Strange vacuum issue on my '69 -- any help?

[Paul S.]

The vacuum operated headlights and wiper door on my '69 work great -- exactly how they are supposed to. However, I have one weird thing going on as well:

When I start-up the car, the wiper door starts to open slightly and then moves right back into the closed position. It happens about a second after the engine starts turning over on its own.

Anyone ever seen this before or have any ideas on what might be causing it? With everything else working perfectly right now, I am hesitant to tear the vacuum system apart for what amounts to a minor annoyance, but if possible, I would love to fix this.


Thanks in advance,
Paul

[Anthony F.]

Re: Strange vacuum issue on my '69 -- any help?

Paul,

I had the same problem on my 72.

At the rear of the wiper door actuator, I pulled back the actuator boot and noticed the seal had somehow pulled out of the housing ( from the linkage rod going back and forth? ). I reset the seal and the problem was corrected.

I know the early 69's use a different actuator, so if yours is the older style, this might not work ( I Googled around, but couldn't tell if there is a seal on the earlier type ).

This is easy to check, and if it works, could save you hours of hunting through the 70+ feet of vacuum tubing, etc, under the hood.

Good luck!

[Bob D.]

Re: Strange vacuum issue on my '69 -- any help?

Paul

Your '69 wiper actuator does not have the same type of seal on the back as the later pie plate style has. Yours is internal, but those usually don't leak enough to cause the problem you describe. Try checking the vacuum valve that is dedicated to the wiper side. It may have a leak which is causing the problem.

Bob

[Paul S.]

Re: Strange vacuum issue on my '69 -- any help?

Paul

Your '69 wiper actuator does not have the same type of seal on the back as the later pie plate style has. Yours is internal, but those usually don't leak enough to cause the problem you describe. Try checking the vacuum valve that is dedicated to the wiper side. It may have a leak which is causing the problem.

Bob

Hi Bob,

Nice to hear from you! Do you mean the vacuum valve that is mounted under the hood that you re-plated/rebuilt for me in December? Now that you say that, I think this problem may have started when I re-installed it. Is there any particular area on the value that I should look at for a leak?

I think I have another one that I could throw on as a test, so I will let you know...


Thanks,
Paul

[Bob D.]

Re: Strange vacuum issue on my '69 -- any help?

Paul

If the valve is leaking, send it back. I had a couple of them leak down on me. I will repair and return. If it is not the valve, then you have a leak somewhere else.

Bob

[Paul S.]

Re: Strange vacuum issue on my '69 -- any help?

Hi Bob,

I finally got around to troubleshooting this issue today. It turns out that the valve you restored for me is perfectly fine. It was my original "coffee can" actuator that was leaking. I replaced it with a reproduction, and my wiper door issue was gone!

I would like to ditch the reproduction actuator can and use my original if possible, though... do you restore these too?


Thanks,
Paul

[Bob D.]

Re: Strange vacuum issue on my '69 -- any help?

Paul

Glad to hear you were able to trace the problem. I do restore the coffee can actuators.

Bob