HELP. Stuck Crank Nut on an Elgin Twin 20

[MOTOmike]

I have an original paint, Elgin Twin 20, Murray-built frame, and I'm fairly sure the crank nut has never been removed. I have sprayed this nut, off and on, for months with Aero Kroil penetrating oil.

First off... I would like to have someone confirm that this crank nut is reverse thread. The only tool I have to try unscrewing this crank nut is a large crescent wrench. But with increased pressure, it "slips" off the nut where the two grooves are.

Does anyone have advice on what I could try next? Should I try heating the nut?

Any suggestions will be appreciated.

Thanks,

Mike

 

[Autocycleplane]

Can confirm, these are a hassle when stubborn. All looks, no function - super easy to strip the two shallow wrench flats.

I would file those wrench flats to make sure you can get a good grip on them, then clamp that nut in the jaws of a vise to get it moving using the crankarm for leverage.

 

[THEGOLDENGREEK]

Adjustable wrench or last resort plumbers wrench, maybe apply some heat to it to break the rust on the threads and yes it's reverse thread on it , best of luck!

 

[catfish]

Are you turning it the right way?

 

[catfish]

 

[scootergenius]

Dremel a cut into it with a small cutting wheel, not quite all the way through, to spare the crank threads, then use a small drill bit to weaken what's left of the cut. A good pop with a wide cold chisel or similar will split the nut, then it can be pried open and removed. You'll need a new nut, but the old one will be off. This has worked for me on lots of occasions. good luck!

 

[morton]

1

 

[morton]

I have an original paint, Elgin Twin 20, Murray-built frame, and I'm fairly sure the crank nut has never been removed. I have sprayed this nut, off and on, for months with Aero Kroil penetrating oil.

First off... I would like to have someone confirm that this crank nut is reverse thread. The only tool I have to try unscrewing this crank nut is a large crescent wrench. But with increased pressure, it "slips" off the nut where the two grooves are.

Does anyone have advice on what I could try next? Should I try heating the nut?

Any suggestions will be appreciated.

Thanks,

Mike

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If mine I would.....

1.Wire brush and clean. I see too much crud in your photo and penetrents cannot get to where they need to be.

2. Flood the area with Blaster or your favoite penetrent and wait a few hours. Try to remove and repeat numberous times until loose. NOTE WD-40 is NOT a penetrent or "rust buster."

3. Heat with propane torch and try to remove while still hot. Since the nut will expand slightly, shoot it with penetrent each time which gives it a chance extend it's reach. Keep flame away from chain ring as excessive heat could warp it.

4. Alternately try one of the "Freeze" sprays. They too slightly change the size of the metal and inject a penetrent. I've had good luck with these.

5. Destruct and conquer. With a dremel cut a small notch in the nut, insert a pin punch in the notch, and give it a few wacks. This has worked for me in the past on the most stubborn ones and since I cut a very small notch, was able to reuse the nut. The jolt of the hammer blow acts like a air wrench. But the bigger the notch, the less likely the nut will be reuseable. I do this when nut is still hot or cold from steps 3 or 4.

6. Use a dull cold chisel instread of a pin punch. This will likely change to shape of the nut and render it unusable but you will get it off most times..[/QUOTE]

Note: I found that repeatedly yelling out foul language when no one is home sometimes helps. Call the nut every disgusting thing you can think of and some times you can shame it off.

 

[MOTOmike]

Thanks for all of the suggestions...

I cleaned up the area around the crank nut with a brass wire brush...
I sprayed more penetrating oil...
I tapped on the crank nut...
I heated the crank nut with a propane torch...
I tried the adjustable wrench one more time... no go.
I gently tried a small pipe wrench, tapping on the handle, and finally success! The pipe wrench only put 2 small marks on each side of the crank nut so I was able to re-use the original nut.
The 79 year old grease was cleaned from the bearings and bearing races and replaced with new grease.
The crank has been reassembled.

Mike

 

[HIGGINSFOREVER]

Next time back off the race with the two slots with a small flat point chisel and hammer