The Cessna 120-140 Association Forum

Trying to remove LH fuel gauge to get it overhauled and one screw won't budge. All were tight but one won't budge. Tying to avoid drilling it out. Any thoughts?
Alexis Lake

PB Blaster or Kroil
More leverage (Ratchet and socket driver)
Heat (Caution! Fire hazard!)
Shock it with a hammer
Shock it with an impact driver (be careful not to damage anything!)

An old A&P told me to try and tighten (yes, tighten!) it for just a little. Tried it numerous times now, and I'll be darned if it didn't work!!
Copied the following from some old post I found at another site.

" Machinist's Workshop magazine actually tested penetrants for break out torque on rusted nuts. Significant results! They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment.

Penetrating oil ..... Average load

None ............ ......... 516 pounds

WD-40 ............ ...... 238 pounds

PB Blaster ............ ..214 pounds

Liquid Wrench ...... 127 pounds

Kano Kroil ............ 106 pounds

ATF-Acetone mix... 53 pounds

The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic transmission fluid and acetone.

Note the "home brew" was better than any commercial product in this one particular test. A local machinist group mixed up a batch and all now use it with equally good results. Note also that "Liquid Wrench" is about as good as "Kroil" for about 20% of the price."

Just be careful where you use it, 'cause the acetone may dissolve plastics.

8175 wrote: ↑Thu Feb 13, 2020 7:22 pmJust be careful where you use it, 'cause the acetone may dissolve plastics.

the acetone may will dissolve plastics.

Thanks guys. I've tried all but trying to tighten it. I'll try that on Sunday!

Got it out. Enlarged and squared the screw slot, got a larger screwdriver, with a wrench on the screwdrive, it finally came out.