Seeking spacing spec btween fuel sender & tank

[im3crazy]

Finally got the tank from hell back in the car and installed the sender and 2 gal of gas.

Seems the tank not only rusted but it shrunk when the 3 stooges at the radiator shop worked on it! Looks like they dented it just right to mess this up.

Does anybody know what the space between the base of the fuel sender and the tank should be about?? Right no I'm at "0" and I'm pretty sure that's not quite right!

My fix is gonna be a short baseball bat, a big hammer, and about 100 medium raps until it meets whatever spec u tell me is about right.

Thanks.

.

[Bill_Riblett]

You want the sender bottom to be as close to the tank bottom as feasible, since this is the gas pickup point.

Seems to me that thumping it with a bat should work well, but you probably won't need a lot of force.

[im3crazy]

Thanks Bill. It seems like a simple question, but I've learned that what often appears obvious on these cars isn't. I was guessing 1/8" or so but would not be surprised at a larger required/designed gap.

I also noticed I get an air leak/whoosh from O ring seal of the sender when I press down slightly compressing the tank. Seems I have a small gap somehwere there. I replaced with the original O ring after liberal electrical silicone lubing, but I'm hoping deepening the tank a little will solve this leak.

.

[Bill_Riblett]

Did you use a new genuine BMW "O" ring? They apparenly expand with contact with gasoline.

[boxy02]

Did you use a new genuine BMW "O" ring? They apparenly expand with contact with gasoline.

Got a part # handy by chance ( I'll look on Real OEM, too).

Mike

[BillWilliams]

These are the part numbers for the sender and pick-up. Twist in style

[jgerock]

If you can press down on the top of the tank and either hear air escaping or fuel pouring out, then you might have a bad sealing ring or the wrong one.

The BMW factory manual suggests to only use a correct sealing ring(s) and to apply a light coat of vasoline ("lubricant") to prevent the ring from tearing while the pickup/sending unit is twisted in place.

I recently replaced my pickup sealing ring and crossing my fingers it doesn't leak fuel all inside the trunk. Lately, I haven't been filling it up all the way.