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Triumph TR6 - PDWA electrical switch

Does anyone know of a source for the electrical switch in the top of the pdwa? Mine is leaking and I really don't want to rebuild the pdwa right now. I'm hoping its the switch.

And mine only has one electrical connection; it looks in the pictures like at least some have 2 leads. Does anyone know?

Thanks, John
JL Bryan

John
I remember my son needing one for his pickup...I think it was an S-10 around 1990???. When he got it (at the bone yard) it was identical to the one on my 6 and yours:).
Good luck at the bone yard.
Rick
Rick Crawford

TRF has the switches, I replaced mine last year.

If your pdwa is leaking it is time for a rebuild. The switch doesn't have any seal and brake fluid should not be in the center chamber where the swich plunger is.

My early 1974 only has one wire into the plug but the original and replacement switches have two contacts.
wayne

Wayne and John,
My '71 has 2 contacts. Not sure why... The 2 contacts are electrically identical.
Rick C
Rick Crawford

Thanks. I'll call TRF, but what do you do with the extra contact when you only have one lead?

THis is on a 71.

John
JL Bryan

John
Like I said, both contacts are electrically identical...they are actually the same piece of metal kinda looks like O___O with the center line as a strip of flat metal ( connected to both male "Os") which is where the plunger makes contact.
If you have the OE connector the hood just goes over the plastic housing and plugs into either contact ,does not matter which one.
Like I said "My '71 has 2 contacts. Not sure why... " . Only one contact is needed..why 2...?????
Rick C
PS You can actually pull out the piece of metal with needle nose pliers..you will see what I mean.
Rick Crawford

John--Like Wayne said, your problem lies with the PDWA seals, not the switch. Get the PDWA rebuild O-ring kit instead.

Rick O.
Rick Orthen

went to a "used auto yard" to get a replacemnt switch.the "new" switch has changed size and doesn't fit anymore. Plastic will chang over years
dk
DON KELLY

To what does rebuild of the PDWA amount? Is there a kit? Who has it?
db
Doug Baker

Everybody. Doug,check the TRF books for the description of the kit.
dk
Don Kelly

I recently rebuilt my master cylinder and PDWA. After looking around to find the 5/16" 008 EPDM O-rings, I finally bought the minimum from McMaster-Carr. Consequently, I have 98 spares! If you need some O-rings, contact me and I would be happy to share the bounty to fellow TR-6rs.
Kent McAllister

Kent, could you send me 3 or 4? I always screw up at least 1 or 2 of things like that.

Just click on my email above and I'll send you the address.

Thanks for the offer!

John
JL Bryan

Had a little get together and they said my pigtail for my PDWA switch was wierd. Can anyone with a 70 or real early 71 send me a picture of their connector?
don kelly @ earthlink . net
dk
DON KELLY

Kent, I have my PDWA off the car, which means the car is off the road. I hope you can send me those little o rings!

John.

Don, I have a picture of my 71, I'll dig it out and send it to you.
JL Bryan

Kent

boy did you open up with a magnaminous offer

if you could send me 3-4 I would appreciate it! click the link and I will email you my address

thanks

bob
Bob Craske

FWIW, I posted this on John's other thread. You can buy the PDWA o-rings at Home Depot in the plumbing department for less than a $1.

Jim
Jim Vandenberg

Jim, just be careful on the O-ring materials. Typically what you find in hardware stores and auto parts stores in the generic O-ring kits are Buna-N. EPDM is resistant to brake fluid.

http://www.sisweb.com/vacuum/o-rings/buna.htm or any of the chemical compatibility charts will give suitability for elastomers for different solvents.

Kent
Kent McAllister

Home Depot offers Danco brand o-rings in the size #36 (I think) which is just a tad larger (1/16") cross section than original. They are made of Viton as per their tech support online email response which also indicated their seals are for potable water applications only. Viton is not listed on the package anywhere. I then checked chemical reference for compatibility of viton and silicone oil, which turns out to be excellent. I then soaked a couple of them in the Silicone Brake Fluid from TRF ( manu. North American Oil Company) for about a month and checked the dimensions again with caliper. All appeared to be in order and no swelling. Did not notice any softness either.

Installing the piston in the PWDA was a bit tight and I may have shaved tad of the viton oring as I saw a small sliver of rubber in the port where the switch mounts. I had lubricated it with silicone fluid prior to assembly and it was rather tight so I left it alone.

I just put all my brakes back together last weekend and was able to gravity bleed the system for the most part by my self. Then pumped VERY slowly (5 seconds down, hold for a second, and 5 seconds up)about 30 times on each wheel. I used air to blow out all the old residual glycol before filling with silicone and let the new fluid sit for about 10 minutes before starting to bleed to allow air bubbles to dissipate. Pour it slowly into the reservoir down a clean rod to minimize bubbles.

I checked the piston position after bleeding and hard pendal pressure and it is still in the middle and there is no puddling of silicone in the switch port.

Just my experience, Good Luck.
MRankin
MRankin

Kent's O rings came yesterday and I installed them on the piston. Perfect fit.

With the piston reinstalled, and as near as I can tell, centered, there does not appear to be any leakage. After cleaning the PDWA up real good, I blew as hard as I could into the brake line openings, while plugging the opposite opening and/or where the cap goes. No air got through.

How do you make sure the piston is re-centered after the bleed the brakes? Its pretty hard to see much in that little teeeny hole when you take the electrical switch out.

