Lazy lights? But not a vacuum problem.

[yandy]

Can anyone offer advice?

I have a 68+2 converted to failsafe headlamps.
The vacuum seems fine as lights stay down (as far as they go) indefinitely (really!) and all hoses, valve and switch have been recently replaced.

The lights however, are not going all the way down - although they used to. It seems the vacuum pod is not bothering about the final 3/4 inch of travel translating to the lamps remaining protruding 3 inches or so at the front edge.

I don't see any facility in the system for adjusting (short of bending the top of the actuator rod to shorten it, probably then creating problems with the lights not fully raising). Is there simply a lubrication solution - if so, what with and where? Something else known about, or is it time to start hunting for a new vacuum unit?

Thanks,

Andy

[gerrym]

Andy, I guess you have probed around and so have figured all this out by now, however:-

The stroke movement is adjusted by the rubber covered end stops, top and bottom, per each side. These can be accessed through the grill aperture or behind the light fitting (for the down position stop).

If they were correctly adjusted before, it's unlikely that thay have moved. However each screw thread (1/4" UNC?) should have a locknut to keep it in place. It's also possible that there is some foreign body jammed down in here, have a look. If all looks well in this area, check that the horizonal bar connecting the two pods, the attachment of the vacuum actuating rod to the lever, and the vacuum pod itself are all firmly attached and connected.

If that all checks out OK, you might then have to disconnect the spring and actuator and stroke the light pods by hand, to try and diagnose the problem.

Regards

Gerry

[yandy]

Thanks for the lightning fast reply Gerry.

I think though you're referring to the stops that set the resting positions of the headlamp pods themselves. These are all OK as the lamps will sit in the correct positions if the vacuum unit will take them there.

The loop at the top of the actuator rod is a very loose fit so it's possible to push the headlamp pods down to their stops by hand, without forcing the rod any further. With the engine running, the actuator rod is not following, so seems to have found the limit of its travel. The vacuum unit mounting appears to be fine and hasn't moved.

However, you mention that loop should/could be a nice tight fit to the lever. The loose fit of the loop suggests then there is room for some adjusting by bending in and downwards and improving the fit without impacting the length the rod could be extended upwards. It's not unfeasible that the loop has recently opened up. That could have occured following a previous problem with headlamps not going either all the way up or down - likely caused by freezing.

It sounds convincing, I'll give it a go.

Thanks again,

Andy

[Elanintheforest]

Check the pivot bolts (that hold the pods to the body) as well...these can partially sieze up giving the sort of problems you have.
Mark

[yandy]

Thanks Mark.

The pivot bolts are OK, and there's definitely a strong correlation between headlamp misbehaviour and sub-zero temperatures. There's been plenty of opportunity to verify that recently.

The car's been re-assembled from boxes recently so there may be moisture instead of the conventional 20 years of accumulated anti-freezing petrol vapour in the vacuum tank. I've tried to emulate this with a liberal squirt of WD40 down the hose. Of course, once one problem is solved it reveals a new one created.

Andy

[gerrym]

Andy, if you can get a little more motion by eliminating the free play from the poor fit of the actuator top loop, have you considered fitting a bush into the top loop.

Mark, in theory the pod mounting bolts (which have to swivel on the threads) should be removed periodically and greased. This should reduce friction, reduce chance of seizing and prevent damage to fibreglass. I've tried to come up with a less maintenance intensive approach replacing the pivot bolts in brass. The idea was that the combination of the brass and Mezak would be less likely to seize than rusty steel/Mezak (or zinc oxide). As brass is quite a bit weaker, I upped the size to M8 (also UNC bolts in brass are hard to come by, M8 is relatively easy). The heads of the bolts have been replaced by large flats, sort of like over-size wing nuts. I find that its a lot easier to find the hole, screw it an etc than relying on tools in a tight area. Bit like life really!

Gerry

[yandy]

I've delved a little further into this now. The wire bending didn't work and the headlights are still not coming all the way down. Two possibilities occur to me and I'd welcome any comment:

1) The vacuum pod could require some kind of lubrication or general TLC to free it up and allow it to travel the full way. Is this possible/likely? What would be the recommended method of achieving this? What useful self servicing can be done? What are the pitfalls to avoid? Does anyone know what the full stroke length of the actuator rod should be?

2) The pod could be mounted in the wrong place, thereby increasing the stroke required to rotate the tie rod sufficiently, the lateral flex required of the actuator rod (increasing friction), or pushing the limits of its short stroke. This isn't quite impossible as the failsafe pods have been retrofitted. Has anyone got a late +2 with the original failsafe system handy that can specify the exact location of the pod mounting (e.g. distance from front lip/sidewall)?

Thanks,

Andy

[yandy]

Or of course, 3) the pod is bug'd and I'm looking for a new one.

[gerrym]

Yandy, the vacuum actuator contains a folding elastomer diaphragm.(It's a cup shape, so will invert, or the sides will buckle over the length of the travel). There's no sliding contact inside the body so I'm not sure what good any lubricant would so. Depending on the elastomer grade, it would probably accelerate natural degredation. Disconnect from the headlight pod and check the stroke. It should be the same as the outside "height" of the assembled pod minus say 3/4" to allow for the internal rod end, washer etc, thickness of the pod body etc.

Regards

Gerry