JD 40 Fan Belt Replacement

[saxnbees]

I need to replace the fan and generator belts on my JD model 40 tractor but cannot seem to find much information on the net. I have removed the sheet metal exposing the engine and radiator areas. I have also moved the coil and generator out of the way. I have obtained a 1 7/16 wrench that fits the large nut on the back of the fan assembly. However, I have not been successful in loosening the large nut. I have been applying penetrating oil and tried hitting the end of wrench with a rubber mallet but with no luck so far.

So, before I break something, I am asking for advice.

The first question I have is the thread on the large nut...is it a left hand thread? Or am I actually making the nut tighter unknowingly. Is there a better way to loosen the nut?

Beyond that, can you impart any suggestions or advice on the best way to remove and replace the belts once I get the nut loose? There is not a lot of working room in there and any suggestions are welcom.

Thanks.

 

[beenthere]

Can you post a photo or two of the area ? Been awhile since seeing the two-cyl 420 but have a faint memory of changing the fan belt. Maybe a pic or two will refresh that memory.
Member Tx Jim has good experience and may see your post too, as well as others.

This video help any ?

 

[saxnbees]

Thanks for the video but my problem concerns the large nut at the back of the fan blade assembly. Here's a couple of pictures of the area.

 

[beenthere]

Maybe easier to remove that fan bracket (key#4) that the nut is attached to for better leverage (heat ? ).
Suspect that large nut is regular rh thread.

 

[saxnbees]

Thought about that possibility but temporarily rejected the idea because it looks like some other stuff is bolted to it and it will be tough to get the whole assembly out of the space. Thanks for the idea...I may eventually come back to it.

 

[oldtimer 66]

My neighbor has a impact tool/ muffler gun with a special driver that he uses to remove clutch type fans, It impacts against a standard wrench. and or the set of wrenches that came with the tool.

Here is a tool from amazon https://www.amazon.com/BETOOLL-Pneu...cphy=9006414&hvtargid=pla-2281435179498&psc=1

 

[saxnbees]

Interesting. Thanks for the suggestion.

 

[DJ54]

Is it necessary to remove the fan at all..?? Try slipping the belt over one fan blade at a time. Should be enough room for it the belt to fit between the radiator and fan if you loosen the fan to adjust it.

 

[saxnbees]

The problem is that the nut in question is what loosens the fan assembly to adjust the tension on the fan belt. To this point, I have been slightly successful in that I can now move the assembly up and down a bit. If I can move it enough to get the belts on and off as you suggest, I could consider a means of pushing up on the nut to adjust the fan belt tension, maybe a wooden wedge? or a piece of steel with a couple of adjustment bolts?

 

[DJ54]

You may be able to put a pry bar on the washer behind the nut and slightly pry upwards and still be able to turn the nut.

 

[saxnbees]

I am not sure what you are suggesting. The problem is that I cannot turn the nut. It is frozen to the shaft on which the fan assembly is mounted. It is likely 40-50 years if not longer since the nut was turned and has rusted to the shaft. Unfortunately, everything is pretty tight so there is not much room to apply penetrating oil. There is also almost no threads exposed to apply oil to.

I am getting closer to your previous suggestion where I would try to replace the belts without removing the nut. Then I would need to adjust the belt tension with a pry bar and come up with a way to hold it in position since the nut cannot be tightened either.

 

[Fuddyduddy1952]

Maybe this will help(?).
Years ago I needed to replace the clutch fan on my F150. The nut was 1 5/16" from memory (large). I tried everything. Then remembered I had an air chisel. It was right hand thread so I put chisel on nut flat right at edge as shown. Bad drawing but you get idea.
It was easy, apparently the vibration spun it off and as it turned put it on the next flat as it turned.

 

[saxnbees]

Good idea if I can get the chisel in there. Do you remember whether there was any damage to the nut? I have done similar with a screw driver and hammer in the past.

I think the trick is that there is a lot of instantaneous power released every time the hammer hits....more than you apply with a wrench.

Thanks for the suggestion.

 

[Fuddyduddy1952]

I used a chisel that needed sharpening and no damage to the nut. In my case the new clutch fan came with new nut anyway.
It worked well for me.

 

[saxnbees]

Thanks for the feedback. I am at the point where I am going to try replacing the belts over the fan without removing the nut. But that may not be possible for the generator belt as it is much smaller than the fan belt. When I bought the belts, I never thought this would be such a difficult task!

 

[beenthere]

Fuddyduddy1952​

I'm thinking this '50's model 40 doesn't have a clutch fan and new parts are not available. Finding a new nut to fit the threads might also be a real problem. Risk of breaking the cast frame that holds that fan axle in place may be found in a parts house, and might be worth a search before risking breaking something.
I'd be trying continued use of a good penetrating oil (something like kroil or a new one I've found to be the best available, is "blue creeper" from Logrite)

 

[saxnbees]

Update. Decided to just try and remove the belts from over the fan. That was a success. However, there is one tight spot that has become a problem in installing the new belts. There is a spring loaded shaft that is pushed into a couple of detents on the crankshaft for crank starting the engine by hand. The old belt fit through the gap between the start shaft and crank pulley because the belt was worn so thin on top. However, the new belt is much wider and does not want to go through the gap.

Any ideas out there? Can the spring loaded starter be removed easily....or pulled back somehow?

 

[saxnbees]

I think I just figured out the starter issue. Apparently this type of hand starter only exists on the tricycle model of the JD 40. There is a spring clip that holds the starter in position. Pop that off and the starter can apparently be pulled back out of the way or maybe removed. I may not be able to put it back once it is off because it is tight in there....but when will I start it by hand anyway? I have no clue where the hand crank is....

 

[beenthere]

Hand crank assembly from jd parts, and hope you are zeroing in on the right solution.

https://partscatalog.deere.com/jdrc/sidebyside/equipment/2803/referrer/navigation/pgId/1853358

 

[Fuddyduddy1952]

Fuddyduddy1952​

I'm thinking this '50's model 40 doesn't have a clutch fan and new parts are not available. Finding a new nut to fit the threads might also be a real problem. Risk of breaking the cast frame that holds that fan axle in place may be found in a parts house, and might be worth a search before risking breaking something.
I'd be trying continued use of a good penetrating oil (something like kroil or a new one I've found to be the best available, is "blue creeper" from Logrite)

I agree Kroil or good penetrating oil. In my case with air chisel it was super easy after hours of trying everything imaginable. I wasn't using lots of pressure either and just the vibration and that angle was enough. Once started is all that's needed.
Like everything, use your own judgement.