Fuel tank sealants

[drh1965]

I'm trying to solve a fuel tank leak problem. It is a plastic tank with a slightly reinforced hole where the fuel sending unit attaches. The sending unit is just sheet metal screwed into the plastic. The screws are partially stripped and the someone put a hunk of gasket material with a ton of blue RTV sealant under it. It still leaks. The RTV silicone didn't seem to hold up well either. Also, the places where the screws went through the plastic are deformed. I was thinking that I could try to seal the existing screw holes, rotate the sender and rescrew it in to the plastic (with a new gasket). Does anyone have any advice as to what type of sealent would work in a diesel fuel environment? Will Ultra Grey work? Are there any other clever solutions to this problem?

[Terra Nova]

Originally Posted by drh1965

I'm trying to solve a fuel tank leak problem. It is a plastic tank with a slightly reinforced hole where the fuel sending unit attaches. The sending unit is just sheet metal screwed into the plastic. The screws are partially stripped and the someone put a hunk of gasket material with a ton of blue RTV sealant under it. It still leaks. The RTV silicone didn't seem to hold up well either. Also, the places where the screws went through the plastic are deformed. I was thinking that I could try to seal the existing screw holes, rotate the sender and rescrew it in to the plastic (with a new gasket). Does anyone have any advice as to what type of sealent would work in a diesel fuel environment? Will Ultra Grey work? Are there any other clever solutions to this problem?

Yo DRH,

you would be well to realize that the main problem is a faulty installation. Slopping a bunch of akumpucky around is not a solution.

A split metal ring can be fabricated as a backing/thread-plate to go inside the tank, sandwiching the plastic tank between the two metal plates, and using a neopreen/cork gasket. Sometimes doubling the number of screws helps to spread the forces more evenly, preventing deformation of the sender flange.

best, andy

[senormechanico]

Andy beat me to it. I was going to suggest the same thing. Good luck.
Steve B.

[Terra Nova]

Originally Posted by senormechanico

Andy beat me to it. I was going to suggest the same thing. Good luck.
Steve B.

Yo Steve,

great minds run in the same channel, I've heard.

best, andy

[drh1965]

Thanks guys. I had thought of trying to get a ring in there but wasn't sure how to get it through the plastic hole without making the situation worse. The split ring idea sounds good.

Thanks.

[drh1965]

I ordered ring FLS-U from WEMAUSA: Fuel Tank Senders, Gas Tank Senders, Water Tank Senders, Holding Tank Senders by WEMA USA, Inc.


How the heck am I going to hold it in place while screwing in to it from the top? Maybe extra long screws?

[senormechanico]

You could put in a couple of extra long screws, get it centered and nearly snug. Next, put in the regular screws, take out the long ones and replace them with short ones.

Steve B.

[Terra Nova]

Originally Posted by drh1965

How the heck am I going to hold it in place while screwing in to it from the top?

Yo drh,

put two tiny flathead screws, 180 degrees apart, between the mounting holes.

best, andy

[Chief Engineer]

Of course when we are SAILING we have lotsa time to figger this stuff out.

Originally Posted by senormechanico

You could put in a couple of extra long screws, get it centered and nearly snug. Next, put in the regular screws, take out the long ones and replace them with short ones.

Steve B.

Reminds me of the joke where the guy has a flat tire in front of an insane asylum

[Alan Wheeler]

Reminds me of the joke where the guy has a flat tire in front of an insane asylum

And??????........ ya can't leave us dangling like that.

[Boracay]

Flat tyre joke.

[drh1965]

Here's an update... WEMA recommended studs for two of the holes. That is, put in 2 studs offset 180. Put in the other screws from the top. Replace studs with screws. Keep studs for next removal. That seemed like a fine idea

I'm just happy to put that mess behind me. My next task is to pump out all the old fuel in the tank. Anyone want some 5 year old diesel?

Thanks!