left headlight goes up slow

[gravismaximus]

last year i noticed that my left head light goes up a lot slower than my right so i did some testing and this is what i found. i used a hand vaccum pump and connected it to the green hose that goes to the actuator, on the right side the lights went up, but on the left it didnt, no vaccum was made at all. and also after i pumped them up i pinched off the hose and put the pump on the red hose. after pumping it would shut the headlight on the right side, of course i couldnt do it to the left, it dont go up with the pump. so i think its a problum with the actuator or the rod seal. i decided to try and presserise the actuators using shop air. now im using presser so red would make it go up and green down. i used windex for soap to see if there was a crack i would see bubbels. i shot a qick burst into the red hose and it went up and would hold there untill i let the presser out. i then pinched oof that hose and shot some into the green hose (trying to close it) nothing!!!!! i shot a littel more and i saw bubbels coming froom the boot. so heres my question.... i can use presser and make it go up , but not vaccum, and when tring to close i see bubbels if i use presser, so im thinking its a boot prob. but if it was and i had the car running like normal and turned them on wouldnt they never come up if it was a boot problum. your thoughts please.

 

[TJay]

gravismaximus, here's a like that will help you. just click on "vacuum trouble" once you are there.

http://www.corvette-101.com/

 

[srs244]

i had to rebuild my entire headlight vacuum system, and learned the following the hard way, a bad actuator will do some strange things when you try to troubleshoot the system, lol.

that said, i had a "new" actuator fail (internally) after only about 45 days. the boot and the seal were ok (and even replaced with brand new just to make certain) it was the actuator diaphram that failed. the funny thing was that once i manually raised that headlight to the up position, the other side functioned exactly as it was supposed to (raising the "bad" headlight door to the up locked position seals off the actuator and simultaneously "restores" normalcy to the system). it (the good actuator side) would go up on it's own and it would lower when the system was shut off. after reversing the lines to the actuators from the vacuum relays (just to make certain that one of them hadn't failed), and getting the same results, it was isolated to the actuator. if you see bubbles from the actuator, i would certainly check the boot and seal on that actuator, but if they appear to be ok, i wouldn't rule out the fact that the actuator may have failed internally.

the easiest way to work on the boot and seals is through the front grill (the assembly manual accepted procedure). remove the springs holding the clevis pin in place, slide out the pin and the rod and clevis can be manipulated (i suggest you remove the two vacuum lines to the actuator as it will make moving the rod backwards a bit easier). you can pull the dust boot (the soft accordian outter piece) off at that point and check out the actual seal (unfortunately if the actuator diaphram is bad, you can't see it, so if everything else checks out, it's time to buy or borrow another actuator and give it a try). the clevis (the part at the end of the rod with the hole in it) just unscrews if you need to remove it and the boot and seal can be removed at that point. if you need to replace them, i suggest using either a lot of liquid soap over the threaded end of the rod to keep the threads from ripping the seal while putting it on, or slide the seal over a straw (again using liquid soap) and sliding the straw over the rod to keep the seal end safe, then just remove the straw once the seal is in place.

i hope some of that helps you out. there was a very extensive thread a while ago about headlights and the vacuum system. if you still need some more info, perhaps a search for it will help.

steve

 

[commando57]

Next time just wrap the threads in teflon tape.

 

[HammerDown]

My drivers side is slow on the upstroke. Several months ago I did replace the passenger side actuator rod seal because of a tear in it.
Usually when a "rod seal" goes bad the "accordian" dust boot will suck-in. However this will not happen if the actual acutatior diaphram goes bad.
I'll have to check to see if it holds vacuum.