Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

[Gary B.]

Re: Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

Tom,

Someone needs to definitively confirm if AS568-011 is correct for the very small ones between caliper halves.

Gary

[Leif A.]

Re: Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

Leif— It is certainly ok with me if you want to talk to LS about this. I would think they prefer to give their customers the most useful product they can. The solution to the DOT 5 issue is so simple, and they can gain a competitive advantage over CSSB by using the right o-rings.

Patrick,
Just heard back from Ken at Lone Star Caliper. Below is his response...his manufacturer needs additional information. After you give me this info, in my next communication with Ken I will ask him if he knows what type of o-rings his manufacturer is currently using.

My manufacturer has some questions
1. Send them the attached Chart.
2. Ask them if they are testing in SAE Referee Brake Fluid - Part RM -66-03
3. Ask them to state exacting what Brake fluid they are testing in. ???

[Patrick B.]

Re: Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

Patrick,
Just heard back from Ken at Lone Star Caliper. Below is his response...his manufacturer needs additional information. After you give me this info, in my next communication with Ken I will ask him if he knows what type of o-rings his manufacturer is currently using.

My manufacturer has some questions
1. Send them the attached Chart.
2. Ask them if they are testing in SAE Referee Brake Fluid - Part RM -66-03
3. Ask them to state exacting what Brake fluid they are testing in. ???

Wow Leif, I think we just discovered the source of the myth that DOT 5 fluid changed over the years and caused all the problems for which manufacturers had to protect themselves by prohibiting the use of DOT 5 in their products.

The salient facts about our tests are: that tested in Carquest DOT 5 fluid their O-rings swelled over 14% in section diameter and became softer, that tested in Valvoline DOT 4 fluid their O-rings swelled only 1.4% in section diameter and did not appear to be softer.

The most salient fact was that EPDM o-rings tested in Valvoline DOT 4, Carquest DOT 5 and experimental 1977 Dow Corning silicone fluid swelled zero to less than 1% in section diameter and showed no softening.

The chart from the manufacturer was about tests in DOT 3 fluid (SAE J1703). Curiously, it does not mention what rubber was being used. Was it the mystery rubber used in their inferior o-rings? Who knows. Identifying these fluids as J1703 fluids means that they all passed the SAE J1703 test. Recent versions of this standard include EPDM as a rubber test sample so presumably all these fluids are compatible with EPDM. Does the manufacturer consider any of the results in their chart to be a failure. Who knows?

What is the purpose of this chart that does not identify what rubber is being tested and whether the variation in results are significant enough to say that the rubber is compatible with some fluids and not others? All fluids that satisfy the current SAE J1703 standard can be certified as compatible with EPDM rubber. The only purpose I see is to suggest that fluid differences invalidate the conclusions of the we have made from our limited tests. That was the Lone Star's position when we started the discussion here a couple of years ago.

This manufacturer knows that its product will fail in DOT 5 fluid. Its chart could be interpreted to say its product is marginal in some DOT 3 fluid. We are have interpreted our tests to mean that we could use DOT 5 fluid in o-ring calipers if peroxide cured EPDM o-rings were used. Manufacturer-- please show us a DOT brake fluid that is NOT compatible with peroxide cured EPDM rubber. We doubt that it exists.

Lief-- This manufacturer's response reinforces my view that the only way we can use DOT 5 fluid in o-ring calipers with long term confidence is throw away his inferior o-rings and substitute known EPDM o-rings.

[Leif A.]

Re: Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

Wow Leif, I think we just discovered the source of the myth that DOT 5 fluid changed over the years and caused all the problems for which manufacturers had to protect themselves by prohibiting the use of DOT 5 in their products.

The salient facts about our tests are: that tested in Carquest DOT 5 fluid their O-rings swelled over 14% in section diameter and became softer, that tested in Valvoline DOT 4 fluid their O-rings swelled only 1.4% in section diameter and did not appear to be softer.

The most salient fact was that EPDM o-rings tested in Valvoline DOT 4, Carquest DOT 5 and experimental 1977 Dow Corning silicone fluid swelled zero to less than 1% in section diameter and showed no softening.

The chart from the manufacturer was about tests in DOT 3 fluid (SAE J1703). Curiously, it does not mention what rubber was being used. Was it the mystery rubber used in their inferior o-rings? Who knows. Identifying these fluids as J1703 fluids means that they all passed the SAE J1703 test. Recent versions of this standard include EPDM as a rubber test sample so presumably all these fluids are compatible with EPDM. Does the manufacturer consider any of the results in their chart to be a failure. Who knows?

What is the purpose of this chart that does not identify what rubber is being tested and whether the variation in results are significant enough to say that the rubber is compatible with some fluids and not others? All fluids that satisfy the current SAE J1703 standard can be certified as compatible with EPDM rubber. The only purpose I see is to suggest that fluid differences invalidate the conclusions of the we have made from our limited tests. That was the Lone Star's position when we started the discussion here a couple of years ago.

This manufacturer knows that its product will fail in DOT 5 fluid. Its chart could be interpreted to say its product is marginal in some DOT 3 fluid. We are have interpreted our tests to mean that we could use DOT 5 fluid in o-ring calipers if peroxide cured EPDM o-rings were used. Manufacturer-- please show us a DOT brake fluid that is NOT compatible with peroxide cured EPDM rubber. We doubt that it exists.

