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Discussion Starter · #1 ·
On my '69, the wiper door will open perfectly but will not close under it's own power. Headlights open properly but alittle lazy on closing. All lines are attached properly. I can't seem to find anything visibly wrong. the only thing I have messed with was removing the wiper arms themselves to recondition them. (still off the car if that matters) Anyone else have this problem before? I understand GM made the door open by default if anything went wrong with the system. where should I start on this DC? Thanks Ya'll !!!
 

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Discussion Starter · #2 ·
I forgot to add this all started while doing a burnout :D When I really got on the gas the door pop'ed up......I DUNNO!
 

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Check the vacuum relay to the actuator. The retract supply hose might be leaking.

:thumbsup:

:agree:

Sometimes the outsides of the vacuum lines look good but the inside is dry and cracked. The way I ensure a good fit, on ALL connections with old hose, is to pull the hose and trim about 1/4" off the end then slip it back into the nipple.

Typically this will buy more time before the lines have to be replaced, and after trimming they seal a lot better. Might solve your problem.

If not, it might be a defective relay.
 

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On my '69, the wiper door will open perfectly but will not close under it's own power. Headlights open properly but a little lazy on closing.
Since both headlights and wiper door are showing symptoms, I suspect your vacuum system check valve.

Easy to check. Remove it from your system and blow into the single large port (the other side has two ports - one large and one small). If you can blow through the valve in this manner, it is bad and must be replaced.

A bad check valve lets your vacuum escape when you open the throttle OR when you shut down your motor. And since both headlight and wiper door systems are "fail safe", they will tend to open or fail to close when you loose vacuum.
 

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losing vacuum

have all new hoses except those under dash, everything
works but system will not hold vacuum. i understand that
it should hold vacuum enough to make lights open at least
once after motor is shut down!!!!


THANKS
B.C. EVANS
 

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have all new hoses except those under dash, everything
works but system will not hold vacuum. i understand that
it should hold vacuum enough to make lights open at least
once after motor is shut down!!!!


THANKS
B.C. EVANS
Either you have a bad check valve (as posted before) The check valve stops vacuum from leaking into the intake manifold after the engine is turned off and maintains vacumm in the reservoir under hard excelleration. Or you most likely have a bad air motor (most likely a headlight) leaking thru the seal on the actuator rod. Look for the "ribbed" boot on the head light motor rod and see if it looks "collapse". If the inner seal is in good condition, there should be no vacuum inside the boot.
 

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B.C. said:
have all new hoses except those under dash, everything
works but system will not hold vacuum. i understand that
it should hold vacuum enough to make lights open at least
once after motor is shut down!!!!
See my post #5 above on this thread. Yours is a classic symptom of a bad check valve.
 

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Discussion Starter · #9 ·
Since both headlights and wiper door are showing symptoms, I suspect your vacuum system check valve.

Easy to check. Remove it from your system and blow into the single large port (the other side has two ports - one large and one small). If you can blow through the valve in this manner, it is bad and must be replaced.

A bad check valve lets your vacuum escape when you open the throttle OR when you shut down your motor. And since both headlight and wiper door systems are "fail safe", they will tend to open or fail to close when you loose vacuum.
I could blow strait through it! (quick call to Vol Vette) :thumbsup:
 

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Discussion Starter · #10 ·
:agree:

Sometimes the outsides of the vacuum lines look good but the inside is dry and cracked. The way I ensure a good fit, on ALL connections with old hose, is to pull the hose and trim about 1/4" off the end then slip it back into the nipple.

Typically this will buy more time before the lines have to be replaced, and after trimming they seal a lot better. Might solve your problem.

If not, it might be a defective relay.
Trimmed!:thumbsup:
 

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Discussion Starter · #12 ·
I'll update when I get my check valve.:cheers:
 
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