Gas tank rattle is driving me nuts!

[Smitty550]

A rattle coming from inside the gas tank (not behind it) is most annoying. I am guessing that part of the sending unit, including the float, might be the culprit.

I have no idea if baffles were part of the construction of gas tanks in 1967 C10 Chevrolet trucks, but is if so, is it possible that a baffle might have fractured off inside the tank?

The tank is placed vertically, located directly in back of the seat back. It is bolted to the interior of the cab. The seat is not the cause of the rattle. Also, there is only open space between the front of the truck bed and the cab.

I have checked the undercarriage beneath the truck, and found nothing. At this point, I'm stumped! So....any thoughts?

[maxwedge]

Run the tank to almost empty, hit it with a rubber hammer, if the noise can be duplicated, then the tank must come out for further evaluation.

[Smitty550]

Thanks, Max. I'll give it a try. The seats are now out of the truck, awaiting their replacement, but only after the DynaMat has been placed onto the floor (it was delivered to me just yesterday). After the seats are back in, I'll drive the truck to get as much gas out as possible, then give it the hammer treatment.

[777stickman]

Or maybe siphon the gas out now since the seat is out?? Rubber mallet tapping as the gas drains??

[Smitty550]

Thanks, Stickman. I plan to drain the tank, but first I will remove the sending unit to see if the float is loose, etc., then I'll take it from there. I will probably end up removing the tank anyway because I would like to place DynaMat insulation behind the tank, then follow up with covering the floor of the truck before the seats are replaced, along with new retractable seat belts.