Looking to source the small O rings that seal the e-brake actuating plunger within the rear calipers. It's small, about .580" outside diameter, with .060" section.

Please confirm which O ring material is friendly to brake fluid?

Last edited by George P
Original Post

I use Viton- a flourocarbon rubber- for everything around my house and shop, including garden hoses. It is proof against anything  liquid in a car. Stay far away from butyl or neoprene rubber which are undependable even with plain water. McMasters-Carr has o-rings- NOT made in China-, and if you run into an oddball size, it's possible to make your own! There are build-your-own o-ring kits available. In the outer space biz, NASA contractors routinely use bulk o-ring stock with the ends carefully super-glued together to create gigantic o-rings for sealing 10+ ft OD segmented booster rockets. This works best for non-moving o-rings but if the motion is slow, it also works on other types. I once fixed a badly designed Camaro master cylinder with a second o-ring seal for backup on a modified moving piston, and my glued o-ring held pressure for decades. There's a POCA newsletter article way back in the web archives on this, with photos.

I don't think Viton (flurocaron) would be the best.   the recomended materail for brake fluids would be EPDM


as for size, using the parker handbook ORD 5700 would let you see what sizes are available.

closest to your dimensions would be a -013 which is 0.070 CS X 0.566 OD

brake o ring


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Last edited by jfb05177

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