Do i have a vacuum leak on my headlamps?
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I have a 1969 +2s. The lights are the "non-failsafe" type and so retract when there's no vacuum.
With the engine running, they are a little sluggish to lift, but stay up fine. However, they retract almost immediately once the engine is stopped (when the dashboard switch is left in the "raised" position). Does that mean i have a leak in the vacuum? I expected that the lights ought to remain raised and sink slowly over a period of time? (much as the failsafe version is supposed to be able to remain down for a period of time)
Does it say in the hand book how they should behave? (i don't have a copy....)
Thanks in advance
Steve
With the engine running, they are a little sluggish to lift, but stay up fine. However, they retract almost immediately once the engine is stopped (when the dashboard switch is left in the "raised" position). Does that mean i have a leak in the vacuum? I expected that the lights ought to remain raised and sink slowly over a period of time? (much as the failsafe version is supposed to be able to remain down for a period of time)
Does it say in the hand book how they should behave? (i don't have a copy....)
Thanks in advance
Steve
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sdenny - First Gear
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I think they should go down immediately, if you have turned them off. With the lift switch on, I would expect them to stay up for a while.
The failsafes fitted to mine rise slowly due to tiny leaks in the vacuum system although the manual says they should stay down for 12-24 hours.
The failsafes fitted to mine rise slowly due to tiny leaks in the vacuum system although the manual says they should stay down for 12-24 hours.
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JonB - Coveted Fifth Gear
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I wouldn't worry about it, mine has behaved like yours for the last 47 years.
It probably does indicate an air-leak into the vacuum, probably at the dashboard valve/switch, but it doesn't matter much.
It probably does indicate an air-leak into the vacuum, probably at the dashboard valve/switch, but it doesn't matter much.
Bill Williams
36/6725 S3 Coupe OGU108E Yellow over Black.
36/6725 S3 Coupe OGU108E Yellow over Black.
- billwill
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Steve
You have a vacuum leak , could be anywhere from the inlet runners via the switch and cross member to the vacuum pods..
One step at a time isolate and test.
John
You have a vacuum leak , could be anywhere from the inlet runners via the switch and cross member to the vacuum pods..
One step at a time isolate and test.
John
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john.p.clegg - Coveted Fifth Gear
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With the engine running and the lights up, try to clamp the vacuum line in various places, probably not good to crimp the plastic line, but the sections of rubber connecting hose should be possible to crimp.
Start at the vacuum pod, they rust and can easily become porous. If ok work back towards the dashboard switch and non return valve on the manifold and hope it?s one of these otherwise it points to the front cross member vacuum tank which is the worst case! Mine used to stay up for an hour or so before I converted it to failsafe, then they stayed down for a similar time. They eventually struggled to be pulled down, and that?s when I found I needed a new chassis........
Start at the vacuum pod, they rust and can easily become porous. If ok work back towards the dashboard switch and non return valve on the manifold and hope it?s one of these otherwise it points to the front cross member vacuum tank which is the worst case! Mine used to stay up for an hour or so before I converted it to failsafe, then they stayed down for a similar time. They eventually struggled to be pulled down, and that?s when I found I needed a new chassis........
Change is inevitable, except from a vending machine!
- Bigbaldybloke
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Thanks for the advice/comments.
I'll have a look over the weekend. Thinking about it I seem to remember being able to hear "air flow" coming from the locality of the switch, so perhaps that's were to start.
I've found the diagram in the workshop manual, and now know what pipe should connect to where, but it's not obvious if the pipe connections are just interference or should be clamped some how. Any comments?
The car has been restored (not by me) but as far as I'm aware is stock. The pods were new on restoration (about 18 months ago) so hopefully it's not them. It's been a while since i looked under the car, but i seem to remember the lines looked new(ish) (but i've only really glanced at them in passing).
If it is the switch, can they be serviced/refurbished? I'm assuming you can't buy new.....
I'll have a look over the weekend. Thinking about it I seem to remember being able to hear "air flow" coming from the locality of the switch, so perhaps that's were to start.
I've found the diagram in the workshop manual, and now know what pipe should connect to where, but it's not obvious if the pipe connections are just interference or should be clamped some how. Any comments?
The car has been restored (not by me) but as far as I'm aware is stock. The pods were new on restoration (about 18 months ago) so hopefully it's not them. It's been a while since i looked under the car, but i seem to remember the lines looked new(ish) (but i've only really glanced at them in passing).
If it is the switch, can they be serviced/refurbished? I'm assuming you can't buy new.....
Last edited by sdenny on Tue Feb 06, 2018 9:37 am, edited 1 time in total.
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sdenny - First Gear
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My non failsafe on my Sprint eventually go down after 10-12 hours. But then on my failsafe plus two, they never come up with the engine turned off unless I operate the switch. Don't ask me why! I'd start with the T piece on the chassis which can work lose and work back from there. Jim
- JimE
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I had a similar, but not as bad, situation. Look here towards the end of page 2 for the resolution; lotus-chassis-f36/vacuum-pods-t34444-15.html
I think I`m right in suggesting that if you pull off the 2 tubes going to the switch and join them temporarily with some connector, you`ll see if the switch is at fault. A cracked T piece is the easiest and most likely fault to investigate.
Jim
I think I`m right in suggesting that if you pull off the 2 tubes going to the switch and join them temporarily with some connector, you`ll see if the switch is at fault. A cracked T piece is the easiest and most likely fault to investigate.
Jim
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Steve
The pipes are just a push fit,and they only go on the " switch" one way ( the other way is wrong ) , they can be overhauled but only by a qualified bodger.....
John
The pipes are just a push fit,and they only go on the " switch" one way ( the other way is wrong ) , they can be overhauled but only by a qualified bodger.....
John
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john.p.clegg - Coveted Fifth Gear
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