You are here:

Triumph Repair/Follow-up Question on 79 Spitfire PDWA


Hey Howard, thanks for the explanation on what a PDWA actually does and how to recenter it.  When I had the switch out of my PDWA and looked inside at the grooved piston, I noticed there was seepage in there.  Not running out on to the paint but a slight puddle in the switch threads.  Would you consider that acceptable or should that be bone dry in there?  I know new PDWAs don't exist, but I would guess the O rings could be replaced if needed and we know how to find them.  Could air be seeping in over time?  As always, many thanks.

The little piston with the grove in it does have a seal on each end to prevent brake fluid from going out to the electric switch. I believe you can still get a seal kit for the unit so if it were mine I would put a kit in it. If you can't find a kit I would just put a brake fluid resistant "O" ring on each end of the piston to stop leakage as the electrical switch can not be sealed.


Triumph Repair

All Answers

Answers by Expert:

Ask Experts


Howard M. Fitzcharles III


Triumph TR-4 up & Spitfire, and Engine theory


Dealership line mechanic on MG, Triumph, Jaguar for 15 years, Instructor in commercial mechanics school 2 yr. Product information manager for piston and valve manufacture, Instructor & hotline answer man for import car parts importer 15 yrs.

Associate member SAE EAA member

Import Car magazine

ASE Master Auto with L-1 certification up to 2000

©2016 All rights reserved.