'75 model. My manual doesn't give instructions or vacuum values for
troubleshooting a sluggish headlight system. Right light is sluggish when
it works and the left light needs human assist for any up/down movement. It
does say that defective vacuum actuators can be removed thru the hole
created by removing decorative front grill. I don't see how the things can
get past the large tubular vacuum tank. I hope I don't have to remove the
hood to replace those items. TIA
I don't have first-hand knowledge, but I do know there's a book on the
subject; here's links to a couple of articles, one of which references
Thanks for the links. The first link talks about the general idea that
vacuum systems fail over time; the second link is an advertisement for a
book on vacuum systems; and the third link talks about repairing the vacuum
system that operates wiper doors on a '72. I couldn't access info on
revamping vacuum operated headlights that was a feature article in the Feb.
03 issue of Vette magazine, the link info. source. If you have a
subscription would you mind sending along a link for that issue ? TIA.
Should be pretty much the same as your system, I think.
I do have a subscription, and that issue, but I don't understand how
that would enable me to give you a web link to part II of the article...
I couldn't find that installment on their website, either.
In part II they chose to replace every part that Mid America carries
(including both sets of actuator relays and actuators, and all linkage
springs), but recommend the troubleshooting book (The Vacuum System
Troubleshooting Guide by Frank C. Prow, also available through Mid
America), and a vacuum gauge, to determine the specific parts you need.
I have a 76 that had sort of the same problem. Left side was much slower
than right side.
Replace the main vacuum line going from the reserve tank up to the check
valve, it has probably weakened after 30 years ($0.25/foot at most auto
stores). Replace the check valve and the filter near the engine (you can
temporarily remove and bypass the filter with a single vacuum hose until the
new filter arrives). Before you assume that you need to replace the
actuators and valves, do what I did. Squirt the boot seals on the acutators
with WD-40. Remove the valves and blow them out (carefully) with compressed
air and WD-40 them too.
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