fuel tank seal

[DollyDodge]

When I pulled my fuel tank our of my B2, there was a single piece of rubber about 4 inches by 6 inchers that fit around the tank where the filler tube comes into the cab. It was glued to the floor of the cab. It looks like though that originally there must have been a better seal, grommet, or gasket because there are 4 screw holes in the floor of the cab around the filler inlet hole. What should be the grommet or gasket around the filler tube? Does anyone have one?

Rob

[Dodgeb4ya]

The rubber is correct for all lower tonnage trucks with the gas tank mounted under the cab. If it is a higher tonnage truck- and has the factory installed 25-40 gallon saddle tank or tanks , there is a steel cover plate screwed to the floor where the under cab tank filler neck should go with the rubber seal.

Bob

[MBF]

Mine had a piece of rubber about 1" thick heavy foam rubber that went on top of the tank over the neck, and fit between the top of the tank and the cab floor. My parts truck had a piece made out of an old mudflap. Mike

[JBNeal]

my '48 had the foam rubber, or at least a very degraded spongy rubber-like substance that I have stashed in my archive (aka paper box in the garage). My '49 had a bicycle innertube shoved down in there, I reckon to keep the rats out. My guess is that since the frame of these trucks is riveted rather than welded, there is a fair amount flex shown when taken off road. So they put some soft rubber around the fill neck to keep the cab from sawing into the tank when fording creeks or crossin' ditches or whutnot.

[DollyDodge]

Dodgeb4ya, do you have a picture of the cover plate, or does anyone else have a picture, or better yet, one they would sell?

[John-T-53]

One of these seals could be easily made from a piece of flat rubber, like an old floor mat. Napa sells rectangular black rubber floor mats for cheap that would work great for something like this. The seal should be about 1" larger than the hole in the floor. The hole for the fill tube is elongated since the tube passes through the floor at an angle. For mine, I used the old one, but cleaned it up with acetone. I glued it to the floor and also used some good ol' duct tape to hold it in place (I stepped it up and went for the black duct tape). Then I generously caulked around the fill tube. It ain't pretty, but it's outta sight!

[grey beard]

I worked in the heavy truck industry for many years. On top of most heavier transmissions at the shift tower, where they pass through the cab floor is usually a one-or-two inch thick piece of foam rubber - sort of a draft gasket. This works very well, especially with something that may squirm around - like a tranny on motor mounts - or a gas tank on straps. When I rehabbed my Pilothouse, I put a piece of this stuff over my gas tank neck before I put the tank back up in the frame. I also put a piece on top of my trans shift tower before I put the floor plate back down. It is a way of sealing the gap from the bottom, as it were.

After everything's back together, go to Lowes roofing department and get a roll of Peel 'n Seal butyl rubber roofing patch made for fixing valleys and such, and use this stuff for a positive seal around the top of the area - after you paint all your sheetmetal with ZeroRust or RustBullet, to keep the rust down. This stuff is good draft sealer and good sound deadner for any panel. I used it on all the inside surfaces of my cab - even the roof. Makes for a quieter ride . . .

[John-T-53]

Hey Greybeard, that's a great idea to use bituthene (bitch-a-thane) as sound deadener. I'll bet it's pretty much the same material as Dynamat, but a lot cheaper and doesn't have to be catalog ordered. I have some left over from my roof I'm going to put in my truck parts box right now...

[Dodgeb4ya]

Dodgeb4ya, do you have a picture of the cover plate, or does anyone else have a picture, or better yet, one they would sell?

Here are the requested pic's.

Bob

Edited January 11, 2010 by Dodgeb4ya

[DollyDodge]

Thanks for all the info and the pics.

Rob