Pdwa valve

[stagwingnut]

HI all , had reason to disturb my brake fluid pressure to renew rear cylinders , during the rebleed it would appear that the shuttle inside the PDWA valve has moved therefore illuminating my handbrake warning light and the red brake light , Mine is a 77 car ! I know the procedure to reset the shuttle is to bleed the front in my case ,so I duly did this several times but cannot get the shuttle to centralise again , I also repeated the rear bleed again ,still to no avail , so am to assume the shuttle has become stuck or siezed ? I thought there was a way of manually moving the shuttle , with the electrical switch removed , but doesn't seem possible on my PDWA , I've done the electrical circuit testing ,it's definatly the shuttle that's completing my electrical circuit to energise the dashboard lights . Any ideas gents thx Graham

[Lingen]

Graham. Firstly unplug the wire from the plastic switch on the PDWA unit, to check that the dashboard light goes out. If it doesn't then it isn't the problem you think it is. If it does go out, then unscrew the switch from the brass union, which will give you access to the side of the shuttle. Half way along it is a groove into which the pin of the switch should normally rest. It is just about possible with a very small screwdriver to lever the shuttle in either direction until you can feel the groove is in the correct place beneath the switch pin. I have always found this method much simpler than the hit-and-miss hydraulic one.
Mike.

[SaskStag]

It is useful to have the system working, as it did pick up there was a small leak after some brake work I did. I nipped up the offending nut, but shuttle wouldn't go back, light still on and I knew the brake system was tight. Tried the ROM technique and it didn't work. Tried a small screwdriver as recommended, but not successful for me. Our club mechanic just told me to stamp on the brakes hard a few times (somewhere safe of course) and that worked.
Tanya

[MandM]

Graham. Firstly unplug the wire from the plastic switch on the PDWA unit, to check that the dashboard light goes out. If it doesn't then it isn't the problem you think it is. If it does go out, then unscrew the switch from the brass union, which will give you access to the side of the shuttle. Half way along it is a groove into which the pin of the switch should normally rest. It is just about possible with a very small screwdriver to lever the shuttle in either direction until you can feel the groove is in the correct place beneath the switch pin. I have always found this method much simpler than the hit-and-miss hydraulic one.
Mike.

That is what I did, then I made one of these for next time, keeps the shuttle central during bleeding.
P1060689.jpg

[stagwingnut]

Thx gents for answering , lingen's method has worked for me using a watchmaker size screwdriver ,I was able to slide the shuttle into centre position !! Thx Mike , I like your tool MandM ,will bear that in mind for next time !!! Regards Graham