S4 vacuum headlight switch, failsafe

[gjz30075]

Has anyone come up with an alternative vacuum switch? Mine simply won't hold the lights down for any length of time. I had the switch apart and strengthened the spring which holds the rubber block down and I greased the area where the block rides to no avail. The way the switch is made does not lend itself to taking apart/reassembly again.

All other vacuum points are good, ie, I loop the hard tubes that go to the switch and the lights stay down for at least a week, so it's either the connection to the switch or inside the switch, which, when pushed in, simply loops the tubes anyway. This is the switch with the micro switches attached and I not too worried about that actuation yet. I'll figure it out with whatever new vacuum switch I can use.

Or, knowing the tubes are looped when the switch is pushed, an alternative set of 'guts' to the switch would also work.
I really would like to stay with the 'oem' method, for now.

Greg Z

[collins_dan]

Greg, I have the same problem. I have taken it apart numerous times and even tried clamping the two sides together tighter, because the more you strengthen the spring action for a tight seal, the more you push the two pieces apart IIRC. I've stopped fiddling with it as I am concerned that some of the parts are getting more and more fragile with time and a lights that don't stay down for long, are better than lights that won't go down. Anxiously awaiting some brilliant solution. Dan

[gjz30075]

Dan, I'm working on a solution as we speak. You're so right about strengthening the spring and the unintended consequences. Mine will seal now with the stronger spring, a thin layer of grease and a thin piece of brass on surface that rides the U shaped piece but I simply can't get the cover to stay down. The tension is too great and the little legs are shot. I plan on making another cover, ie, the piece that is U shaped and has the four little legs and I want to make the legs longer and put a hole in each one so when assembling (hopefully for the last time), I can put a small bolt, or something, in the hole to keep the cover from being pushed back. I think we can do without the detent spring in the cover; we'll see.

Greg Z

[collins_dan]

Greg, you may remember this post of Anna's rebuild of her switch. It has a couple of good pictures.

elan-f15/vacuum-switch-t13457.html

Although it doesn't show the electrical switch that rides on top and prevents easy methods of tightening the two main body parts together.

Good Luck, Dan

[billwill]

While watching TV the other day about "How it Works" I realised that one industry that uses low pressure air valves of this type is the Church Organ construction companies.

So If anyone has access to anyone in that industry, it might be worth asking what is available. My first thoughts are that they might be similar to those valves used as organ stops.

Mine is OK, but if it failed I might build one by drillings in a block of perspex. A central cylindrical chamber and a circular plunger using O-rings as seals. The plunger would be somewhat similar to the plunger of a hypodermic syringe.

[prezoom]

I had a leaking/failing vacuum switch on my S2 non-failsaif headlights. Vacuum is vacuum, so this may help.

One of the key areas of the vacuum switch, is the interior surface where the tubes are attached. This area on my switch was not completely flat, and the rubber block, being as old as it is, is not as flexible/soft as was when it was new.

The first thing I did was draw file the surface to make it as flat as I possibly could. I was surprised at just how un-flat it was. A light sanding of the bottom of the rubber block took care of any cupping. The bent flat spring needed more pressure to make a good seal, so I cut a small piece of rubber from some flat stock, and placed it under the bend of the spring. A piece of an appropriate sized "O" ring would work as well. A little rubber grease, and then assembled the parts.

As far as the additional pressure the little piece rubber provided, I created some strapping to help hold the switch together. It was apparent that my hamfisteness, when taking the switch apart, created enough damage to the four tabs that originally held the switch together, that they needed a little help with the additional internal pressure.

The end result is, after shutting the engine off, with the light pods raised, they continue to stay full up for several days. Good enough for me.

Rob Walker
24-4889

[collins_dan]

Rob, I would love to see a picture or description of your strapping solution, as that has been the problem for me. On the S4, there is a switching mechanism that turns on the lights when you pull out the knob, which makes strapping everything together quite tricky. Not sure if the S2 has a similar obstacle to work around. Cheers, Dan

[prezoom]

I took four small strips of thin metal, actually cut them out of some 18 gauge metal, drilled holes at the outer ends, just far enough apart to clear the width of the switch. Then used some number 6 screws and nuts. Nothing elegant, and thankfully it is pretty well hidden under the dash. Actually, a couple of turns of safety wire would do the job.

