Headlight problem Diagnosed, need second opinion!

[vetteboy86]

Working on a 74, and trying to get the headlights to raise and lower properly. I installed all new springs, as the ones on were shot, and half were missing. I have verified vacuum every where it needs to be.

Neither of the lights work. So the next step, I unplugged the passenger side light's vacuum source from the controller. The drivers side raises and lowers as normal. Plug the passenger side back in and neither work. I put a vacuum pump on the passenger side actuator, and it will not lift, nor can I build any vacuum with the pump. I am thinking the actuator is bad. The controller seems to work correctly, changing vacuum sources to the actuator when vacuum is applied by the switch. Anyone have a different thought about the actuator being bad.

Thanks,
Craig

 

[6880 Mike]

...I am thinking the actuator is bad...

I agree. It might only need a seal kit, but I would think you could hear a vacuum leak if the seals were bad.

 

[vetteboy86]

Well that is what I was wondering. Also, should I hear the idle speed change once I turn the head lights on? It would be a vacuum leak?I don't know how bad the leak is, but I do know that I cannot raise that headlight with a vacuum pump, where as I can raise the other one.

 

[petes74ttop]

Here's a good link for testing the different parts of the system, the diagram is wrong at the headlight and pull down switch but the rest is good. PG. Vacuum Troubleshooting

 

[vetteboy86]

That is an excellent article. Thanks for posting. I do believe I have a bad diaphragm. When applying the vacuum pump, I can not get the headlight to raise. I am going to try to open it all the way, and see if vacuum will hold. I will post back.

It doesn't look to difficult to change them. Looks like four bolts, and the pin that connects the actuator the the actual headlight. Any tricks, or straightforward as I imagine?

Thanks again!

 

[GerryLP]

Vetteboy,

I am not sure, but I thought that the 86 headlight system was essentially a re-configured system from early C3's, so could it a shaft seal or some other kind of seal?

 

[82ColEd]

Craig,
must be bad headlight day. Linky chuckle)

Here is a Actuator Removal PDf from Willcox, that kinda made it crystal clear, how and what.. Willcox Corvette, Inc. - Parts, Restoration, Help - "When you're not the biggest, You try harder"

Hope it helps..


-Stefan

 

[vetteboy86]

Thanks for all the info. Removing actuator really isn't a big deal, at least on the 74. I would imagine your 82 might have a few more things involved!! Seems that the newer they get, the more has to be removed for a repair.

 

[jdp6000]

Only trick on the 82 is getting the actuator out. You can get at the bolts with the hood open. But when you try to manouver it into place to lift it out the hood is in the way. So you need to have someone close the hood 2/3 of the way or so and you need to move the actuator to the center where the gap is biggest then have someone slowly open the hood again. Maybe the same on a 74...

Jim

 

[82ColEd]

Thanks for all the info. Removing actuator really isn't a big deal, at least on the 74. I would imagine your 82 might have a few more things involved!! Seems that the newer they get, the more has to be removed for a repair.

Aint that the truth.. Good luck with yours!

Only trick on the 82 is getting the actuator out. You can get at the bolts with the hood open. But when you try to manouver it into place to lift it out the hood is in the way. So you need to have someone close the hood 2/3 of the way or so and you need to move the actuator to the center where the gap is biggest then have someone slowly open the hood again. Maybe the same on a 74...

Jim

Good one Jim, i'll keep that in mind for mine..


-Stefan

 

[kelly3]

i have the same problem on my 81 took it to the chevy house the right actuator was bad im going to try the seal kit my self it a lot cheaper than a new actuator

 

[vetteboy86]

I'm working on an 80. I replaced both headlight actuators, as I ruined the original ones.

http://www.corvetteactioncenter.com/forums/thread123056.html

So I have installed a new set. I tested them before I put them in as they were an ebay purchase. I used my Mity Vac pump, and was able to get them to both move in and out.

