Fuel cap sealing again

[Robbie693]

I was browsing the archives and found a thread relating to this.

Someone mentioned that the fuel was getting out through the screw in the centre of the cap seal and that they wrapped cling film over the seal to cure it...

Will cling film resist fuel vapour?

Can I use a sealant on the screw to seal it and what should I use?

[Hamish Coutts]

Robbie,

You can either use white PTFE tape (used by plumbers the world over) or blue hylomar. I used PTFE tape to seal a joint on my fuel pump and hylomar to seal the sender unit on mu new fuel tank. Both are OK.

I have unsolved trouble with a leaking fuel cap but with mine it is the seal between the large rubber washer and the filler neck - the spring is not pushing them together with enough pressure to seal them. Once I can find a suitable spring the problem will be solved.

Hamish.

[Robbie693]

Thanks Hamish, I'll try the PTFE thing

I don't know exactly what is causing the leak, just thought it was worth a try. Difficult to see where it's coming from as it only does it on the move around corners... I can't see anywhere to hang on to the outside!!

I did buy a new seal for my last Plus 2, but can't remember if it fixed the problem.

Let us know if you fix it with the spring

Cheers

Robbie

[Fubar]

I tried all sorts of things to seal my cap - new rubbers, bungs in the filler neck.. The only thing that did the trick was to scrap the original cap and fit a 'Le Mans' type from an early Mini, with the vent hole soldered up.

[Hamish Coutts]

Fubar,

Did you have to do anything to the original filler neck to fit the le Mans cap?

Hamish.

[crannyr]

For what it is worth I have cured two different Plus 2s with this problem. Clearly all the gaskets need to be fresh to include the small rubber tube sealing the retaining screw. The problem is that with wear and time the latch contact areas wear to the point that once closed the seal in either not square or under enough pressure. My solution was in one case to have a bead welded under the sealing rim and then carefully trimming to the absolutely minimum and still latch. In another case I was able to bend the sealcover where the latch engages enough to accomplih the same. Hopes this helps.

[Fubar]

Hamish,

No modification to the filler neck were neccessary - the new cap had a collar which was an interference fit to the filler neck, to which the cap assembly screwed into.

Unfortunately I can't remember where I got the cap from - may have been eBay!

[berni29]

Hi

One of the last times I drove my +2 before the head gasket went, I had half filled the tank and unbeknown to me the cap had popped open. There is a large roundabout near me and as I drove quickly round it I noticed cars behind me swerving erratically. In my rear view mirror I could bee a plume of what I first thought was water, not unlike the wake of a jet ski. Thank the lord no one was on the pavement.

I really check it now.

Berni

[DaveyBoy]

For what it's worth, I had the leaky petrol cap problem and having read the same old thread regarding cling film I gave it a crack (dismantled cap and wrapped rubber & central hole with cling film). Happy and somewhat surprised to report that I haven't had any leak since (about 8 months)