Suggestions for removing sender unit from aluminum fuel tank on boat?

Question

The fuel tank sending unit (arm) failed along with the gasket seal between the sender and the tank. The bolts holding the sender to the tank have corroded welding them to the tank. The mechanic broke a bolt and said he wouldn't go any further! Any suggestions for freeing the bolts, super penetrating, or am I reduced to breaking the rest of the bolts taking the sender off and either filing or dremeling the frozen bolts and realigning the new sender and drilling? 1988 33 Egg I believe the tanks are aluminum. I undestand that aluminum won't spark when drilled? Correct?

Answer 1

your best bet is to break off the remaining bolts and drill and tap new holes.you can completely drain the tank and run an exhaust pipe from a small engine into the tank for a few minutes to eliminate the chance of an explosion,the carbon monoxide displaces the oxygen vapors and the tank can't explode.

Answer 2

If the bolts holding the sender are dissimiliar metal to the tank and sender, you have galvanic corrosion occuring and the best way to remove them is to heat them up with a torch or possibly Mapp gas. Being that it's in a fuel tank...not a good idea unless you can drain the tank completely dry with no fumes. If you do heat them up, try rubbing some candlewax around the threaded area or under the bolt head if possible and let it melt into the threads....it's an old trick I learned from a junk yard guy and they know about rusted stuff. The wax is actually thinner than water when heated up and will flow into the crevices between the threads by capillary action, loosening them up if it's possible.
The only other solution is to drill out the bolts carefully, peel out any old thread and retap the holes. And use better bolts this time.........Paul

Answer 3

Go to drug store and get small 1 oz bottle of oil of Wintergreen, put a few drops on each bolt and let soak for half hour then try removing them . This stuff stinks to high heavens, smells like Pepto Bismo. only 100 stronger. but if the bolts will come loose when all else fails this stuff will do it. We used it in the Engine and Boiler rooms on ship in the Navy .

Answer 4

Laziness and being disassociated with the people around me. This usually comes and goes. I just have to reignite the fire inside. Bad things happen at precisely the right time usually just before they fade into something new and exciting. Things seen in the past become unseen and the things unseen become visible.