Vacuum operated headlights

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 that book:

More links to info:

Hi Wayne, 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.

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.

Hi there, 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.

Good luck, Mark