72 bucket of parts

O.K. so the wiper door system has 3 major parts it looks like. The vacume can that moves the door. The valve that has 3 large and 1 small vacume line going to it. And the piece under the door that has 3 vacume lines going to it. The can that moves the door I get. I applied vacume to both sides of the can and it seems to work fine. The valve I'm not sure I under stand. I think when you apply vacume to the small line that causes the switch to move and direct vacume to open the door. Remove the vacume and there is a spring that redirect the valve to close the door? No clue what the piece is under the door. Can anyone confirm my understanding of the valve, and tell me what the other valve is? One more thought. Has anyone put a more aggresive cam in one of these cars and lost so much vacume that you had problems with the vacume operated stuff? If so, how did you solve the problem?

Kelley

HOOAH

Kelley,
Going through this very thing as we speak on my 71. Bout to pull my fricken hair out. In short, I thought I had it figured out but I can only get the door to open or close by switching the large green and large red on either side of the can (actuator). Are you saying that the door closer is spring actuated when the vaccum is released? I thought that's the way it worked too. I'm just going to piggy back off your thread to see if I can pick up some pointers myself. Been out in the driveway all day trying to get these wipers to act right.

There's also lines running under the dash to the manual overrides and to a vacuum solenoid.

Terry

7T1vette

The other significant parts are the solenoid valve/switch that mounts to the backside of the tachometer and the wiper door interlock safety valve which is mounted in the right side of the wiper well and senses the right wiper being in the 'parked' position. The "can" is the servo for the wiper door; the 'thing' with the 4 hoses on it is the "relay" that sends the proper signal to the 'can'; the solenoid/switch sends the ON signal to the relay (once it gets power from the wiper switch); and the interlock valve allows the door to close IF the wipers are parked. Got all that?

Have fun.

...Roger...

Lets start here guys.

HOOAH

Well after today I managed to see some progress. When I turn on the wipers, nothing happens until I push on the vacuum valve (upper left component on the diagram Roger posted) two times. Then the door opens and the wipers kick on. When I shut the wipers off, they stop but the door stays open until I push the valve just a single time.

I thought it was maybe a bad valve but it's brand new and came off my 69 to which the wipers worked fine before I tore it down for the frame off.

Maybe I should remount the vacuum valve under the dash with super long vacuum lines. That way I can play my little push button game each time I need the wipers.

BTW, thanx guys for the help on this issue.

72, I think this answers your question too.

Terry

...Roger...

Just get that valve adjusted right and you should be good. The plunger in the valve must be all the way in when the wiper arm is down completely. Make sure the wiper arm is coming down all the way.

HOOAH

Roger, I dont see any adjustments to be made on the valve. Just three hoses with a spring loaded push button on the top.

Terry

...Roger...

The 2 bolts that hold it on is where the adjustment is done.

72 bucket of parts

Yeah, that makes sense. I will have to go back out and look this afternoon.
Thanks everyone.

Kelley

HOOAH

Ok, got it. Thanx Roger.

Kelley , thanx as well for the thread start.

Terry

7T1vette

The new valves do not have any elongated holes on them to make up/down adjustments as needed. You will have to adjust the wiper blade position [when parked] or remove the valve and elongate the mounting holes so you have some ability to adjust it.

HOOAH

Found that out too. I didnt have the valve mounted yesterday when messing with it. I didn't understand that the wiper arm actually pushes against it to activate the door open or closed. The old valve had the head button, boot and spring completely missing so I never saw the wiper arm contact with the valve button.

Happy to finally say the wipers and door work just fine now. Once again, thanks to the members of the forum another problem solved.

Terry

...Roger...

7T1- I don't think I've ever seen elongated holes,I'll have to dig out some old ones.

Hooah- That pesky valve just does 2 things passes vacuum between the 2 lower ports or doesn't pass vacuum.
Valve pushed in-wiper arm down- vacuum passes through to the relay and the wiper door comes down
Valve up or out- wipers running - no passage of vacuum - wiper door up

HOOAH

Roger,
I was looking at all of the components against a series of diagrams. As soon as you sent yours (from Wilcox), I realized that my valve didn't look like the picture with the cap and boot on it. As soon as i looked at my 69 valve, I came to the conclusion that this may have been my problem all along. That was of course after doing what we call in the Army as "controlled substitution" with known good parts for the last several weekends. Wasn't going to let it take me down but sure was a frustrating venture. Thanks again.

v/r
Terry

72 bucket of parts

Did some more looking on my 72 after the leason on how it all works. My switch under the wiper door is bad. Time to order more parts! Thanks everyone. I figured i wasn't understanding something.

Kelley

72 bucket of parts

Well, got the new vacumn switch and installed it and with a little help all seems to be working as it should. The only issue I can see left with all of that is the fact that my cam is not allowing enough vacumn to build in the system to run everything. Not sure what I am going to do about that. Anyone install an aggresive cam on a c3 and have this issue? What did you do to overcome it?

Kelley

WESCH

Hi

If you are 100 % sure that it is the cam avoiding enough vacuum pressure to build up and not leaks in the system, you may install a vacuum pump and disconnect the vacuum hose from the engine.

Rgds. Günther

BBCorv70

I just installed a new one on mine. The valve does not have elongated holes as you point out but the bracket it fastens to does.