Help wit Hideaway Headlights on 1968 GTO

[Big Dave]

My 1968 GTO has one headlight door that will not stay closed when engine is off (driver side) I've changed the actuator, vacuum lines, check valve and inspected the vacuum canister. what have I missed. This thing is driving me crazy!

[silver_bullet]

There must be a slow leak somewhere Dave....that allows it to bleed off and iirc, spring tension opens it if there isn't enough vacuum in the actuator....I would think about putting a dab of grease on each vacuum connector to see if that helps....

[Dan Barlow]

Maybe put a little air pressure on it and spray with soapy water .

[Big Dave]

Thanks guy I will try your suggestions and let you know the out come.

[Monster]

How quickly does it open after the engine is shut off ... immediately, after 5 minutes or 30-minutes or longer ?

[Big Dave]

opens immediately.............have any ideas Steve?

[silver_bullet]

Did you say that you replaced the check valve?

[anotheridiot]

I have a check valve I changed but had to plug in backwards to keep the heater controls working in a 99.

[Big Dave]

Yes replaced the check valve

[fatguyzinc]

have someone who smokes cigarettes/cigars blow smoke into one of the vaccum tubes--
ive found MANY an undetectable leak that way after a few minutes of puffing smoke into
the system, it will bleed out any/all pinholes and/or leaks....

[Big Dave]

Thanks fatguyzinc good suggestion only I don't know anyone who smokes but ask around.

[Monster]

opens immediately.............have any ideas Steve?

Being an older car, lots of people could have messed with the front end, instilling alignment problems with the hideaway headlights, especially when removing the endura nose piece and/or bumper. The headlight mechanisms, the vacuum actuators and both sets of inner and outer pivot brackets, are not attached to the core support or the fenders; they are mounted directly to the bumper.

The correct service procedure for bumper removal is to disconnect the electrical and vacuum connections, then remove the 4 bolts that attach the bumper mounting brackets to the frame horns. You also have to loosen the two clamps at the upper, outer corners of the bumper. The bumper assembly is removed from the vehicle, then the headlight assemblies and mechanisms are removed from the bumper.

Is this what you've got ?

[Big Dave]

Yep that's it Steve

[Monster]

With you saying that you've already changed the actuator, vacuum lines and check valve ... First I'd try to identify a vacuum source issue, by swapping around the lines. Then I'd start swapping components one-by-one, from side to side, until you identify the culprit assembly. Does the canister have individual nipples or is each side just connected in the vacuum line ?