DOT 5 compatible caliper o rings

[Ed D.]

There is a site on e-bay selling o rings for c 3 calipers that he claims are DOT 5 compatible. He claims the rubber is EPDM (see link below) Has anyone had any experience with this product?

https://www.ebay.com/itm/186101338360?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20200818143230%26meid%3D2a8a89fe0b014ff8afe67d888bf91158%26pid%3D101224%26rk%3D3%26rkt%3D5%26sd%3D186101240610%26itm%3D186101338360%26pmt%3D0%26noa%3D1%26pg%3D4429486%26algv%3DDefaultOrganicWebV9BertRefreshRanker%26brand%3DUnbranded&_trksid=p4429486.c101224.m-1

[Gary B.]

Re: DOT 5 compatible caliper o rings

Ed,

Have you read Patrick Boyd’s recent post on this topic? I’m not surprised someone on eBay is finally offering DOT 5 compatible O-rings.

https://www.forums.ncrs.org/showthre...on+brake+fluid

I think Patrick’s posting offers a less expensive way to do front and rear calipers.

Gary

PS: Does anyone know the identity of eBay seller “oldvetteman”?

[Joe L.]

Re: DOT 5 compatible caliper o rings

Ed,

Have you read Patrick Boyd’s recent post on this topic? I’m not surprised someone on eBay is finally offering DOT 5 compatible O-rings.

https://www.forums.ncrs.org/showthre...on+brake+fluid

I think Patrick’s posting offers a less expensive way to do front and rear calipers.

Gary

PS: Does anyone know the identity of eBay seller “oldvetteman”?

Gary------

The item description which confirms the EPDM rubber material does not specify if it's peroxide cured. In my opinion, that's critical. I would not want to use any seals, standard lip or o-ring, that were not peroxide cured.

[Patrick H.]

Re: DOT 5 compatible caliper o rings

Gary------

The item description which confirms the EPDM rubber material does not specify if it's peroxide cured. In my opinion, that's critical. I would not want to use any seals, standard lip or o-ring, that were not peroxide cured.

I was surprised the eBay ad didn't mention this specifically, as it seems like whoever wrote it has been reading the discussions on this board.

[Gary B.]

[Gary B.]

[Gary B.]

Re: DOT 5 compatible caliper o rings

Has anybody found "Peroxide Cured" master cylinder seals?
Gary Bosselman

[Owen L.]

Re: DOT 5 compatible caliper o rings

The item description which confirms the EPDM rubber material does not specify if it's peroxide cured. In my opinion, that's critical. I would not want to use any seals, standard lip or o-ring, that were not peroxide cured.

Didn't Patrick's testing reveal practically no difference between the peroxide and sulfur cured EPDM?

[Gary B.]

Re: DOT 5 compatible caliper o rings

Has anybody found "Peroxide Cured" master cylinder seals?
Gary Bosselman

Gary,

That is the key question. Having DOT-5 compatible caliper O-rings solves only part of the problem. And those with calipers that use lip seals have the whole problem still to solve.

Gary

[Gary B.]

[Owen L.]

Re: DOT 5 compatible caliper o rings

Owen,

In Patrick’s original thread, I posted this information from a website that talked about the differences between peroxide vs sulphuric curing.

Thanks for reposting that Gary -- I had forgotten it. While peroxide is preferable, didn't sulfur-cured perform as well? One more thing, how hot do calipers get?

[Gary B.]

[Patrick B.]

Re: DOT 5 compatible caliper o rings

Owen, I completely agree with Gary. While the sulfur cured EPDM looked ok also in my experiment, Gary's additional information convinces me that all O-ring conversions for calipers using DOT5 should use peroxide cured EPDM. Peroxide cured EPDM o-rings are easy to buy from the oringstore.com, and for less than $3.00 a caliper extra, I think they garrantee that you will not need to do the job twice. That said, I would buy any master cylinder kit that the manufacturer says uses EPDM seals. I don't think you would ever find out the curing process of the seals, and the temperature of the master cylinder is not a factor.

[Gary B.]

[Patrick B.]