View Full Version : TR6 Pressure differential warning assembly PDWA valve

10-25-2015, 02:25 PM
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.

10-25-2015, 02:58 PM
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.

10-25-2015, 03:05 PM
Thank you Randall, the switch still works fine. The kit Moss sells includes a new shuttle for the O-rings.

10-25-2015, 04:14 PM
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 (https://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.

10-25-2015, 04:47 PM
Thanks Doug interesting articles, I'll check McMaster