Thanks, Kent

John
JL Bryan

Would any of you care to advise me how to get the @#&%$* plunger out of the PDWA? Got the O rings, removed the electrical connection and the plug; now what. I thought maybe the plunger would just come out with a gentle thump. Not so!! Maybe I presumed too much and should not attempt to replace the O rings. Also, the plug was quite dirty as if there had been some metallic contamination in the system. What solvent is preferred/recommended to clease the inside of the PWDA? Thanks,
db
Doug Baker

Plug off the two ports closest to the open end with bolts of the appropriate size and thread pitch of the PDWA and then one side of the other two. Set up a nicely cushioned catch pad and take your compressed air nozzle, stick it into the remaining open port and give a quick push on the handle while aimed at the catch pad. It will come out with amazing speed.
SteveP

Thanks Steve,
I'll try that method. What about cleaning??
db
Doug Baker

Doug, mine came right out with a little gentle thumping on the work bench.

Brake cleaner should clean it out perfectly.

By the way, the PDWA looks really nice after a little Brasso.

I still want to know how you can be sure the piston is centered after you bleed the brakes.

John
JL Bryan

John,
Regardless of what style piston you have, as I heard there are a couple/few types, there will be a narrow section right in the middle about 2mm wide. Then on each side of the very center the diameter will start to get larger. This larger diameter shoulder is what hits the switch peg pushing it up when the switch gets off center due to pressure differential in the brake lines. You should be able to see and feel the narrow section of the piston with an ice pick or similar (elecrical switch removed, of course). If it gets off center after bleeding, you can use the ice pick to persuade the piston to its center again and re install the switch.

I had to take mine apart again as I had silicone fluid seeping out of the switch top. So I guess the sliver of rubber I saw was a shaved o-ring. I used the same type Danco #36 viton o-rings but this time I used narrow needle nose pliers to twist and slowly push the piston in hoping not to shave it. Have not been able to bleed it all again yet. Hopefully this weekend.
Cheers,
MRankin
MRankin

John
Thought I would post this on this thread since it is titled PDWA.
Those with the CD will find a good article on the PDWA. It contains a good drawing explaining every part.
Look under: Procedures/mechanicals/brakes/...
Then you might want to look at the shop manual where 70.25.02 #10 explains how to center the piston. A different procedure than has been mentioned here by MR and myself, on your other thread.
Oh Ya... Autosol also does an excellent job in making brass glow.
Rick C
Rick Crawford

Here is a drawing of the PDWA

<img src=http://static.flickr.com/35/104182501_378066ae7b.jpg?v=0>

Rick C
Rick Crawford

Thanks, Rick. I put it back in, and it isn't leaking. Won't know if the warning light is working until I get a new alternator installed. It's always something!

John.
JL Bryan

Rather than start a new thread, I decided to reactivate this one on PDWA. I FINALLY got the damn shuttle, or plunger or whatever it's called OUT. Took about 100# air pressure and then moving the plunger back and forth until it finally broke the corrosion enough to break free. Now the question is what to do with the plunger. I think that I saw one article in which the TR6 owner had "polished" the plunger. Is this recommended and if so how is it done? With polishing compound on a polishing wheel? With a dremel, just with autosol or Brasso and a soft cloth? Then how do I get the inside of hte PDWA clean? Will brake fluid alone suffice or should I soak it in some solvent (what/which) and then wash the solvent out? I'm as yet undecided w/r to DOT 4 or 5 so if I use one to "clean" the PDWA do I then have to clean all that out to use the other in the system? What about the other several brake line connections? Should not they all be removed and thoroughly cleaned also? If so, how? I have all new SS replacement lines, but I'll have to reuse the connections. All comments/suggestions/ideas appreciated. Thanks.
db
Doug Baker

Doug

If I remember, there are o rings that go around the plunger to form the seal to the inside of the PWDA. If that is the case, it is important to not mar the inside of PWDA where it forms the seal with the o ring. I would use a plastic scrubby brush and the brake fluid you had originally in it as it should dissolve the build up. Scrub until satisfied. Plastic should not mar the brass.

if you use DOT5 and had something else before, you need to drain the lines well and then I would use the DOT5 and flush it through each line and wheel cylinder/ caliper to flush out the old stuff through the bleeder valves. Discard the flush material. I don't think you need to pull each one out and hand wash them.

I should mention, I have used a grease gun to get stuck plungers out (master cylinder, slave cylinders, PWDA). I adapted a grease gun fitting to a brake line fitting and use hydraulic pressure (grease) to force the plunger out. It is more effective than air since it doesn't compress like air and the grease helps lubricate the plunger/surface. Safer too as you are not working with a potential projectile from compressible air. The grease gun should be hardy and able to put out good grease pressure.

Michael Petryschuk

Wow! This is an old one. I got new o rings, took it all apart, cleaned it, put it back together and it has worked fine for more than 4 years, since this thread started.

Makes me feel old.
John Bryan

Michael,
The grease gun idea is novel and I easily see where hydralic pressure would work very well. I have all new Master and wheel cylinders, new SS lines throughout but will reuse the union connectors/distribution points and will likely remove, clean, bead blast and powder coat or clear coat before hooking up the new system. I'm leaning to DOT 5 (had 4 before), but as yet undecided. That's still a ways away though so no hurry. I have new O rings for the piston so will rebuild the PWDA.
db
Doug Baker

This thread was discussed between 06/02/2006 and 13/08/2010

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