Fuel Tank Leak - O-Ring

[boxer]

After fitting a new fuel filter and installing a new o-ring to seal the access hatch, petrol is leaking from the filter access cover.

I had a lot of trouble sealing the cover but eventually managed it by progressively tightening the 6 nuts that retain the cover. I had to really tighten the nuts to stop the leak and to be honest I think tightening them up any more would risk stripping the thread on the studs.

Anyway, the o-ring appeared to be doing it's job so off I shot and chucked a couple more gallon in - and out it came. There was petrol pretty near pouring out the tank on the garage forecourt.

I'm off to work now so I'll strip it tomorrow and have a look. In the mean time anyone any ideas??

Thanks.

Russ.

 

[RussellAisbitt]

Don't know much about fixing the leak. But wash the engine with plenty of water as the petrol will make the silver paint on it turn a yukky yellow brown colour.

 

[Howard Millichap]

I think you must have cocked something when reassembling.

 

[the celt]

sorry to hear about your problem boxer, when you refitted the cover was the grove in cover plate aligned with the mould on the tank ?thats the only thing I can think off that would make the petrol pour out, if only one or two of the threads where stripped there should still be enought presure to hold back the petrol if o ring fitted in grove. hope every thing works out
regards
the celt

 

[Peter Marshall]

o-ring

Try putting a little bit of Vasaline on the o'ring when re- assembling, I took the cap appart the other day and found the O'ring seemed to be a bit big for the seet it sits in, when putting it back together use a little bit of vasaline and it will help it seet into position when pressing the plate down, worth a try.

 

[THE PICT]

ARALDITE!!!

 

[boxer]

Russell Wrote:

But wash the engine with plenty of water as the petrol will make the silver paint on it turn a yukky yellow brown colour.

I did, though it was more an attempt to cool things down.

Will petrol ignite on a hot exhuast???

Howard Wrote:

I think you must have cocked something when reassembling

My first thought as well, but I've had it apart about 3 times and it leaked everytime. Not the first time I've done the job as well - never leaked before.

The Celt Wrote:

when you refitted the cover was the grove in cover plate aligned with the mould on the tank ?thats the only thing I can think off that would make the petrol pour out,

As far as I'm aware everything was were it should be - I was real careful. It's about the only thing I can think of though and that's why I posted. The 6 studs should position the cover accuratley.

Peter Wrote:

Try putting a little bit of Vasaline on the o'ring when re- assembling, I took the cap appart the other day and found the O'ring seemed to be a bit big for the seet it sits in, when putting it back together use a little bit of vasaline and it will help it seet into position when pressing the plate down, worth a try.

I lubed the o-ring with Halfords rubber and nylon lubrication spray to help it slide into it's correct position. Some o-rings can swell because they have come into contact with petrol, I've read that they will return to their original size if left to dry.

The Pict Wrote:

ARALDITE!!!

You're joking? That's like a [very] last resort. No More Nails might be worth a try though.

Thanks for all your replies.

When it's resolved I'll post in case it's useful to someone else in the future.

Russ.

 

[THE PICT]

Yeh I was joking,seems your on the right track now by letting the o ring dry out.Personaly for the price of a new o ring , i would get a new one if for nothing else its peace of mind.

 

[boxer]

Yeh I was joking,seems your on the right track now by letting the o ring dry out.Personaly for the price of a new o ring , i would get a new one if for nothing else its peace of mind

"ARALDITE!!!" - Starting to look like a good idea.

It is a new o-ring. I'm going to try another one anyway.

The groove the o-ring sits in seems to have a small amount of weld splatter in it - like one tiny, tiny bit that was not a problem before.

I'll try another o'ring, wet+dry the groove and try again. The only certain thing is that it leaks. If that don't do it then may be it's coming up the studs which lie outside the o-ring.

 

[jimcg]

I have had exactly the same problem before, the O ring can be a bit of a pig to get back into the groove so check carefully before you start tightening up on the studs as it does tend to force itself out during tightening. The o ring will expand due to contact with the petrol so it is either a new one or leave the old one to dry out or several hours away from the petrol. Given the hassle of replacing it I went for a new one and was successful second time round.