Hi,

I have a Farmall A which is playing up.

The generator belt pulley behind the fan pulley on the fan assembly is spinning freely - that is, when the engine is running and the fan is turning, the generator pulley is not turning at all (and therefore not driving the generator).

There is some play in the pulley (side to side), and it seems to me that there is some sort of shear pin that's... well... sheared...

I can't tell if I have a Service Products Corp fan assembly, or a Schwitzer-Cummins Co one... is there an easy way to tell them apart?

Before I start the process of removing the cowling and radiator to get the fan assembly off, has anyone come across this issue, and if so, what do you recommend?

Cheers,
Perk.

Something may have happened to your generator
internally locking up the generator. After you pull it I would take it to a shop that repairs starters, alternators and generators. Hal

(reply to post at 00:12:08 04/10/12)

Click to expand...

Hi El Toro,

Thanks for you prompt post!

The background story here is that this tractor has been converted to 12v with an alternator (+ve earth with an external regulator) that runs off the generator pulley. I've recently had the alternator overhauled, replaced the alternator bearings and replaced the external regulator - so I am absolutely positive it's not locking up. I can turn the belt and alternator manually - both while the engine is running and when it's not. The belt is definitely not slipping - I've double and triple checked that - it is the pulley that is not turning.

So now that I have a re-built wizz-bang alternator, I'm somewhat bummed that I can't use it 'cos the pulley won't drive it.... grrrr....

Cheers,
Perk.

Time to take the fan/pulley assembly off the tractor, take it apart, and see what's wrong. You're gonna have to take it off to fix it no matter what's wrong. May as well bite the bullet and get to work rather than stand there looking at it while scratching your head.

I have NEVER heard of such a thing happening. I was under the impression that the assembly was one piece of machined metal.

If the pulley is in fact sheared and has been spinning, you may want to consider a replacement assembly because the pulley is now loose on the shaft and may never work right again.

Pull the alternator and see if the alternator has seized causing the pulley not to move. Hal

Perk The generator pulley is driven off the fan pulley. On mine the two pulleys were spot welded together and the spot welds broke leaving the generator not being driven. In my case after being on the tractor for 60 years + the bearing were getting worn bad so I replaced the whole fan assembly.

Perk, I had the same situation on my AV last fall, so we took the pulley and hub off. It looked to be an aftermarket assembly, and the spot welds let go. So my son put some spot migs on it and it works fine. He welded the two pulleys together on their edges.
Also called CIH parts department, they said to bring it in to match it up, they had two different units available and they were in the neighborhood of $275.00. Hope you have the best of luck with yours.
Charlie

Thanks for all your comments.

I'm going to have to bite the bullet and take off the front end, it would seem... but the idea of welding the pulleys together is a good (and cheap) idea that I will be following up.

It's also interesting that there are aftermarket fan units out there - this would explain why I couldn't figure out which mine was from the original parts manual.

Thanks all!

CharlieNJ the original fan assembly was spot welded . Like I said below I replaced the one on my B witch was original and the spot welds gave away and bearings were getting wore bad. I got a replacement for mine from a Case IH dealer about 4 or 5 years ago and gave around $85.00 for the complete fan assembly. I have got some parts lately for B & 450 from CIH and they are selling after market because CIH no longer lists some of the parts an more.

d beatty, thanks for that information. I had figured the cast pulleys were original equipment, and the stamped steel pulleys were "aftermarket", but as you say, the stamped pulleys could be OEM too. I also have a 1947 B, the tractor came to me as a basketcase. Been working on it slowly. Also have a 1947 A and a 1948 Super AV that we work. Looking forward to getting that B running.
Best Regards,
Charlie

Charlie my B is also a 1947 and its been in the family from day one. The tractor has seen a lot of use. It has seen three major overhauls in the 65 years that we have owened it. Does your B have live hydraulic? Ours came from the factory with a C block in it whitch had place to put a pump. In the late 50's my dad put the hydraulic pump on it and built a full hydraulic loader for the tractor and I'am still useing it today.

d beatty, my B has a serial number in the high 212 thousands, which I believe makes it a Louisville product. My A has a lower 1947 number, mid 194 thousands, which would be a Chicago. My B has no hydraulics.
My B was originally owned by the father of the man I bought it from. They had sold it twice over the years, but bought it back both times. The last time, it was in bad shape, been setting in a field with a stuck engine. The son, who has a body shop, bought it with the intensions of doing a comprehensive overhaul. He invested a good sum of money in new parts. He had the final drives off for bearings and seals, and some parts in epoxy primer. Then he fell on hard times due to some marital troubles. The last straw for him was the machine shop, where they lost his cylinder head after an employee was fired.
As a condition of sale I promised to give him first option to purchase the B if I ever sold it. He was relieved to know I was not a tractor trader, and that I was going to put the B to work. Like you, he has a lot of sentimental attachment to his B.
Because the final drives were off when I bought it, we slung it onto the trailer with a front end loader. One of the straps slipped, and the clutch pedal was hanging under the belly. She landed on the pedal first, and snapped the torque tube casting where the clutch/brake shaft bears. So, I got a replacement tube.
Next, had a hard time breaking the engine free. Took a long time soaking to get oil to come out the bottom rings on two cylinders. So I used the barbeque technique, where you partly fill the cylinders in question with oil and mineral spirits and a rag wick. Had to give her two sessions of that, then she broke free with light tapping a block of wood and hammer. After the barbeque sessions the block was warm like she had been running form several hours. The sleaves were really bad.
Next problem was the right side brake drum. Wow, it was like it had grown on the shaft over the 60 some years. Had to use some chain, a 20 ton jack, some steel plates, and a whole lot of torch heat to get it off. It was one of the tightest things I ever pulled. It groaned like a banshee when when it finally broke free, so I backed off with the torch at first, and it just locked right up again. Before the heat did its job, we had the 20 ton jack pushing so hard the pump handle was stiff. Anyway its off now to get to the seal.
Well, can't wait to get it all back together, might take me better part of this year. But I am sure, in the end, it will remain in the family for a long time.
Best Regards,
Charlie

You don't have to take the WHOLE front end off the tractor to remove the fan/pulley assembly. At worst you need to remove the hood, grille, and possibly the fan shroud.