Lief-- This manufacturer's response reinforces my view that the only way we can use DOT 5 fluid in o-ring calipers with long term confidence is throw away his inferior o-rings and substitute known EPDM o-rings.

Patrick,
Thank you, as always, for your precise, educated explanation. This is being passed along to Ken.

[Patrick B.]

Re: Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

Leif - You are being kind. My last comment was a bit of a rant. I considered questions like, "did you use a [DOT 3] reference fluid?" to be irrelevant attempts to throw stones at information we gathered about EPDM compatibility with DOT 5 fluid. It made me angry.

This morning I read their questions again with a cooler head. We knew that EPDM rubber was the most common material used for brake system seals for cars using DOT3 and DOT4 fluid. Early on we had discussed the NHTSA notice of proposed rulemaking that said so and proposed adding EPDM rubber to the fluid compatibility tests. SAE did so with updated standards J1703, J1704 and J1705. Lone Star's questions did not seem to be about silicone fluid but rather about DOT 3 fluid. They seemed to be questioning the compatibility of EPDM rubber o-rings with DOT 3 fluid. Despite apparently having a testing lab involved with their manufacturer, they were acting like they did not know that EPDM was the ordinary rubber used in DOT3 and DOT4 systems and that our suggestion of using EPDM o-rings so that their calipers could be used DOT5 fluid would open them up to problems with DOT3 fluid. Lone Star must not be aware that its 66 master cylinders like the one Gary Beaupre sent seals from use EPDM rubber that performed well in DOT5. Brake fluids labeled SAE J1703 and SAE J1704 (which are the same as DOT3 and DOT4) have been tested for compatibility with EPDM rubber.

Unfortunately, NHTSA did not update FMVSS no.116 to match the EPDM rubber tests in SAE J1703, SAE J1704 and SAE J1705. SAE J1705 requires compatibility of silicone brake fluid with EPDM rubber. I looked at the labels of all the silicone brake fluid bottles on the internet hoping to find ones labeled as SAE J1705 fluid, however they were only labeled as FMVSS No. 116 compliant. The only reason we had to test the EPDM o-rings in silicone fluid was that FMVSS No.116 was never updated to include EPDM as a test sample. Now we know it performs fine in new Carquest DOT5 as well as very old experimental Dow Corning fluid, and Mark Lincoln's tests showed that there is very little chemical variation among several DOT5 fluids. It is obvious that EPDM o-rings are compatible with DOT3 and DOT4 fluid, and our tests, as limited as they are, show they are also compatible with DOT5 fluid. This manufacturer may not accept any of this, but I do not care. I already bought the Lone Star calipers, and I will improve them with my own peroxide cured EPDM o-rings.

[Bob W.]

Re: Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

Patrick- you should make kits and sell them in the driveline and here online.

[Gary B.]

[Patrick B.]

[Gary B.]

Re: Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

Patrick,

Hang onto them until we find out from Mark about performing chemical analysis of the various seals and O-rings.

Gary

[Mark L.]

Re: Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

Analytical testing is in process on the samples that Pat tested in his "lab". Also included are o-rings from a set of calipers rebuilt for me by Lone Star. Stay Tuned.

[Leif A.]

Re: Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

Just as an FYI update, Ken at Lone Star Calipers is in the process of having independent testing done on peroxide cured EDPM o-rings. Results should be back to him shortly.
To quote Ken from his latest e-mail to me: "...we have started the process. Will let you know test results very soon. I am praying this works cause this would save us a lot of headaches and make a lot of customers happy. We are very hopeful. Thanks"

[Gary B.]

[Leif A.]

Re: Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

Leif,

Wow… I’ve been pondering your posting for a few hours now. My first reaction was, well it’s about time. It’s rather late to the game, I’d say. My first question was, why now? And why not five, ten, or fifteen years ago when the issues with leaking seals and DOT 5 first came up? I’m guessing it has to do with the fact that people like Patrick Boyd, Mark Lincoln and a number of other people on this board and the Corvette Forum have done and are still doing what should have been the responsibility of proactive vendors. I’m certainly glad that Lone Star is finally looking into this issue in a serious and professional way. So, I’ll count that as a win, however belated it is.

Gary

Gary et al,
Just received this e-mail from Ken @ Lone Star...

'I have sent them off to a company that does independent testing and I am not exactly sure how long his process is going to take. I just did this when we got back form this last show. We are testing in house and so far so good but again to make such a big change I want to make damn sure they are tested completely and no stone left unturned. The company I sent it does DOT testing and can do long range testing to make sure they will hold up for years to come. Again this is not something you can do in just a few weeks. As soon as I have something to share I will let you know. I will be out out town for shows the next 2 weeks then back in the office and hopefully we will have something then. Thanks,"

[Patrick B.]

Re: Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

It is surprising that Lone Star is so concerned that peroxide cured EPDM may not be a good type of rubber for brake components when it is the brake industry standard while selling products made of rubber they can't even identify.

[Gary R.]

Re: Testing Lone Star Caliper O-rings in DOT 4 Brake Fluid

I think you nailed it and I could add some comment on QC but will stay out of this and see where it goes.