Can't get fuel cap to seal

[swinny]

Bastard thing 😆  tried a new cap to no avail though I couldn't find a quality genuine one for sale... so maybe its still the cap. I do know the cap of a gx 390 fit well.... anyhow got to site and top of tank wet just from it sloshing around and being 3/4 tank full...

[spudulike]

Had similar problems with MS660 tanks.

Try the wet and dry on a flat plate of metal and ensure the mating surface is flat and not deformed by rubbing lightly.

You could use a bit of "engineering blue" on it to see what the surfaces are doing under compression.

You could inspect the innards of the tank neck and make sure they are not deformed or damaged.

You could try cutting another seal out of something like EPDM and placing it UNDER the existing one.

Failing that, chuck a match in the tank and claim on the insurance

It shouldn't be rocket science and can imagine a lot of swearing and laughing once you find the issue!!

 

[swinny]

10 minutes ago, spudulike said:

Had similar problems with MS660 tanks.

Try the wet and dry on a flat plate of metal and ensure the mating surface is flat and not deformed by rubbing lightly.

You could use a bit of "engineering blue" on it to see what the surfaces are doing under compression.

You could inspect the innards of the tank neck and make sure they are not deformed or damaged.

You could try cutting another seal out of something like EPDM and placing it UNDER the existing one.

Failing that, chuck a match in the tank and claim on the insurance

It shouldn't be rocket science and can imagine a lot of swearing and laughing once you find the issue!!

 

Definitely feel a right spanner for not sorting it yet lol 😆 but it's been low down on priorities if not been used. 

 

Wet and dry top of tank is next step I think like you say! 

 

Ahh and yes engineers blue. Forgot about that stuff. 

 

One day I may get to the bottom of it but for the other day a glove and zip tie had to do lol 😆 😅 

Edited September 18, 2023 by swinny

[swinny]

Wet and dry tank top and used the better fuel cap on the right. Still leaked 😆 🤣 

[spudulike]

Is it coming out of the breather rather than past the seal? There is a small area on the tank lip that looks a little low but the give in the seal should accommodate that. Will have to check the cap on my chipper to see how the breather functions.

You could try swapping seals around on different caps of just pick the tightest cap and use the thickest seal on it.

Looks like one of those problems where it really can't be that difficult but it is.

[spudulike]

I had a look at my chipper and the cap had a hole in the inside centre and it allows the tank to breath up this hole and down the holes around the underside of the inside edge of the fuel cap surround - like the one on the right of your last pic. 

For interest, try bunging up that breather hole with something and see if it leaks - you shouldn't run it like this but it will be interesting to see if the thing still leaks with the breather bunged up.

If it doesn't, perhaps you can get a cap like this with a one way breather.....seems mad but......it is what it is!

 

[aspenarb]

Looks like one of those standard weld on filler necks Chris. Might take one of those caps that pulls down with a key.

 

https://www.dieselcaps.co.uk/3471/filler-necks-mild-steel-filler-neck-40x45x30mm-diesel-fuel-cap/8789

[swinny]

28 minutes ago, aspenarb said:

Looks like one of those standard weld on filler necks Chris. Might take one of those caps that pulls down with a key.

 

https://www.dieselcaps.co.uk/3471/filler-necks-mild-steel-filler-neck-40x45x30mm-diesel-fuel-cap/8789

Cheers Bob, will give it a whirl

[swinny]

11 hours ago, aspenarb said:

Looks like one of those standard weld on filler necks Chris. Might take one of those caps that pulls down with a key.

 

https://www.dieselcaps.co.uk/3471/filler-necks-mild-steel-filler-neck-40x45x30mm-diesel-fuel-cap/8789

I've had a look tonight at the measurements and the one in the link is smaller ..... 

 

I'm actually considering buying the female part to this and just welding on top of the tube that comes out of the tank now.... 🤔 

[woody paul]

I had problem with land rover 130 fuel cap after replacing it cause I drove over one fitted, must of tried 3. 

Then went to land rover garage I use for spares and they gave me a original one and that never leaks, they said its the breather setup in patterned ones.