my 72 Vette wiper door closes on wipers at different intervals
 

!972 Corvette wiper door closes on wipers at different positions. I have to keep trying to park them multiple times to get them close to parking in the full close position but rarely can get them in the perfect spot. Door closes quickly and does not wait until the wipers are fully down. Any suggestions as to the culprit.

Did it just suddenly start acting like that? Any history on you working on that system?

no, it has been this way since I bought it back in January

This happened to me (also a 72) yesterday. Got caught in a thunderstorm and the wiper door would shut on the wiper arms at various positions pinching them not allowing them to sweep. Weird thing was when I let off the accelerator the wiper door would open back up and the wipers would return to normal but as soon as I got back on the throttle the door closed again. I'll be testing the various vacuum components this week and will post what I find.

Sounds like it might be caused by the wiper door safety switch, which is underneath the passenger side wiper arm near it's pivot point. It tells the wiper door that the arms are parked and it's okay to close.

Also, Tex, there is a one-way valve so you don't lose can vacuum when you hit the throttle. Yours is either blown or nonexsistant. Reminds me of school busses when I was a kid. Drivers had to lift off gas to make the vacuum wipers go.

It is defiantly the safety switch under the wiper door, passenger side. It pretty much fell apart once I got to it. Does anyone know if the heater hot water shut off vacuum valve for 77 to 79 is the same as the wiper vacuum safety switch on the 72. they both look identical except the hot water valve is half the price for the one that is made in the USA.

It is a vacuum switch.

By the way, does the switch under the steering column work? The pull down knob on the right side of the large round knob controls the vacuum door: if you pull it down (with the car running), the vacuum door should open and stay open. The round knob turns the wipers off (so that you can stop them at the top of the cycle when you need to change the blades).

Not certain as I have already removed the wiper safety switch. For whatever reason I didn't realize the pull knob on the right moved, I was only aware on the knob to turn off the wipers. Still learning...
does the black knob on the left do anything?
I have had my hands full rebuilding the front suspension and steering componets. Now that that that is done I have finallyt been able to get it on the road and started on other fixes.

The black pull knob on the left is the override for pulling the headlights up/open. So that you can adjust them, change the headlights, things like that....

it was the safety switch. thanks for the help.