I just recently bought a '75 Vette and know very little about them apart from the fact that they are beautiful. I am restoring it and have begun to work with the headlights because they are very slow to open and one does not close well. I speculate that there may be a tear or a leak on the vacuum seal that may be retarding the opening of the light. Do you have any ideas of what I can do to troubleshoot this problem? I do not know whether the closing of the lights is related to this problem. However, there is an elecrical plug that is connected to the pivoting joint on the headlight on the light that will not close that is torn off from where the one on the other side is. Does this electrical component trigger the light to close? I greatly appreciate any input that any of you may have. Thank you!
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Re: '75 Corvette Headlights
Stephen----
The very first thing I would recommend for you to do is to replace the headlight vacuum actuator seals. The vast majority of the time, if the actuators are a problem, replacing this seal will correct it. These seals were never available from GM as a service part, but most of the Corvette supply houses sell them for about $10 each. Very easy to install, too. Beyond that, there are a myriad of possible problem sources which are far too detailed for me to get involved with here.
The electrical switch that you are probably describing is the switch which activates the "headlamp open" light on the center console. There are 2 of these switches, one on each headlamp. This switch, GM # 3951239, has been discontinued but I believe that they are available in reproduction.In Appreciation of John Hinckley -
Re: '75 Corvette Headlights
Attn Joe Lucia, Can you get seals for 1971 wiper door actuators also. If possible can you tell me a supplier? Thanks in advance. Paul Young #5962Comment
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Re: '75 Corvette Headlights
First of all listen to Joe L. he has corvette juice in veins. Joe has helped many times over the past 10 months. We bought a 1970 LS5 vette and his advice has been invaluable. I had a similar problem, and I checked the actuator with a hand held vacuum pump, they were good. (They were probably replaced already) Next, instead of trying to spend millions of hours looking for a leak, I purchased a complete set of molded hoses from dr. rebuild. With 4-5 hours and a couple bruised knuckles I managed to replace all of them. One warning however, the vacuum bypass switches under the steering column were old and brittle. Needles to say but I broke the nipples off. The good news is that GM dealers still stock them for $14. Another observation was that a majority of the hoses were loose at the fittings, loose fittings=leaks. Also as a footnote I started at the front RH head light and worked my way back to inside of the car. I also changed the check valve. If you have any questions please feel free to email me.
All is well, and on to the next project.Comment
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Re: '75 Corvette Headlights
Paul----
Yes, the seal on a '71 wiper door actuator can be replaced and is available, although it was never available from GM as a SERVICE part. Most of the Corvette supply houses have it. Corvette Central carries it under their part number 653156 for $10. Dr. Rebuild has it under their number 1014670. This is the seal for the "dual pie-pan" shaped actuator used from late 69 thru 72. The "cylindrical" actuator, used from 68 through late 69, does NOT have a seal available as far as I know.In Appreciation of John HinckleyComment
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Re: '75 Corvette Headlights
You've gotten solid, specific advice from Joe. Let me add, Steven, that it's time to make a corrolary investment in building a support library for your classic Corvette. I suggest:
(1) The NCRS Judging Guide (what's what and what do judges look for?) (2) The Chevrolet Chassis Service Manual (what did GM tell dealer
repair techs about care and feeding?). (3) The NCRS Operations/Performance Verification Manual (how should
things work?). (4) The GM Assembly Information Manual (how did the guys at St. Louis
originally put the car together?). (5) Load up on catalogs from quality reproduction parts houses to find
what's available (Corvette Central, Dr. Rebuild, Paragon, Mid
America, and Zip Products make a nice starting point for your Shark).
Next, there's a theory/diagnostic book available from many of the catalog houses on trouble shooting Shark headlight/wiper door vacuum systems. It's also in the NCRS Library as are the first four items and as an NCRS member you can get the publications at a discount. Knowing who does (supposed to do) what/when/where really helps tackle this maintenance chore.
Last, I've had several Chapter members take the approach of 'gutting' the rubber hose system without complete satisfaction. I've also had Chapter members I advised to 'blow' an afternoon working through what they've got, cleaning up the factory original rubber and preserve its originality that were completely happy with the results. Depends on what you want to do with the car....
But, don't overlook some 'simple' stuff. Like, if there's a leak in your vacuum system (pretty common) there's probably more than one point of rupture so track and kill 'em all! Then, if you've had a leak, think the system's been open to airborne 'crud' (that's a high tech term) and it's worked it's way inside.
Designers originally installed an in-line filter (cheap $4 part still available from AC Delco) at the intake manifold source. This part had a service life, but few bother to replace it. If your system's been leaking, odds are REAL GOOD the internal screen in the filter is plugged and it should be replaced. If you don't replace it (I do mine every other year on my '71 driver):
(1) You're going to suck the filter screen into your intake manifold. (2) You're not going to have the dynamic airflow characteristics the
designers intended (race conditions along different paths of the
vac system under start-up, accel, decel and 'funnies' like winking
headlights Etc.)
Enjoy your car!!!Comment
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