common problem

[ft laud mike]

Well it happened again. Drove the vette to work (night shift). had no problems with lights on the way to work. in the a.m. it was raining so, no problem turn on wipers- nothing, no movement sound anything... headlights still worked(went up). when i got home one headlight did not retract. Im thinknig it may be a hose which came loose?... i did not hear any hissing or noise.. any thoughts
thanks
mike

[wishuwerehere82]

Mike,

Take a look at your pivot points on the headlamp assembly. A little grease might help the lights to go up and down at little easier. If that doesn't work, then the actuator might have pinhole on one side of the diaphram. The diaphram is in the middle of the actuator and moves back and forth depending on which side you apply vacuum to. If one side is rusted, then it will only go one way.

[ft laud mike]

does the actuator in the front control the wiper door as well? Ive looked at some diagrams but cant make heads or tails of what goes where
thanks
mike

[wishuwerehere82]

The wiper door has it's own actuator on the firewall, but they use the same vacuum accumulator in the front. Just start tracing vacuum hoses from the manifold to the accumulator and back to the dashboard controls and the actuators to keep it simple.

[VBP]

If you need to replace any of the vacuum hoses or mechanical parts on those systems, check out this website I saw in another thread:


Dr. Rebuild: http://www.docrebuild.com/dr-r-web/aaa-home.html

Looks like they have just about all that kind of stuff there...

Sincerely,

Alan G.
Vette Brakes & Products, Inc.
http://www.VBandP.com

[srs244]

i can vouch for doc rebuild's vacuum kits. they are accurately reproduced, sized properly both as to length and diameter (which some of the "cheapy" kits are not, making installation in the vacuum relays where 3 lines are right on top of one another almost impossible), and contain all the necessary parts (hoses and "t" connectors). their kits aslo include a step by step color coded "wiring" diagram making replacement very simple. double check to make sure that one of the hose ends hasn't worked itself loose first however. at around $45.00 + the kits aren't a cheap fix if the problem turns out to be something else. there are so many different pieces of the system (particularly those years where the wiper door is vacuum operated also) that need to be completely sealed to provided appropriate vacuum that it is easy to become "disoriented" in diagnosing the problem. try to listen closely for a hiss if possible. it will make the whole problem easier to take care of.

steve

[srs244]

Originally Posted by wishuwerehere82

The wiper door has it's own actuator on the firewall, but they use the same vacuum accumulator in the front. Just start tracing vacuum hoses from the manifold to the accumulator and back to the dashboard controls and the actuators to keep it simple.

i think the vacuum tank on the 70 vette is mounted inside the driver's side fender just in front of the master cylinder area. it was changed to a "log" type tank mounted in front of the radiator for the 73 model year (i think 73 was the first year for it). the wiper system has it's own actuator AND it's own vacuum relay valve which is identical to the vacuum relay valve mounted between the headlight actuators up front. if you have an assembly manual, you should be able to find the vacuum line routing diagram and should be able to trace it out. perhaps someone can comment on whether the wiper system uses the same vacuum feed off the manifold, or a seperate one from the headlights, i'm not certain of that. the fact that one headlight "hung up" open is probably more a lubrication problem than anything else. as an emergency feature, you can reach under the front end and lift the headlights open. when you do that, they "lock" into place and you need to go back up under the front to relieve the pressure on the clevis pin bracket to get the light assembly to fold back down. without vacuum, they shouldn't stay "up", so i would apply some white lithium grease to the assembly to lube it up.

[ft laud mike]

thanks aLL, I guess i know what ill be doing on my next day off. he rebuild kit from docs may be a good idea regardless of what the problem turns out to be (30+ yr old hoses dont have much life left in them)
mike