I understand the source is usually a vacuum leak in the headlight door actuator, and for this I can purchase a rebuilt actuator from WCCC for $130 and hope this solves the problem for a long time.
Actually there are several areas that can be the source of the vacuum leak. Often the check valve will fail and let the vacuum leak back to the engine. Remove and test the check valve, it is found just past the vacuum manifold on the fire wall. The hoses may have gotten hard at the ends and may cause a leak. For this trim off about a half inch and reconnect. The headlight switch can also be leaking, if it is you will usually hear the leak from the drivers seat. Then check the vacuum storage Reservoir under the driver’s fender in front of the tire. Check everything before replacing parts, you may be surprised by what you find. Good luck with this.
Even after replacing everything, I was discouraged to see my cat with eyes wide open after sitting all week. So here is a fix that will keep the eyelids closed even without vacuum, yet let them operate normally when vacuum is present.
For me, troubleshooting and fixing all those odd problems is part of the fun. But sounds like the electric conversion may be the better option for you. Definitely not a cheap hobby, though!
I wouldn’t say perennial, since I fixed my problems and My headlights stay closed all winter, and all my heater controls work correctly. Mighty-vac gets passed around quite a bit once people find out you have one
I converted to the electric kit. The biggest pro is that they stay up, and they stay down. No more lazy eye, no more headlights glaring at me when I don’t visit her for a few days, etc.
Cons are that it isn’t original, so you’re going into hard to reverse territory if you do want to show, they slam up and down like the guillotine during the Reign of Terror, and wiring can be tweaky and cause them to double cycle (close and open again rapidly) when using the dimmer switch.
I’m used to it now, so I don’t mind the slamming noises and I never plan to show the car since I kind of do whatever I want and like the original look, but definitely enjoy some modern conveniences.
The photo tells me what I would do, and that is go electric so that gorgeous grill looks right. Other opinions and your preferences may vary. Pretty car by the way!
To each his own of course. I have a 70 XR7 also in your color. Had it since new. Added a check valve from WCCC, trimmed the vacuum hoses by 1/2 inch each, and replaced the actuator plunger seal myself, all about 10 years ago. Not much work. Otherwise original and works fine for a few days of car not running, as it did when brand new. But I can see electrical if you don’t care about being original.
I went over it with the mechanic yesterday. He’s gonna test the vacuum at the actuator inlet, and if it holds that will isolate the vacuum leak to the actuator, which can be replaced.
That’ll be the best.
If we have to chase vacuum leaks all throughout the system, that might be a reason to go electric.
There are actually two actuator ports to test - one on bottom to open the doors and one on top to close them. If the bottom port leaks, you have a leaky bellows and the actuator will need replaced. If the bottom holds vacuum, but the top one leaks, you can usually just replace the actuator shaft seal to fix that. And don’t forget to trim 1/2" from the vacuum line ends.
Make sure you have reasonable expectations. Do they come up within a few hours, or does it take a few days?
I believe Ford’s test spec called for at least 48 hours.
Mine was coming up quickly. It was a seal on the shaft, and it was an active vacuum leak which showed up in the idle quality between lights on and off.
Unfortunately, I broke one of the studs removing the actuator.
Diagnose the real problem before loading the parts cannon.
As for fixing or converting, the factory system worked pretty good. I’d rather replace a part or two than make modifications. I guess I’m just lazy that way. I prefer to call it “efficient”.
I still have an original functioning system. I trimmed all hose lengths years ago and used vaseline on each end. When my headlight doors stay up/open early I have reapplied vaseline to the hoses in/out of the vacuum canister. So far so good.
That typed, I have back up hosed and assembled an electric system for when the day comes. This is far cheaper than any kit out there.
I’m on a mission to make the troubleshooting on my car easier, which means getting rid of the 1000 vacuum lines. My next two replacements are the vacuum headlights and then a vintage air system. Already ditched the power brakes after my T5 swap and I’ll be free of vacuum forever! I do like the idea of no vacuum lines for a cleaner engine bay and under dash as well.
