Wiper Door opens and closes when starting

[Bob H.]

I was about fed up trying to find where I was losing vacuum causing the door to open and close upon turning the car off. Everything was replaced new when restored 8 years ago and the car sit. Using mt vacuum pump, I determined the vacuum relay was leaking. Simple fix but still had the problem. tested actuator, wiper safety valve tested good. so I put a check valve in front of the safety valve and vacuum held, Tested the override switch as good. I then managed to put the check valve in front of the wiper door control solenoid and the problem came back. So it turns out what I think is the most difficult part to get to is leaking. It looks like they are out of stock at most places and at least temporarily discontinued but I think I found one and will know tomorrow. Is it common for them to leak? Everything works perfectly except the door popping up at startup

[Patrick H.]

Re: Wiper Door opens and closes when starting

The wiper door control solenoid - are you referring to the one in the trough by the windshield?
If you have your original, try it, or send it to Bob Demmel to be restored. The vast majority of the reproductions leak due to a problem in manufacturing. Only the new one from Dave J over on CF seems to be any good. You can buy direct from him.

If you’re buying the usual reproduction from most of the vendors, you’re not going to be happy.

[Mark E.]

Re: Wiper Door opens and closes when starting

The wiper door control solenoid - are you referring to the one in the trough by the windshield?
If you have your original, try it, or send it to Bob Demmel to be restored. The vast majority of the reproductions leak due to a problem in manufacturing. Only the new one from Dave J over on CF seems to be any good. You can buy direct from him.

If you’re buying the usual reproduction from most of the vendors, you’re not going to be happy.

I think he's talking about the solenoid mounted near the tach.

[Patrick H.]

Re: Wiper Door opens and closes when starting

I think he's talking about the solenoid mounted near the tach.

That's why I asked for clarification. Let's let him answer.

[Bob H.]

Re: Wiper Door opens and closes when starting

Yes, the solenoid behind the tach

[Patrick H.]

Re: Wiper Door opens and closes when starting

Check first to see if it's one of the hoses for that solenoid, or if the connectors might be cracked.
Or, the hose is a bit loose on the solenoid.

The up-and-down door usually signals a vacuum leak, not a malfunctioning component.

Let us know what you find.

And, I'd still check the one in the wiper trough.

[Mark E.]

Re: Wiper Door opens and closes when starting

If you're having difficulty detecting the source of a leak, use a smoke machine. You can get one under $100.

Then for an operational check, connect a vacuum pump using a long vacuum line so the pump is far away from the car. This enables you to energize the system in a quiet environment so you can hear leaks and problems.

[Bob H.]

Re: Wiper Door opens and closes when starting

the wiper door solenoid behind the tach has a slow leak. Tried taking apart and cleaning it. Improved but still has a slow leak over time so I am replacing. Just glad to find the issue. Still may invest in the smoke machine would have saved a lot of time.