c3 vacume system

[MADLT1]

hi guys,i have been in the garage all day working on my 71 vets vacume system,i have replaced the 2 canisters behind the lights,plus the 2 actuators inbetween,the only 1 I have not replaced is the I for the wiper door inside the fender.so what has happened when I turned the engine on is the headlight doors rose up but very slowly,but they would not pull down?so do I replace the wiper actuator?can I use one of the 2 old actuators that I replaced for the lights?they look the same,but not sure if there is a diferance?or could it be the canisters need more adjustment one way or the other?i have a vacume gauge and I was getting vacume from the tank forward,i will do more testing tomorrow and go over the pluming again,its just so time consumeing,i had to walk away lol,cheers

[bfit]

You have a loose hose at the front of the car or a split hose
In the nose just in front of the hood line .
That what I would start with.
Bfit

[MADLT1]

no I replaced those hoses,now I am thinking it could evan be the headlight switch?ill do some more vacume testing tomorrow

[bfit]

no I replaced those hoses,now I am thinking it could evan be the headlight switch?ill do some more vacume testing tomorrow

Have you got vacuum in the canister before you start the engine
Bfit

[Vettech]

I'll probably be out of order here, but on 78on the res was in the tubular steel section welded between the chassie rails at the front roughly under the lights, I could park, come back a week later, pull the switch and up they came (no engine running). Get some vaccumn & tube and put it straight onto each actuator. One of mine developed a hole in the actuator rubber diaphram so I replaced it as a complete unit. With Vac on each they should, if not siezed or Impeded, come straight up/down. Having said this,  please remember, 71 is not forteau. On a VK Commodore upon heavy accel, all dash A/C outlets would go haywire, I used a black plastic cystern float ball (easter eggy shape) brass fitting each end plus one way valve - instant cheap vaccum reservior. I hope something here helps. Bfit would know better than I, but lumpy cams I believe, may also cause lose of vac.

[77CVT]

Do they work fine with the engine running?

[MADLT1]

they only come up ,wont pull down,allso I have not been able to get wiper door working yet,i will spend some more time on them tomorrow,but I am thinking new relay valve for the wiper door and headlight switch

[sirfixalot]

The control circuit small hose on vacuum valve has no vacuum so the vacuum solenoids are de-energised. The headlites go up when vacuum cut off from the diapram  check the over ride switch under dash or the headlite switch a few years ago there were diagrams on the net with headlite connections back to front. Will only work one way

[MADLT1]

well what I just did was swap out the wiper door relay with one of the old headlight relays,and now it all works,unbeleivable lol,i will buy a new relay and check valve now and that should just speed it all up plus hold vacuume in the resavior tank,thanks for all the input,cheers

[bfit]

The good thing from this you know the system  now
Bfit