What is the Name of the Tool to Remove this Nut?

[Wotname]

Originally Posted by lifeofreilly57

"Gentle" heat won't work, to break a corrosion bond requires a very hot concentrated heat source of heat. An aceteline torch or at least a MAP gas torch would be more appropriate, rapid heat on a concentrated area will usually do the trick. But if there are rubber gaskets or hub bushings that's not an option. Freezer suggestion sounds like a good alternative.
However, if there are no rubber parts and it's a steel hub with a frozen nut, poor the heat on the nut hard and heavy until it is smoking hot, then try to remove it. Your trying to make the nut expand faster than the threaded shaft it's on to break the corrosion / torque bond it's stuck on with. Slow heat tends to expand the nut and the shaft with no dimensional advantage.
I worked in spinning mills in high school that used 1850's vintage equipment, then into working as a millwright in chemical plants, in both cases I took apart some extremely corrosion bonded parts.

I do hear you, just recently had to remove a badly rusted shaft from a badly rusted arm. Much heat (MAPP gas) and a 4lb hammer wasn't enough but it came apart with 10lb maul on a 3' handle

However in this case, I don't believe the nut is badly frozen to the thread, rather I don't have a suitable tool to grip the nut in order to get sufficient torque onto it. Hence the question about the name of the correct tool.

[model 10]

You need a Ford wrench. Everybody should have one.

[Jim Cate]

wottie, have you tried Reducteur H-72 on it yet? Stuff has worked magic for me on rusted steel bits. And as to the tool, I take it that you can't get a shifter (Crescent wrench to us yanks) in to grab the flats.

Jim

[ValiantV]

It looks to me as if that "nut" is actually part of the pulley.

In other words, the pulley seems to be threaded onto that shaft.

I don't see any parting line or seam.

Us there a flat or hex behind the pulley? Perhaps a way to lock the shaft and unscrew the whole pulley?

[newhaul]

Originally Posted by Wotname

Hmm... yes, this is a tool that might work. The OD of the nut 1.25" and I note the largest Gator Grip is good for 1.25"; presumably that is 1.25" AF, so it should fit.

Another possibility considering the size would be a crows foot wrench.
https://www.amazon.com/crows-foot-wr...oot%20wrenches

[Jim Cate]

Originally Posted by ValiantV

It looks to me as if that "nut" is actually part of the pulley.

In other words, the pulley seems to be threaded onto that shaft.

I don't see any parting line or seam.

Us there a flat or hex behind the pulley? Perhaps a way to lock the shaft and unscrew the whole pulley?

If that is true, then a big strap or chain wrench (spanner) on the pulley would give a lot of leverage.

Jim

[Wotname]

Originally Posted by ValiantV

It looks to me as if that "nut" is actually part of the pulley.

In other words, the pulley seems to be threaded onto that shaft.

I don't see any parting line or seam.

Us there a flat or hex behind the pulley? Perhaps a way to lock the shaft and unscrew the whole pulley?

The nut and pulley are separate items, the parting line is there in real life, just not clear in the photo.

Although I can't be 100% sure until I get it apart, I think the pulley is keyed to the shaft.

[Wotname]

Originally Posted by Jim Cate

wottie, have you tried Reducteur H-72 on it yet? Stuff has worked magic for me on rusted steel bits. And as to the tool, I take it that you can't get a shifter (Crescent wrench to us yanks) in to grab the flats.

Jim

Yes to the H-72; it is my goto can of spray

A shifter (Crescent) doesn't get into the pulley hub depression (if that makes sense).

I was going to try a larger shifter (24") using it the "wrong" way, at 90 degrees to the normal sense i.e. putting the jaws onto the nut in the same axis as the shaft and using another shifter to rotate the jaws on the first.

Still trying to find the correct engineering tool first!!!

[Wotname]

Originally Posted by newhaul

Another possibility considering the size would be a crows foot wrench.
https://www.amazon.com/crows-foot-wr...oot%20wrenches

Haven't tried a crows foot yet but don't think the diameter of the inside of the pulley would allow it to fit but will investigate further, thanks.

[Kenomac]

Will an adjustable spanner do the job? It appears to be reverse thread, clockwise to undo.

[Orion Jim]

Originally Posted by Wotname

Yes to the H-72; it is my goto can of spray

A shifter (Crescent) doesn't get into the pulley hub depression (if that makes sense).

I was going to try a larger shifter (24") using it the "wrong" way, at 90 degrees to the normal sense i.e. putting the jaws onto the nut in the same axis as the shaft and using another shifter to rotate the jaws on the first.

Still trying to find the correct engineering tool first!!!

That's what I'd do because I have some very large crescent wrenches. There have been times when welding a standard nut to a troublesome nut has been the expedient alternative. Then you just use a standard socket and breaker bar on the nut you just welded.

[Wotname]

Originally Posted by Kenomac

Will an adjustable spanner do the job? It appears to be reverse thread, clockwise to undo.

Hmm... I think the opposite

The slope of the visible thread seems to go from high on the LHS to low on the RHS (looking at the image) and this is the same as a standard nut - I think but I could be wrong

[Kenomac]

Then I'd call Yanmar to find out what they recommend.

[jimbunyard]

'Gentle' heat is not what's needed here. Looks like L/H thread to me, but enough thread is visible to tell for sure in person.

If you have access to a welder (and something tells me you do) a very simple tool to remove this can be made with 2 pieces of 1/2" (or so) steel key stock, a 3" x 3" (or so) piece of 1/2" steel plate and a 1" (or so) nut.

Mark the center of the square plate and weld the nut to it. Mark the center of the other side and weld the two pieces of key stock, from this center mark, parallel to each other, half the distance of the total width between the flats of the 'nut' holding the pulley on.

Secure the assembly holding the pulley and nut very strongly, a big vise or clamped to an immoveable table would be ideal.

Get a 1" (or whatever size nut you've welded to the steel plate) socket and breaker bar or such ready.

And here is the important part...quickly heat the 'nut' holding the pulley on with an ox-acetylene torch as much as possible, just before dull cherry red would be about right, immediately you've got it hot, put your homemade tool on it and break it loose. If it turns a little and locks back up, let the whole assembly cool (or quench it yourself) and do the heating thing again.

Sometimes dousing the threaded area with some kind of penetrant in the cooling part of the cycle will help speed things up...

The idea of quick, strong heating is to get the nut to expand before the shaft does, and turn it off before the expansion of the shaft equals the expansion of the nut. Hence the (general) futility of using propane or Mapp gas in this application; one can't add enough heat quickly enough to take advantage of the differential rates of expansion...

[Seeking Solace]

Maybe this will help? If nothing else you'll have a PDF of the service manual. It gives detailed instructions.

http://seekingsolace.28thid.us/Yanma...e%20manual.pdf