Mk3 Gearbox Neutral Switch Oil Leak

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Mart UK

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I think this is the final oil leak I need to deal with. The neutral switch works fine, so I think it is appropriately adjusted. The nut locking it to the gearbox case is firm, but looks to have no washer between it and the case. Is that correct?

The brass thread and terminals of the switch are covered in oil and drip. I can't see anywhere obvious it could be coming from other than out of the gearbox and probably through the thread and up the shaft of the adjuster.

Is this common (could only see one reference to it previously)?

there a way to seal it, preferably in-situ?
I was thinking:
- loosen the lock nut and move it well up the shaft,
- a good clean / degrease,
- wind on some plumber's PTFE tape at the case end of the shaft,
- lock nut back down.
All whilst holding the main brass adjuster bolt completely still, to avoid upsetting the adjustment.
 
The nut locking it to the gearbox case is firm, but looks to have no washer between it and the case. Is that correct?

The parts diagram shows a (Dowty) sealing ring, 06.6364.
Item 50:
 
The sealing ring/washer could be there as it sits in a recess so is not all that easy to see.
 
The parts diagram shows a (Dowty) sealing ring, 06.6364.
Item 50:
Doh. That will be it. No washer on there at the moment. I checked that diagram, to make sure it was the neutral switch and missed the washer. Will have to wait to share postage with the next bit to drop off! :)
Thank you.
 
The sealing ring/washer could be there as it sits in a recess so is not all that easy to see.
You're right, it was hidden in there. Maybe it is damaged / given up. Definite oil on the threads straight after the lock nut. I loosened it to check and tightened back up. It wasn't particularly loose, but I've tightened it a touch more. Will monitor. Thanks again!
 
Why wait as they're cheaper to buy from ebay.
Postage costing more than the item offends the miser in me. It's managed 6 months and 2,500 miles. Little prospect I won't be ordering something in the next month or so!
 
I think this is the final oil leak I need to deal with. The neutral switch works fine, so I think it is appropriately adjusted. The nut locking it to the gearbox case is firm, but looks to have no washer between it and the case. Is that correct?

The brass thread and terminals of the switch are covered in oil and drip. I can't see anywhere obvious it could be coming from other than out of the gearbox and probably through the thread and up the shaft of the adjuster.

Is this common (could only see one reference to it previously)?

there a way to seal it, preferably in-situ?
I was thinking:
- loosen the lock nut and move it well up the shaft,
- a good clean / degrease,
- wind on some plumber's PTFE tape at the case end of the shaft,
- lock nut back down.
All whilst holding the main brass adjuster bolt completely still, to avoid upsetting the adjustment.
FWIW,
I installed a brand new switch from AN (through Old Britts), it was actually leaking through the body itself. The oil appeared to come from between the black plastic and the brass. Old Britts sent me a new one, but before it arrived I installed and OEM one I had in spare GB shell. Not sure if this is your issue, but I just wanted to throw it out there.
Pete
 
Postage costing more than the item offends the miser in me. It's managed 6 months and 2,500 miles. Little prospect I won't be ordering something in the next month or so!
When something like this happens I NEVER buy one item. I use it as an excuse to by a selection / set off of eBay. A few quid down and you’re sorted for years!
 
Sidestand rubbers.... a man can never have too many, in my experience :)

(or FE's favourite: Spark plugs )
 
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Postage costing more than the item offends the miser in me. It's managed 6 months and 2,500 miles. Little prospect I won't be ordering something in the next month or so!
Plenty on ebay with free postage (even for one item).
 
You're right, it was hidden in there. Maybe it is damaged / given up. Definite oil on the threads straight after the lock nut. I loosened it to check and tightened back up. It wasn't particularly loose, but I've tightened it a touch more. Will monitor. Thanks again!
Add some sealant if it continues to leak.
 
So, a little package of things will arrive from AN today, including the replacement Dowty washer. I will measure how far the switch is in the gearbox before I remove it.

Is there a knack to adjusting it correctly? Would some RTV on the threads be sensible?

Thanks.
 
On threads where it’s difficult / impossible to clean all oil residue out properly, I think any sealer is going to be ineffective on the threads. In such cases, if I want belt and braces, I’ll wrap some PTFE around the threads tightly.

PTFE should always be wrapped around the threads in a direction so that tightening won’t unravel it. And start the first few thread with your fingernail to encourage the PTFE to get into the threads and not be pushed out of the way.

But it should not need it. Sealing is taken care of by the washer in this case, not by the threads.
 
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