tank sender sealing

[alexblack13]

God knows! I had it sitting on the bench at the time and cleaned it down with brake cleaner..

Wellseal was the recomme'd sealant at the time too.

No worries! 10 min job with tank out and everything is free as a bird.

Al' ....

[alexblack13]

Drip drip drip again.. I will take the tank out very soon methinks.

Beginning to think it is the sender itself that is leaking. It looked to be stopped leaking until I reconnected the cables.. Hmm...

Does anyone have a rubber bung to fit the tank neck for sealing off purposes to allow a lb or two pressurisation to find the leak?

Google again?

LOL....

Alex B ...

[prezoom]

Used Hylomar Blue, original formula, 6 years ago along with the original gasket and it still sealing just fine. Does a good job on threads. Plus it will come apart easily if needed.

Rob Walker
26-4889

[types26/36]

I am surprised that you are having problems sealing the gasket as I have made gaskets previously from both cork and Vellumoid gasket paper, sealed them with Hermitite (or its equivalent) sealed the screw threads with ptfe tape and never had a problem.
If the fitting is dripping it sounds more like then just a weep from the gasket, I could be totally wrong here but I seem to recall that on the original type steel tank there is a thicker steel ring spot-welded to the inside of the tank and that what the screws screw into, I would suspect that there is a problem around the spot welding .....possibly a crack or failing that you have a defective tank unit with the petrol leaking past the gauge fitting.

[alexblack13]

Hi Brian,

Yes I am thinking similar to you. Never thought about ptfe on the screw threads but I will do so this time though.

I am going to pressure test the tank when I take it out to determine Just exactly where it is leaking and take it from there.

Cheers everybody. I will keep you posted.

Alex....

[AHM]

I think that the fuel makes the cork expand and seal property. If you coat it in sealant it won't expand.

Cork was around for a few thousand years before they invented the other stuff

Perhaps the sealant is the problem. Easy enough to try without.

The WSM. Doesn't call for any

[alexblack13]

Fair comment. I'm no sealant expert though.

It will be pressure tested for a few days before it's refitted this time. It was a NOS tank so it should not have any defects. Hopefully.

Keep you all posted.. I had hoped to get the tank out today but.. I am in the middle of a Kitchen refit and Mrs B has an eye on me..



Alex B..

[types26/36]

This tank had a slight drip although it was not from the gauge unit

[alexblack13]

That one is for the skip. It's completely fooked.

AB

[billwill]

Let me guess.... There were no drain holes in the boot ?

[types26/36]

[quote="billwill"]Let me guess.... There were no drain holes in the boot ?[/quote

No that was not the problem, the tank had rusted through from the inside. Water in the petrol through condensation I suppose, it had been repaired previously as can be seen but it was way beyond redemption and went to the local recycling centre.

[alexblack13]

Hi Guys.

I removed the tank this PM and did a quick pressure test and it was leaking past the gasket at the bottom end. Stripped off the sender and all I could see was the gasket was pressed quite thin. Nothing else to see at all. No visible faults (tank was new mind) and all threads and screws are in good nick. So it looks like a new gasket and try again. What I did notice this time was that there was not a lot of wellseal to be seen on any of the faces,so I am wondering it that time I just sealed the screw threads. I think poss' so.... This time I am going to use the threebond gasket 'stuff' (I could find it easier!) ..... And I will apply some ptfe tape to the screw threads. A little belt and braces &I will give it an overnight or two with some paraffin inside and a couple of psi pressure to check it before I fit it back in.

Keep you posted. I will sort it..

Alex....

[billwill]

The tank material is so thin on the front side (where the sender goes) that if I was getting any trouble there I would seriously consider making a new brass ring about 1/8" thick, threaded with the sender holes and then solder that ring onto the tank, to form a really, really nice mount for the sender.

[alexblack13]

Thanks Bill, There is a nice thick ring already on the inside and this is threaded to take the fasteners. it is approx 5-6 mm thick on this tank.

What I have thought about is making a ring to fit onto the sender unit to stiffen that up a bit.

I spent a little time tonight going over the tank sender mounting with a big magnifier and it does look all A1 and It is fairly flat and straight too.. So.. The new gasket will be stuck onto the (cleaned) tank with the 3bond and the sender, also carefully cleaned, will be stuck to the gasket with same. Ptfe and small fibre washers on the Fasteners then to hold the bugger in place. I will see if I can get a 'stiffener' ring onto the sender unit tomorrow and will make one if it will fit ok..

I am sure it will be fine.

Thanks again.

Al' ....

[elanner]

Alex,

Before you put everything back perhaps have a good look at the 12v connector post? I briefly looked at mine and it wasn't obvious to me how it was put together to form a petrol-proof seal. But it didn't leak, so I didn't investigate any further.

Nick