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I just finished replacing the actuators on my '74. Used a vacuum tester and it seems the vacuum is good. When I turn the headlights on, they try to open, but just a bit. So I give them the old manual assist. When I park and turn the lights off, the passenger side light goes down as it should, but the driver's side doesn't, Anyone have any suggestions?
if the hoses aren't leaking and you're getting proper vaccum, the actuators must be leaking. get new seals from one of the supply houses. hardest part is removing the assemblies from the car.
The actuators are new from ZIP-corvette. So the seals shouldn't be bad. Was very careful on installing to make sure I didn't nick the boot on the piston of the unit.
it's possible that the headlights are binding, but not likely. when you say the vaccum tested ok, did you test the vaccum on the opening and closing hoses? if that is ok, the problem has to be the headlights. if that's not ok, check the vaccum relay(s). then check the control and vaccum lines to the relay. it's just a matter of working thru the system. dr. rebuild has a trouble shooting paper on the vaccum sysytem, and i'm sure willcox also has one.
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Did you replace the actuators or replace the seals?
I've posted this troubleshooting guide before www.corvette-101.com/vacuum.htm and it may help you find the problem, the text is good but the diagram is bad so use the one I posted or the one from Willcox. Our 74's have a cylinder at the front of the car not a coffee can. If you get stumped post back, at least our 74's don't have a wiper door! PG.