Plus 2 Fuel cap leaks

[miked]

Guys & Gals, I had the dreaded leak and searched the forum. An old post between Gareth and Steve has the answer with the secondary seal.

elan-archive-f16/fuel-leaks-t7327.html

I was concentrating on the big seal and in the past missed the bit about the secondary one (behind). I drilled off the rivet top to remove and get at it. Then drilled and tapped a fitted a small screw so that I could refit all together. Then I played about with a piece of soft fuel hose to make the secondary seal. I took the filler neck off and kept filling it with water (up side down) to check that I had a seal. Need to get some tension! About 1/2 to 3/8 seems to do it. Yes I know they still make new ones in Brirmingham (same manufacturer of old) but I was sick of getting my wallet out.

No fuel leaks now with ?40 worth in the tank. Jobs a good un. More MPG and no nasty streaks

PS I will cough; I was unaware that there was a seal behind the flat disc. A lot have rotted and are not even there (40 yrs etc). I saw one that had that old cotton braided fuel hose that you have on you classic Suffolk Punch. It was as hard as hell and must have been there from the manufacturer.

Can post photos if required.

Mike

[TonyJ]

Please post photos as I have the same problem of ful leaving the tank via the filler cap. I think I know what bit I need to replace but would appreciate a couple of photos to make sure I'm thinking of the right bit .

Thanks, Tony

[miked]

my cap with new screw tapped in

Secondary seal rubber

Primary seal, washer and spring etc

An old cap with rivet

Photos as requested.

Perhaps the new rubber hose is more around the 1/2 inch depth. The brown stuff is copperslip as it was a bit corroded. You do have to push a bit harder now to make it seal but you know you are pushing on the rubber hose and there aint any leaks.

[andywatts]

You may be aware that 'nearly as new' fuel caps are available from http://www.ceandess.co.uk/. They have the lockable ones, but also the original non-lockable type, but with a slightly different design of latch. I bought one because the chrome on my original has got very pitted, and I will swap the latch.

[miked]

Bumped for JonB.
Mike

[alan.barker]

I've replaced/made a seal from rubber tube in the past but imho it is also good to add the MX5 non return to be 100%.
If you get your car painted and it is not cheap you will be crying when it is destroyed by fuel leaks.
Alan

[JonB]

Sorry, I can't see the "secondary seal rubber" in the second picture... have I missed something? Oh wait a minute, it's that bush-like thing on the shaft. A piece of fuel line hose by the look of it. Presumably it enhances the spring's pressure, a nice little hack.

One thing though, does your disk have a breather hole in it? One the picture of the old riveted cap does show a little pin hole. My cap has a pin hole in going through the top (that is, visible when the cap is closed).

[alan.barker]

It's like a tube and when you close the cap it has to be compressed. After a short time it is effected by the fuel vapour and will not compress and form a seal. The first sign is fuel over the wing attacking the paint
Alan

[JonB]

Seems to me a short bit of rubber fuel pipe would be in order (as in, "resistant to petrol fumes"). If it can be fitted over the post in the lid.

[theelanman]

and doesnt foul the lock......

I ended up making a plug/bung and seal for mine as I tried in vain to get the cap to seal and stop throwing fuel over the rear wing.......

its fine as the breather pipes are over the back window........
it'll also let you know if your pipes are blocked or not installed....

[miked]

Yes, small piece of fuel hose, second photo. Secret is to experiment with a few lengths to get some cap tension. Never leaked again. Yes I think there was a pin hole but with the breather system the tank is vented mainly by that.
Mike

[Chrispy]

I didn't have any luck with this. But with the MX5 NRV my +2 is now leak free! So good not having to get by with 1/4 of fuel all the time

[alan.barker]

I didn't have any luck with this. But with the MX5 NRV my +2 is now leak free! So good not having to get by with 1/4 of fuel all the time

Spot on, the only way is the MX5 mod.
Cheap and easy and works. Just be sure to fit it correctly.
Alan

[theelanman]

as the breathers are over the rear screen.....I made a plastic 'bung' that fitted under the fuel cap
made of fuel resistant plastic.........with an 'o' ring to create a full seal.........
It just drops in and pulls out......as required

[Rich135]

Any chance of a picture of the bung, as I think I might go down that route too, seems much easier.

What type of plastic/rubber did you use?

Many thanks

Rich