind that a replacement would not be included in the kit.
You will see on the attached file that the notation on the lower left of the picture confirms this. So I do not know what to do now. Any help would be appreciated at this point with my truck on jackstands and out of commission in the driveway!!!

Just an FYI the original Oring is square cut (flat) and not a normal type Oring

 

Hardware places sell O rings.

caliper separation is not recommended. Rebuilt kit involves replacing the piston seals and dust boots.

 

yes well I guess I will know next time. I watched several YouTube vids rebuilding and repainting calipers that separated the calipers to be able to clean and repaint thoroughly. I guess I will just need to buy another used caliper on ebay and start over.
When you are anal retentive about everything and not cutting corners it will bite you in the arse sometimes.

 

In the navy we called those wall seals... the true name is lathe cut rings... They give a better higher pressure seal than standard o-rings.

See here: https://www.alleghenyyork.com/wps/portal/c/blog?p=what-is-a-square-cut-o-ring-and-how-are-they-used

 

an aftermarket seal kit may have that o ring.

or you can try putting the caliper back together, re use it, and see what happens.

wouldn’t be a bad idea to apply some seal grease to it.

 

You're better off buying remanufactured calipers than trying to get the bleeder screw out and the pistons removed for fresh seals. Royal pain in the arse to rebuild.

 

The best part about going with reman calipers at this stage of the thread is that you can give them your trashed caliper as a core and they probably won't bat an eyelash about the O ring not being there. Wash your hands of it and lesson learned for next time.

 

Sorry you're in that situation.
That washer should have come with the caliper rebuild kit. (From Rock Auto: CARLSON 15289 Disc Brake Caliper Repair Kit Info
Front; 4WD)

I just found one in my spare parts bin. I thought I had saved 2.
Strange as yesterday I found one in the area of my back yard where I rebuilt 4 Tacoma calipers. I picked it up and flicked over the fence.
I had a hard time finding the torque value for the caliper bolts.
Too bad you threw the old washers away as they really don't degrade.

 

AutoZone sells refurbished calipers. I think it was $70 for one, but that was last year. Not sure what the price is now. At $70 for a replacement, i didn't even bother trying to rebuild mine...

 

That statement needs some qualification. Many, remanufactured calipers are very poorly built. I've seen way too many cheap, remanufactured calipers (and other parts) fail in unbelievably short order. Beware!

 

rebuilding a factory caliper is usually better than most aftermarket.

I don’t know what kind of pressures the braking system sees.
But one theoretically could replace that seal, observe it for leaks connecting to a pressure bleeder.

then go for a road test and recheck. Potentially hard stopping later on assuming the rotors are ready for that (new rotors are not for the first 100-200 miles).

potentially spraying talcum powder spray on the area to aid in leak finding, to inspect if there are any.

some caliper halves may be flat. Old Audi calipers they say not to take apart: the reason is due to microserrated bolts that have sharp teeth meant to bite in one time. I accidentally took one apart before. Don’t recall seeing an O ring in addition to that. (b7 a4 2.0t 321mm). Put it back together, tightened it, ran it without issue.

 

thanks for the Rock auto link. I bought a used caliper on ebay before I saw that just so I could get things moving.
I did have one I took out of an old caliper but was still short one.
This thing has become way too complicated for what it should have been.

Where did you find the torque on the caliper bolts? I can't seem to locate it.

 

could be an opportunity to do 4runner BBK.

 

Cardone and Nugeon are quality.

 

What the heck!? No, that’s a terrible idea. It will leak without that o-ring, and then he’d have to start all over new. I rebuilt my calipers last year and also separated the halves to properly clean and paint. Pretty sure my rebuild kit came with o-rings or maybe I got away with re-using the old ones… no leaks either way.

OP, look up the oring store online. Just need measurements.

 

Wow, you must live where they don't use road salt. They look awesome!

 

re-use

honestly, those bolts don't look microserrated
typically it's Germans and their partners doing crazy such things
doesn't look like a Cracked-style mating interface either. Which, if it was, it would still match.

Question is what condition is the old seal in. It's been exposed to years of heat and hydroscopic DOT4.

 

Brake fluid is hygroscopic not hydroscopic. Just clarifying not criticizing, it's easy to mix up the terms.

 

Thanks. But that was after painting. Worst part was wire wheeling and cleaning beforehand. Pure elbow grease. Yeah, no road salt here on the Olympic Peninsula, but we got salty air

OP says he tossed the old seals. Your statement which I initially quoted suggested to just put them back together without and see what happens. I just wanted to relieve the suspense; leaks! That’s what would have happened.

And technically it’s DOT3, at least from the factory, but DOT4 would work just as well, as long as it’s not DOT5.

I’m not worried about the calipers separating. I used some loctite left over from gun barrels (620 I think?) so it can take the heat. Dykem on the heads for extra insurance, so I’d notice right away every time I look under there.

 

what is seal grease?