The original tabs were pretty much knackered up and I was not sure they would keep everything together. The original thread of the disassembly of the switch, sent me on quest to make my pods stay up longer. Long pulls up grades would cause the pods to droop.

Rob Walker
26-4889

[jeff jackson]

Hi All,
I found and fitted a perfect replacement for my old vacuum switch, I did post my finding some time back, but here it is for you all again. Just ro re-iterate I have no connection with this company, only that I am really pleased with the switch.
elan-plus-f13/failsafe-vacuum-headlight-system-t21056.html

Kind regards
Jeff 72+2

[gjz30075]

Thanks Jeff. I'm looking at something similar here in the US. A link sent to me by a good friend who fitted it (surprised he didn't post it here; he has much to offer)
http://www.ebay.com/itm/300697883136?ss ... 1423.l2649

Greg Z

[billwill]

Those look useful Jeff & Greg, but perhaps you have not realised that in the 2-seat Elan, the vacuum pods are not controlled electrically, the so called headlight lift switch is actually the vacuum valve itself, mounted on the dashboard.

It would be possible to convert to an electrically operated valve of course if a suitable substitute electrical switch can be found. It needs to match the Windscreen Wiper control in the symmetrically opposite place on the dashboard.

[gjz30075]

I understand that Bill. All either valve does, electrical or manual, is control the 'flow' of vacuum. The valve I linked to is small enough to fit behind the dash and the power can be controlled by the oem switch, which, on a later car, also controls the microswitches for the headlights, from which I can tap for power.

Greg Z

[Dennis 45/9760]

Greg, thanks for reminding me that I did not post this. (I forgot my login details so I PM you).

My solution was this: http://www.ebay.com/itm/1-4-Electric-Solenoid-Valve-3-WAY-12-V-DC-B30V-/300697883136?_trksid=p5197.m1992&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D14134%26meid%3D4952666219498626628%26pid%3D100015%26prg%3D1085%26rk%3D1%26sd%3D300697883136%26

I used one of the unused contacts on the headlamp microswitch. I don't recall all the details of how I plumbed and wired it but;

1) it is failsafe,
2) on my car, the pods stay down for almost a week,
3) it all stows aft of the heater so the "plumbing" all looks original.

The solenoid valve is a three port valve which is needed in this application.

If I recall, in one position the valve completes the vacuum circuit to hold the pods down, in the other position the valve vents the headlamp side (so the springs pull up the pods) and simultaneously closes the engine vacuum source (so you do not have an engine vacuum leak).

Right now, the car is out at the airport in winter storage. It may be a week or two until I get out there again.

When I do I will remove the driver side knee panel and gain access to the lower dash area to see how I did it. I do recall packaging the valve (which is pretty small) in padding and tucking it below the ash tray between the headlamp switch (which appears to be fully functional) and the cigar lighter. It just rests on the tunnel, aft of the heater box. The factory black plastic tubing is used. No external sign of a modification and equally important . . . IT WORKS!

[Jeff@Jae]

If the vacuum switch is beyond hope you can use the strictly electrical switch (MGA/Austin Healey etc) that will except the Elan knob to operate a vacuum solenoid up front (like those pictured for use in a +2 and solve the problem. We use a Moss Motors 140-500 (they are two blocks away) and a solenoid we get from McMaster-Carr. Works great and the facia looks original.

[gjz30075]

Update: I've abandoned the electrical solenoid idea for various reasons, although I know it works well for others. Instead, I found that a '68 to 82 Corvette headlight vacuum switch works perfectly. They're incredibly cheap on ebay at $13.00 used to about $20.00 new. Same size as the oem switch and ideally, looks like they can be mounted somehow inside the oem box, as the push/pull arrangement is the same as ours, ie, push in to hold vacuum, pull out to release vacuum.

I'm not yet ready to make irreversible changes to the oem switch to mount this switch inside so I made a stiffening plate of sorts and mounted it to the steering column to be discreet. I'll probably paint the bracket black for further discreet'ness.