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TR6 Pressure differential warning assembly PDWA valve


Luke Skywalker
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All the brake fluid has leaked out of the large reservoir on the back side of the master cylinder. It came out of the top of the brass PDWA switch. I can't see that TRF sells a repair kit but Moss has two styles. It looks like mine has the lip seals so I'll have to convert to the O-ring style kit. Two questions

Can I get the correct lip style seals, and who has them?

Do I need to get a new switch because it leaked out through the top of it, should the switch also have a seal in it? My thinking is that the switch is fine and was never designed to hold back fluid, that's the lip seals, or O-rings job.


Great Pumpkin - R.I.P
AFAIK the lip type seals have been NLA for a long time. There was a nice article on how to make a replacement shuttle to take common O-rings, but I think the author asked to have it taken down due to potential liability.

The switch doesn't seal. As long as it still works electrically, no need to replace it.


Luke Skywalker
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Thank you Randall, the switch still works fine. The kit Moss sells includes a new shuttle for the O-rings.


I believe the article Randall mentioned is on the Buckeye Triumph web site. Take a look at the two links below.



If you cannot get the o-rings from a local supplier, you can order them from McMaster-Carr (www.mcmaster.com). Just make sure you order EPDM, not Buna or Viton.

EDIT: I forgot to mention that if you do start having trouble with the PDWA switch, one for a '67-'69 Ford Mustang is the common replacement (Ford # C8AZ-2B264-A). See the related thread linked below.


Luke Skywalker
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Thanks Doug interesting articles, I'll check McMaster
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