Brake Fluid Issue

[Joel K.]

Back in 1979, I had Stainless Steel Brakes Corp. sleeve the calipers on our '65. Sent the calipers back to SSBC in 1990 for refurbishment and did that again earlier this year. Also this year, had the master cylinder rebuilt and replaced all lines and hoses. After installing everything I filled the master cyl. with DOT 5 silicone fluid (which I've been using since 1979 without any problems) and was letting the system sit a few days before bleeding the brakes. After a day, I noticed a puddle of fluid under the left front. Couldn't tell where the leak was so I contacted SSBC for advice. Their reply: "Just recently, within the last year or two, have we seen silicone brake fluid affecting seals. Once we looked into why this has started happening is when we discovered that peroxide curing has gone away from most manufacturers of seals. Turns out that the manufacturing costs have sky rocketed to produce the peroxide seals. Making the seals difficult to find and purchase." Interestingly, only one caliper is leaking; I pulled it and checked behind the boots on the pistons and they were dry. Wonder if anyone else has experienced this problem?

[Stephen C.]

Re: Brake Fluid Issue

Back in 1979, I had Stainless Steel Brakes Corp. sleeve the calipers on our '65. Sent the calipers back to SSBC in 1990 for refurbishment and did that again earlier this year. Also this year, had the master cylinder rebuilt and replaced all lines and hoses. After installing everything I filled the master cyl. with DOT 5 silicone fluid (which I've been using since 1979 without any problems) and was letting the system sit a few days before bleeding the brakes. After a day, I noticed a puddle of fluid under the left front. Couldn't tell where the leak was so I contacted SSBC for advice. Their reply: "Just recently, within the last year or two, have we seen silicone brake fluid affecting seals. Once we looked into why this has started happening is when we discovered that peroxide curing has gone away from most manufacturers of seals. Turns out that the manufacturing costs have sky rocketed to produce the peroxide seals. Making the seals difficult to find and purchase." Interestingly, only one caliper is leaking; I pulled it and checked behind the boots on the pistons and they were dry. Wonder if anyone else has experienced this problem?

Joel,

Were you able to find the correct peroxide seals? I am running into a problem with the rear O-ring on my proportioning valve. It started to leak over the winter. I have rebuild kit but I am not able to determine if it is one that was treated with peroxide or not. Thanks for your reply.

Steve

[Timothy B.]

Re: Brake Fluid Issue

Joel,

Many times when these calipers leak it's from sitting and the weight of the little piston will flat spot the lip seal causing the leak. The fix is to pump the pedal at different times during idle periods causing the seal to be forced up against the sleeve keeping it round.

I don't do this because I always forget and if mine leak I just buy a seal kit and fix, only takes a few minutes. I have never had any problems with silicone fluid.

[Joel K.]

Re: Brake Fluid Issue

Joel,

Were you able to find the correct peroxide seals? I am running into a problem with the rear O-ring on my proportioning valve. It started to leak over the winter. I have rebuild kit but I am not able to determine if it is one that was treated with peroxide or not. Thanks for your reply.

Steve

Steve,
I've not actually had a chance to look for the peroxide seals. In e-mail exchanges with SSBC, they said the seals are extremely hard to find, so I'm not very hopeful. Still, worth some checking. If I do find anything, I'll post results here.

[Joel K.]

Re: Brake Fluid Issue

Joel,

Many times when these calipers leak it's from sitting and the weight of the little piston will flat spot the lip seal causing the leak. The fix is to pump the pedal at different times during idle periods causing the seal to be forced up against the sleeve keeping it round.

I don't do this because I always forget and if mine leak I just buy a seal kit and fix, only takes a few minutes. I have never had any problems with silicone fluid.

The system was just reinstalled on the car and the fluid was only in the system a day or two when the leak showed up. I did pump the pedal a few times after filling the master cylinder. Thanks for the tip, though.

[Joel K.]

Re: Brake Fluid Issue

Steve,
I've not actually had a chance to look for the peroxide seals. In e-mail exchanges with SSBC, they said the seals are extremely hard to find, so I'm not very hopeful. Still, worth some checking. If I do find anything, I'll post results here.

Well duh! In light of the above comment, why don't I start searching here -- anyone on the forum had any luck tracking down peroxide-treated brake caliper seals???

[John F.]

Re: Brake Fluid Issue

Steve,
I've not actually had a chance to look for the peroxide seals. In e-mail exchanges with SSBC, they said the seals are extremely hard to find, so I'm not very hopeful. Still, worth some checking. If I do find anything, I'll post results here.

So they're shipping seals that are not compatible with Silicone brake fluid!?

[Paul J.]

Re: Brake Fluid Issue

This might help.

http://adlersantiqueautos.com/articles/brake1.html

[Terry M.]

Re: Brake Fluid Issue

Interestingly, only one caliper is leaking; I pulled it and checked behind the boots on the pistons and they were dry. Wonder if anyone else has experienced this problem?[/COLOR]

If the leaking caliper was dry behind the boots, where is it leaking?

[Joel K.]

Re: Brake Fluid Issue

I wish I knew, Terry. At this point, I have not been able to pinpoint exactly where the leak is. My comments about the seals are based on my email exchanges with SSBC. Still working on trying to figure out if there is somewhere else, but all I know at the moment is that the pistons behind the seals were dry.

[Joel K.]

Re: Brake Fluid Issue

So they're shipping seals that are not compatible with Silicone brake fluid!?

John,

The exact reply from SSBC regarding why they sell silicone fluid: "We still sell the silicone brake fluid because people are still using it in there vehicles that have the correct seals. Many vehicles have the peroxide seals that have never been changed out to new non-peroxide seals. So we still sell to who needs the fluid." I just wish they'd advised me when they sent the calipers back that the seals weren't compatible with silicone fluid.

[Timothy B.]

Re: Brake Fluid Issue

Up until now I could not tell you what a peroxide seal is.

I always go the auto partsd store and get the Dorman seal kit and never had a problem. I also use silicone fluid.

[Joel K.]

Re: Brake Fluid Issue

Up until now I could not tell you what a peroxide seal is.

I always go the auto partsd store and get the Dorman seal kit and never had a problem. I also use silicone fluid.

I was at Carlisle today and spoke with several brake vendors, none of whom ever heard of peroxide-treated seals either. I think I need to kick it up a notch at SSBC and talk with someone about what their rep is telling me. Still only one caliper leaking, too. Stay tuned...