Lotus Elan

Leaking gearbox drain plug

PostPost by: TroonSprint » Tue Aug 12, 2014 2:47 pm

How can i stop a drip from the drain plug of my Elan gearbox (4-speed)? I have tried PTFE plumbers tape and also Wellseal, but to no avail. It isn't much of a leak, perhaps one or two drips a day, but it's annoying.

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PostPost by: lotusfan » Tue Aug 12, 2014 3:25 pm

Before I read your post I mentally said use PTFE tape but you have tried that and Wellseal.

Are you certain it is the drain plug which is leaking? It is the lowest point of the gearbox. Could it be the filler plug leaking and running down to the drain plug? or worse, could it be the one bell housing to gearbox bolt that needs sealant?

Presumably your box is full of oil which makes it a difficult problem. Have you tried a long extension bar to really tighten the plug?
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PostPost by: types26/36 » Tue Aug 12, 2014 4:00 pm

If PTFE tape does not stop the leak I think you may have a problem with the gearbox case, it is a tapered plug so maybe someone has tightened it up so much that it has split the casing (small crack?) if not then as in the previous post I think the oil is coming from somewhere else?
I suppose there could be a problem with the plug (although I think that is unlikely) and as I recall the filler plug is the same you could try swaping them over :roll:
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PostPost by: TroonSprint » Tue Aug 12, 2014 5:38 pm

Thanks for your thoughts. The gearbox has just been rebuilt and the car is still under construction so the gear case is absolutely clean and I can categorically say that the drip comes from the plug and not from higher up. It's a bugger because it is full of new Redline oil. However, I shall drain it into a clean container and inspect the casing to make sure it isn't cracked, but I'm pretty sure it isn't. Maybe I'll try swapping the fill and drain plugs and use some more PTFE tape.

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PostPost by: types26/36 » Tue Aug 12, 2014 6:05 pm

Because it is a tapered plug and if there is a crack it may not be to visible with the plug out as tightening the tapered plug would tend to "open" the crack due to the action of the taper forcing the crack apart, you could try loosening the plug slightly to see if it makes a difference to the leak.
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PostPost by: prezoom » Tue Aug 12, 2014 7:34 pm

I like Hylomar for sealing threads. Have used it on just about every place where there are bolts, screws and plugs backed up by a liquid. After almost 8 years, none of those places are leaking. From oil to grease to gasoline (the screws that hold the fuel level sender to the fuel tank) it seems to work quite well.

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PostPost by: 7skypilot » Wed Aug 13, 2014 7:47 pm

I'd also endorse prezoom's recommendation of Hylomar. It may be an old-school sealant, but it seems to work every time.
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PostPost by: SF69Elan » Thu Aug 14, 2014 4:38 am

Hi - regarding Hylomar, are you referring to hylomar blue, or perhaps another one of the sealant products that they offer? I've just used permatex variants in the past with varying degrees of success, but am interested in what has worked for you.

Thanks!
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PostPost by: 7skypilot » Thu Aug 14, 2014 8:58 am

Hylomar Blue is the stuff.
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PostPost by: SF69Elan » Thu Aug 14, 2014 3:25 pm

Cool, thanks very much for the confirmation.

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71 Cadillac Eldorado Conv. (8.2L)
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