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0 Ring For Brake Fluid

I have a vehicle that has a hard plastic line that goes from the clutch master cylinder to the slave cylinder . This line has a connection just outside the bell housing that has an 0 ring that is leaking . What I want to know is if I can get an 0 ring that isn’t affected by brake fluid . I could buy the plastic line which I assume would have an 0 ring on it but it’s $68.00 & all I need is the 0 ring .
Places have 0 ring assortments but I don’t know if they’d work with brake fluid .

Here’s a short summary-

Pretty sure Viton would be OK but the reference above talks about clarifying application.

IMHO brakes are far too important to play games with. I strongly recommend just getting a proper new line w/fittings.

Viton will work well unless you use glycol based brake fluid. If you don’t know, avoid Viton and go with Aflas. This assumes you can find them and afford them. Viton is not cheap and I imagine Aflas is even more expensive.

You want to use a PTFE O-ring.

It’s compatible with brake fluid, and operates within the proper temperature range.


OP is having problems with the clutch hydraulic line, not the brake lines.

Oops! Maxima Mea Culpa!
For that I support trying the O rings suggested.
I plead old age… :stuck_out_tongue_winking_eye:

Thanks , think I can find what I need at that site .

PTFE is a single use O-ring, and it will eventually fail. PTFE will permanently deform (cold flow) under load. With pressure in the line behind it, the PTFE ring is going to leak. It will take a few years, but it will fail before an elastomer ring that is compatible with the brake fluid would.

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If you go the web site I provided, and click on All About O- Rings, look at the temperature ranges of the O-rings that you suggested to use.


EPDM O-rings. Wide temp range, Ethylene Glycol happy and this is what the brake people use. It is softer and more compliant than Viton

To test the o-rings, just in case you get the wrong material, put a little brake fluid in a glass dish and toss in the o-ring you want to use and leave it overnight. If it swells or dissolves… DONT use it! If it looks OK, you are good to use that ring.

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