C3 70 vacuum controls

[Jim K.]

WHen I first start my car, the wiper door sometimes raises, then lowers. Also, lately I have noticed that when I turn the car off, the right headlight is raised. Yesterday while flushing the radiator, the headlight slowly raised at idle, and would go back down with some revs. Is this a check valve issue orsomething else?
Thanks!
Jim

[Alan S.]

Re: C3 70 vacuum controls

Hi Jim,
It sounds to me like you have a slow leak on the 'control' side of the vacuum systems; the side made up of the small hoses, switches and relays. The actuators aren't receiving the proper 'signal' to remain closed before they receive enough vacuum to move to open.
Perhaps you may want to search the archives for Jack H.'s posts on this subject; search for 'winking' and 'dancing'. That is kinda what the 3 doors do!
Regards,
Alan

[Edward J.]

Re: C3 70 vacuum controls

Jim,My 72 had the same problem and it ended up being the vaccum switch under the pass side wiper, the button on the top was broken and cauing the w/door to cycle up and down on start-up. check it out.

[Jack H.]

Re: C3 70 vacuum controls

The operation you describe is not typical of correct original factory production, but it's not uncommon on used/older cars that have vacuum system integrity issues (age and lack of proper maintenance).

It can be caused by a number of things and there's no 'correct' replace this/check that answer. You have to walk through each vehicle with troubleshooting knowledge to find and fix all of the possible cause factors.

BTW, the RH headlight and the wiper door 'share' the same vacuum system servo path. So, it's not uncommon to see 'funnies' in both of these control surfaces...

[Jim K.]

Re: C3 70 vacuum controls

Thanks Jack, you are always there to bail me out. (Thanks to the other to gentlemen too( Alen and Ed)!). Everything was working fine since I replaces all the hoses and a few components, then once I decided to sell her, she acts up... I know it's just a "car" but I bet she knows...