Fuel Tank Inlet to Cab Floor Seal

[tonybiel]

Would someone please let me know how their fuel tank inlet is sealed to the cab floor?  I have a 1951 B3C.

 

I purchased a foam seal from DCM as they showed that it fit 1936 to 1953.  As you can see in Pic 1 under the cab (sorry the pic is upside-down), the cab sits 2 inches above the tank, so the seal is not thick enough. The top view from inside the cab, Pic 2 looking down at the tank, you can see that the seal is also not wide enough to cover the hole in the floor of the cab.  Pic 3 is the original rubber boot that I removed, which was just sitting loose over the hole in the cab floor.  Can't tell if the boot is factory, but otherwise, someone did a nice job of cutting it. Pic 4 is with the boot installed.

 

Notice back on Pic 2 that there are 4 apparently factory drilled holes in the cab floor as if it were intended for there to be a metal plate securing the boot to the floor.  However, there was no plate, no holes in the rubber boot for screws and the holes in the cab appear that they never had sheet metal screws installed.

 

Does your truck have a similar rubber boot on top of the cab floor or is it sealed from underneath?  If there is a rubber boot on top, is there a metal retainer securing the boot to the floor?

 

 

[Dodgeb4ya]

The rubber flat boot is factory.

If your truck cab was mounted on a heavy series...say 3-4 ton truck generally those trucks used larger capacity saddle outside frame mounted fuel tanks instead of the small under cab 18 gallon tanks.

This required a square metal plate screwed in four places over the hole where the std tank neck comes up through the cab floor.

 

[tonybiel]

Great explanation.  Makes sense.  I'll make a new boot and maybe improve it a little for a better seal.  Thanks for the info!

[JBNeal]

additional information - Cab Floor to Filler Neck Seal