I have them installed in the car, and started with nothing. I verified all vacuum hoses to be good. I wanted to isolate the issue, and unhooked vacuum source to the drivers side light. With the vacuum source removed to the driver light and plugged, the passenger light operates correctly. If I plug drivers light in, and unplug passenger side light and plug, the drivers side light will not work. With both hooked up neither will work.

So I believe that the vacuum solenoid's (divert vacuum for up and down to each actuator) work. I can use my Mity Vac, and get the drivers side light to lift and lower.

I'm thinking towards a bad actuator seal on the drivers side, but this would contradict my ability to raise and lower via vacuum. My question is that when I pull vacuum on the actuator in either direction fully extended should it hold vacuum? Also, while moving in either direction, should it hold vacuum, or should I need to constantly pump the vacuum pump and build no vacuum as the rod moves?

 

[jdp6000]

I'm working on an 80. I replaced both headlight actuators, as I ruined the original ones.

http://www.corvetteactioncenter.com/forums/thread123056.html

So I have installed a new set. I tested them before I put them in as they were an ebay purchase. I used my Mity Vac pump, and was able to get them to both move in and out.

I have them installed in the car, and started with nothing. I verified all vacuum hoses to be good. I wanted to isolate the issue, and unhooked vacuum source to the drivers side light. With the vacuum source removed to the driver light and plugged, the passenger light operates correctly. If I plug drivers light in, and unplug passenger side light and plug, the drivers side light will not work. With both hooked up neither will work.

So I believe that the vacuum solenoid's (divert vacuum for up and down to each actuator) work. I can use my Mity Vac, and get the drivers side light to lift and lower.

I'm thinking towards a bad actuator seal on the drivers side, but this would contradict my ability to raise and lower via vacuum. My question is that when I pull vacuum on the actuator in either direction fully extended should it hold vacuum? Also, while moving in either direction, should it hold vacuum, or should I need to constantly pump the vacuum pump and build no vacuum as the rod moves?

Vaccum works only one way. This link should help.

Vacuum Troubleshooting

 

[Vettehead Mikey]

My question is that when I pull vacuum on the actuator in either direction fully extended should it hold vacuum?
Also, while moving in either direction, should it hold vacuum, or should I need to constantly pump the vacuum pump and build no vacuum as the rod moves?

Yes to both questions.

Does this car have one relay or two (I forget on an '80)

 

[6880 Mike]

...Does this car have one relay or two (I forget on an '80)...

Two, I believe; one for left and one for right.

 

[vetteboy86]

Vaccum works only one way. This link should help.

Vacuum Troubleshooting

I have seen this a few times. It is very informative I will try to utilize this with my troubleshooting. I believe my first test should be if the grommet and the diaphram are good on both actuators. From my testing, I think that with the headlights fully up, one of them doens't hold vacuum.

Yes to both questions.

Does this car have one relay or two (I forget on an '80)

Two, I believe; one for left and one for right.

Yep, it does in fact have two! Thanks for the replies.

 

[vetteboy86]

Update!!

I have restored headlight operation to the 80 I was working on. I performed the necessary checks on all systems. The headlights would still not function correctly.

I ended up finding that the fittings on the used actuators must have been smaller than the ones I removed, or the original vacuum hoses weren't correct to begin with.

Once I put clamps around the hoses everything works great.

 

[Vettehead Mikey]

Good news!

 

[HammerDown]

DARN >>> looks like I'm in this mess too!

DARN >>> looks like I'm in this mess too!

I've replaced the front cone seal on my drivers side with a new one yet > the door is still lazy to lift.

The actuator can holds vacuum no problem.

It lifts some > starts to droop, then when the passenger side is up all the way the drivers side will then fully go up.

Same thing when going down > the drivers side is slow to drop.

 

[vetteboy86]

Check your hoses, and also make sure your connections are tight. My issue was that once I knew the actuators were good, the hoses didn't fit the fittings very well.