How to: remove rusted nuts from fuel tank assembly

[Bushwick]

I popped the cover for the first time to the fuel pump access hole, and saw nothing but rust, then saw the tiny studs being held in place by 5/16" nuts (might be metric, 5/16" was snug with all the rust).

 

Busted out WD-40 (only thing on hand) and soaked everything down. Then was surprised everything cracked loose w/o instantly shearing the skinny studs, but after a couple turns, the nuts would bind. I went a little further hoping the binding would stop and sheared the stud right off. What to do?

 

Not wanting a bunch of sheared studs, I tried tightening one back down, spraying again, then loosen until it started binding (maybe around 5 ft/lbs of resistance) and tightened again, sprayed more WD-40, then backed off further, and each time the nut loosened a little more.

 

That worked for the remaining nuts and thankfully each came off after only loosing one, which shouldn't be too much of a concern. I never tried that method before with re-tightening once it binded, then spraying the threads down again. Worked like a charm though and figured it was worth sharing. My fuel pump appears to have never been removed in 21 years, and it's seen it's share of winters. Hope it helps someone.

[WoodsWagon]

Yup have to do that all the time with rusty bolts, you're essentially doing what you'd normally do when cutting new threads with a tap or die.

 

When those nuts are so rusted that you're pounding undersized sockets onto them to try and get enough bite, you have to escalate to heat. Before I got an inductive heater, I'd use the oxy/acetylene torch with a welding tip to put focused heat on. Dangerous game to play with open flame on a rusty gas tank, but theoretically the fuel vapor concentration in the tank should be above the flashpoint. Still, would not recommend it especially with inductive heaters on the market that can make a rusty bolt glow red without open flame. Also comes in handy for loosening brake line flare nuts without burning the paint off the line. Mini-ductor is one brand. Fluxeon is what I use, and you wind your own coils to suit out of 10g copper wire.

[screwbaru2]

Another "trick" you may want to try with rusty or stubborn nuts/ bolts is to tighten them just a little just, to get it too move.  For some reason I cannot explain rusty fasteners will turn in the tightening direction much easier than the other direction.  Once they move they loosen much more readily.  

Edited March 24, 2016 by screwbaru2

[Fairtax4me]

I usually try to wire brush the threads and blast them with compressed air to knock the scale and dirt away before trying to loosen rusty fasteners.

 

Still might have to work them back and forth a few times but it makes it a lot easier when you're not compacting rust into the threads.

[Bushwick]

^ I honestly never really thought about it having to compress the rust flakes before. Large bolts seem to tolerate it quite easily, and normally smaller bolts snap before even cracking loose. Was just thrilled all but one were saved and were able to be reused. They got lathered in anti-seize for being such dedicated little soldiers and not giving up!