has two plastic holding tanks
, and both have a VDO level gauge/sender that screws into a mounting flange on top of the tank (see photos). On both tanks
, fluid leaks
out from between the mounting flange and the tank surface.
The mounting flange is apparently attached to the top of the tank with self-tapping screws and a rubber gasket
. I haven't taken it apart yet, but I suspect that self-tapping screws were overtightened and threads failed, so the gasket
simply isn't getting compressed enough to form a good seal. Apparently this has been an ongoing issue, since the PO attempted to seal around the perimeter of one of them using caulk or 4200 or something similar... which didn't work
Question is... is there a better way to mount these flanges to the top of the tank so that the mounting screws can be tightened down and the gasket compressed better? Something like this adapter
from WEMA seems ideal, but I haven't found one in the correct size. I could presumably get some nuts and washers on the underside of the tank surface, but I'm afraid the washers would protrude into the thru-hole and interfere with the sensor being screwed into the flange.
Should I use a sealant
in addition to the gasket?
Or possibly a different approach. The sender has 2-1/2" stamped on top of it (seen it labeled elsewhere online as 64mm). I don't know if this is BSP or NPT, but if NPT, could I drill out the hole to 3", insert a 3" Uniseal plus a 3 x 2.5 Spig x FIPT bushing, and screw the sender into that?