Headlights won't open

[Vettehead Mikey]

I didn't know that if the headlights stayed down meant you had vacuum.

It doesn't. The headlights will stay in either position quite well without vacuum - otherwise they would rise by themselves sometime after the engine is shut off. The sytem is designed to 'freeze' the lights in their last position should there be a loss of vacuum. Many papers I've seen in print erroneously state that the system is designed to raise the headlights in the case of failure, this is not true.

You only need vacuum to move the lights from one position to another. This means that you need a tight, virtually leak free system and all components functioning correctly. This applies to both the extending and retracting side of the system.

The actuator and locking system is not all that different from an aircraft landing gear mechanism, excepting that most modern aircraft use hydraulics rather than pneumatics. It wouldn't surpise me to learn that GM used this as inspiration for their design.

 

[craig32]

OK, here's the latest from Central PA. . . I got a vacuum pump and put on the side with the replaced actuator and it pumped all the way up. I tried on the other side and it only came up half way. Assumption is the actuator is shot. I pluged the hose to it and the other side worked like it is supposed to. Apparently, just like the power locks system, EVERYTHING has to work or nothing does. I took off the other actuator - after much wrestling with the clevis pin. After I got it out, I promptly twisted the end of the rod in the clevis, so much for them coming off 'easily'. I have another actuator to put on, although it is for the other side, so I will need a longer piece of hose. And of course I need to drill out the broken stud from the clevis. Good news is - I apparently have it solved, and anything that doesn't play ball will get replaced at Carlisle on Sunday. So apparently the GM mechanic was right about the actuators, but was wrong on how the hoses went on and nothing was missing, as he said. Should be done with it by Monday - finally! Thanks to all.

Craig

 

[TWINRAY]

They close fine but won't open.This is on my 82.Any sugestions on what I need to replace?At first my driver side was slow but did go up now both won't opern at all.

You can always do what I did back in 1974 on my '69. Sorry, just had to do that

 

[craig32]

You can always do what I did back in 1974 on my '69. Sorry, just had to do that

DAMN! All things considered, the vacuum system wasn't THAT hard to figure out. I dig the look of those rhombus shaped lights poppin up out of the body - I got them working. . .

Craig

 

[kiwi vet]

I've put on my fire proof long johns...so here goes!!!

Vettehead Mikey...QuoteThe actuator and locking system is not all that different from an aircraft landing gear mechanism, excepting that most modern aircraft use hydraulics rather than pneumatics. It wouldn't surpise me to learn that GM used this as inspiration for their design.[/QUOTE]

Thats Bloody Great!!!!! A very inspirational & comforting thought for the next time you get on any flight and are coming in to land at some airport!!!, Imagine the scenario (1) Pilot lowers the landing gear, (2) 1 minute later one side comes half way down, (3) then a while later the other side comes down fully - this is not good!. :ugh (4) Pilot is very concerned, in a last ditch effort after trying this exercise 2 - 3 times, but before the impact , he posts a thread to CAC on the cockpit laptop (as vettes vacuum system and aircraft landing gear system is apparently identical - or so he has heard), (5) Replies flood in from very helpful and knowledgable CAC members, Check the actuators! check the hoses! check the switch! Actually the problem could be the wiper relay as everything affects the operation of everything else! (5) Pilot overloads with the barrage of information :W and has mental breakdown or just gives up and jumps, and on his descent, vows to become a C3 corvette owner ....because when this happens again, AND IT WILL!!! he will then be able to accept this as .............NORMAL!!!!!!!!!!

Sorry, I couldnt help myself.....

 

[Alan76]

My problem is the headlight won't go down after they slowly!!! come up

 

[jdp6000]

Probably the seal at the front of the actuator. Cheap to replace and easy to fix. Make sure first the line coming from the engine intake (near rear drivers side of motor) is okay.

Test the actuators. Remove one hose at the time from the valve (located center front, when hood is open). Suck or blow on the hose you should feel resistance. One action or the other will make them go up or down. If there is no resistance when sucking or blowing....i.e. like an opened ended straw....the seal is gone.

Jim

 

[craig32]

Test the actuators. Remove one hose at the time from the valve (located center front, when hood is open). Suck or blow on the hose you should feel resistance. One action or the other will make them go up or down. If there is no resistance when sucking or blowing....i.e. like an opened ended straw....the seal is gone.

Jim

Jim,
I do not agree with this. I tried that and they both worked. You need a vacuum pump to test the actuators. I tested mine that way and one would not pump up. If both are not good, neither one will come up.

Alan76,
Did you try all the tests that Vmrod posted here? Make sure the switch and override are plumbed correctly and test the relays. Keep us posted.
Craig

 

[jdp6000]

Ahhh...primative but it worked for me. The actuators are fairly basic. Not much can go wrong with them. 2 chambers, one internal seal and one external. Its usually the front seal that goes (magicians hat as its know). I blew nothing but air came out the other side. I ordered the new seals from Ecklers (about 7 bucks each) spent about an hour taking out the actuators (which apparently you don't have to do) and my problem was fixed.

FWIW if the internal one is gone...time for a new actuator.

I should have added....the blowing and sucking on those lines simulates what the system should do. One action will make the lights go up the other down. If you have good resistance in the actuators the problem is elsewhere. Keep in mind my technique will not tell you if you have a very minor seal problem. BUT if its minor your lights will still go up and down just not as fast.

Jim

 

[jdp6000]

This kit will solve 90% of the problems with lazy headlights...

http://www.ecklers.com/product.asp?pf_id=43857&dept_id=1475&mscssid=0UCG3EFQ247F8PGNDGBMJFBK8BV32G08

 

[Alan76]

Found left relay to be bad, just bought them a couple of years ago they were after market so i guess I am not suprised. I teeed in to the right relay to run both while I wait for a new one. The early 1969's were routed this way,. I guess G.M. put two on as a safety measure so if the relay went bad you would still have one side that worked. good luck with yours


Alan

 

[srs244]

alan
actually the fact that you can reach up under the front grills and push each housing up manually if necessary is the safety feature gm built into the vacuum system, lol. not pretty, but it does work when the lights (and/or the vacuum system) take a dump while you're out on the road, lol!!

housings can be lowered in much the same fashion by reaching up and pulling downward on the cover door adjustment screw to "break" the linkage elbow and allow the housing to lower. once again, not pretty, but it does work when needed.

steve