Kelsey hayes o-rings

[Kendog 170]

I seem to have bad luck cutting the o-ring when reassembling the KH 4 piston calipers. It sucks to have to buy a complete kit so I've found what looks like the right size o-ring but not a suitable material for brake fluid. I know Natural Rubber or Silicne will work as well as some other just can't find them. Here's what I believe they are size wise but could be wrong. I wanna buy a 100 pack if I can . Anyone try to do this ?
McMaster-Carr

 

[Oldmanmopar]

They are not o rings they are a square type style seal. Don't use o rings

 

[AJ/FormS]

Don't use o rings

Agreed,
the O-rings while sealing, will not provide seal-retraction, and the pads will continue to drag on the discs after every brake application, unless you provide knock-back, like I do with a loose wheel-bearing adjustment.
But that is not the end of it; as you know, the groove for the square-section OEM seals is.... um square-bottomed. It will quickly become "gunked up" with rust, driving the seal into the piston, and providing a leak-path to the brake fluid.
To prevent seal cuting, use a silicone O-ring lubricating grease, and make sure the sq-bottom grooves are rust-free.
One more thing; it is said that,from the factory, those KH pistons were prone to sticking, and they blamed the hydroscopic Dot-3 for that. IDK if that is true, but as a preventive measure, I used the silicone stuff, Dot-5, I think it was, and have not had any stiction since 1999, nor have I ever changed or flushed the fluid.

 

[hemi71x]

I seem to have bad luck cutting the o-ring when reassembling the KH 4 piston calipers. It sucks to have to buy a complete kit so I've found what looks like the right size o-ring but not a suitable material for brake fluid. I know Natural Rubber or Silicne will work as well as some other just can't find them. Here's what I believe they are size wise but could be wrong. I wanna buy a 100 pack if I can . Anyone try to do this ?
McMaster-Carr

I have no idea why your trying to use "O" rings for piston caliper seals on the Kelsey Hayes disc brakes, but if you are, you're doing it all wrong.
Caliper kits are easily available from Raybestos, Centric, Rock Auto, vendors.

If your installing pistons in the calipers, and are ruining the seals, your not doing it correctly, not lubing up the seal, bore, piston, with slippery lube or you need to learn a different technique in piston installation.
They are not hard to do, but if your a beginner it may be a learning experience on your part.

 

[Kendog 170]

They are not hard to do, but if your a beginner it may be a learning experience on your part.

I did rebuild the Calipers that are on there now and I'm remembering how I cut 2 seals. Probably rookie mistake on my part as you said. I am now getting ready to rebuild a spare set to have on hand. I just thought $15 for a pack of 100 why not? These are flat edge seals just like what came out of it not round o-rings. Just trying to get the proper material. I know you use to rebuild them as well. I just like to have extra stock around in case I want to pop one apart to clean up or something.

 

[Dana67Dart]

So let's say you use a not specifically designed for the application seal. Now let's say you are driving and the brakes fail. Now let's say you kill someone.

Lawyers love that kind of case.

I would not want to risk my or others lives to saving a few bucks.

 

[Kendog 170]

So let's say you use a not specifically designed for the application seal. Now let's say you are driving and the brakes fail. Now let's say you kill someone.

Lawyers love that kind of case.

I'm not auguing your opinion. I have researched. You dont want a seal that swells over 20% and the old original seals are rubber. Now we have better materials today as well.It's not all about saving a buck, I'm always looking to better myself for better or worse. Lawyers must love all you guys that put rear disk brakes in your car and never bother with the emergency brake cables . (just an example) Using the wrong seal will swell and keep the piston from working which you would notice pretty quickly. JMO probably not going to happen anyhow, just brought it up to see if anyone else has done it. I probably cut the seals by pressing to hard and not being patient. I do have an overstock of dust boots now lol.

 

[hemi71x]

I guess you have figured out by now, that nobody has ever done what your topic started out to be.
Never is a need to do anything like that.

 

[Kendog 170]

Agreed. I just rebuilt 1 caliper this morning and had no issues at all . Easy peasey . I think I may have used a c-clamp. This time I just pushed them in with the palm of my hand. Sometimes I'm guilty of overthinking things.