I have now installed all the vacuum parts of the Failsave in my +2S 130. When I start the engine, it takes several minutes for the lights to finally lower. After about 4 minutes they are completely down, is it normal that this takes so long?
When I switch the engine off, the lights are up again after 30 minutes at the latest. Several threads say that the vacuum should last up to 12 hours. Does this also apply if the engine has only been running for a short time, or does it have to have been running for longer beforehand?
For Testing i have no Switch in the Pipes. Vacuum Pod, Pipes, Valve are all new. So the Leak can also only be in the Reservoir.
Or is it possible, that the Engine not deilver enough Vacuum??
There is usually a one way valve in the vacuum pipe from the manifold. You have not mentioned that, so is it OK.
Or there must be some air getting in somewhere.
Although mine is an Elan without the fail safe system the lamps rise in a few seconds and will hold for a few hours.
Eric in Burnley
1967 S3SE DHC
Have you tried driving the car? I had a vacuum check valve so tight that it would only open on trailing throttle. Lights would stay down for weeks though. With no reservoir
Do the lights move freely by hand? With no vacuum they should push down against spring pressure smoothly and pop up aggressively
You don’t show the switch in your diagram. On my failsafe Sprint, I found my oem switch leaking and
couldn’t repair it so I adapted a Corvette switch and it works great, up and down,. ebay.com/itm/154652004194?e … R4Se0s-1Yw
I wanted it to look OEM so I adapted the switch to fit a Zephyr headlight switch so I can use the oem knob.
Mine go down quickly - in seconds - and then will stay down for hours when left with he engine off so it sounds like you have a leak. Do you have the separate vacuum solenoid and single ‘pull down’ unit?
Headlights should fly up.
Occurs to me now that without a switch, how are you testing?
If you are disconnecting the hose and allowing the entire system to come to atmosphere, then that might be the issue
It takes time for the reservoir to drain
With a vacuum switch properly installed, it vents only the vacuum pod, not the reservoir
So, until you get a switch try this:
run a loop up with a joint you can get at that is only going to the vacuum pod.
after the vacuum pulls the lights down, open that joint
The vacuum pod is now separate from the reservoir, and they should pop right up
Of course in this test the reservoir is also empty and the engine will rev up unless you clamp the hose off
From what you say, I would suggest that the most likely cause will be a leak in the chassis reservoir so try bypassing it.
On my car I ignore the reservoir and run the pipes directly to the vacuum pod. With this set-up the lights will stay down for weeks with the only downside is that, if they are lift in the up position, they can only be lowered once the engine is running.
Well, since the headlights are held down by vacuum and up by springs, this seems really unlikely. A 74 would not be a Federal car, so are you sure have failsafe lights? With a heavy spring and new o ring in the original check valve, and no reservoir, it took about 2 months for my lights to come completely up with new actuator, and an electric solenoid, but when I bought the car, shutting the door caused the lights to make their first grunt
I had several years where the lights would stay down completely overnight, but that is best case with new components
The most I leave my car is 5 weeks when I am abroad for my summer holiday and they haven’t budged when I get home. They are failsafe. The only time they failed was when the vacuum was breached as a result of a faulty chassis which had to be replaced. JimE.
I looked at the whole thing again yesterday. I disconnected all the pipes for the vacuum. I then pushed the pods down by hand. These should then snap back up again using spring pressure. But they don’t. So before I look for the leak in the vacuum, this mechanism has to work first.
I have discovered that screw 53 does not properly secure rod 50 to the POD. Is it correct that this rod-POD connection must be absolutely fixed?
Yes bolt 53 secures the rod to the pod and needs to be tight. The hole in the rod is larger than the diameter of the bolt to allow the two pods to be adjuster individually to get them flush with the bodywork so there needs to be a good thick washer under each bolt head so they can tightened up properly to clamp the pods to the rod otherwise they’ll just keep coming lose. Bolt 51 is of course the pivot.
Staying down weeks or months is different from ‘permanently’
I bet the large washer is missing and the hole is getting egged out. Get that connection tight and located so it will operate full up to full down. You may have to open the stops on the farside[or not] to get the travel correct on the nearside. Once the nearside is working you can adjust the farside to match
