MF31 drive pulley

[JML755]

I've got a Massey Ferguson MF31 sickle mower that I bought at auction for a couple hundred bucks. My plan was to use it to cut along pond/creek banks and in the vertical position as a "hedge trimmer" to keep paths clear of overgrowth. So far, I 've just used it in the vertical position and it works great. I haven't changed any knives or anything on it....yet.

Last week I was trimming some paths and the tip got caught on a branch it couldn't cut. I always trim at lowest gear/speed just so I can catch that kind of stuff. It stalled the mower ??? and I shut down as quick as I could. Turns out that the bar pulled backward far enough to pull the drive pulley out of alignment and the belt caught on the frame. Looking at the frame structure (and the parts breakdown) the only way I can see that happening is to twist the main tube that the drive pulley, idler pulleys and the head are all mounted on. There is no obvious distortion or cracking on the tube at all. The idlers are still in line with the head so it's the drive pulley end that got twisted. It appears that all I've got to do is cut the mounting bracket for the pulley trunnion, rotate it back in line and reweld. Anyone experienced anything like this before? Is my thinking correct on the solution (cut/rotate/reweld)?

Also, as you can see the drive pulley has seen better days. (This was the condition when I bought it).

I'm amazed it's held up this long and as long as it was working, I didn't want to mess with it. Well, now that I'm going to disassemble the drive, I figured I'd address the pulley as well. I could only find one in a Google search, several years old on ebay and it's long gone. I've found some pulleys, close in size, C belt that you specify a bolt-on hub for. However, when I removed the pulley, I found that the shaft is tapered with a keyway (1.05" down to .810). This is over a 1.5" length, so about 1.5"/ft. if my math is right. There are tapered hubs out there but before I go crazy trying to see if one will fit, I thought I'd pick the brains of guys on here. Anyone run into this before trying to replace that pulley and come up with a workaround using available parts?
Thanks for any help you can give.

 

[MF#1]

Look at the yellow circle, loosen that bolt and you should be able to straighten without cutting. I have a pulley that would probably fit, in KY.

 

[JML755]

(quoted from post at 23:10:58 06/26/18) Look at the yellow circle, loosen that bolt and you should be able to straighten without cutting. I have a pulley that would probably fit, in KY.

MF1: I thought the same thing, so I loosened the bolt and pulled it as far over as it wanted to go with a pry bar but it didn't seem to move far enough. I'm going to remove the springs/tie rods that hold the main tube to the structure and clean everything up so I'll try to realign it again using that method before I do any cutting/welding.

Can you describe the "probably fit" pulley"? Is it off a MF mower? How much do you want for it? Thanks for responding.

 

[RM-MN]

That should be a low stress pulley and most likely broke when the previous owner backed into something. I wouldn't be stressed out trying to replace it unless it shows signs of breaking anew.

 

[JML755]

I was wondering the same thing (how it broke) as there is very little stress on it. With a mostly solid web, I would think the belt would slip or the shear bolt on the PTO shaft would break before the pulley broke. Also, it's been running fine for a couple of years even with all the cracks that are in the welds. They were all there when I got it.

 

[Hay hay hay]

I had 3 MF41 mowers (all bought used) and the frame was bent in every one. I think someone had hit a limb or door jamb
when the blade was in the upright position. I took each one apart and had them straigtened. A 41 is different than
your mower, so my fix won't help you, but be aware of the vulnerability of the machine...and be careful after you get
yours fixed. I once sold an M31 parts machine for $100, had all the parts you need...but that was 10 years ago. try
craigslist for a whole machine..that is where I sold mine.

 

[JML755]

Yeah, I don't want to put TOO MUCH into it as it only cost me a few hundred. But.... a broken one is useless to me. Been looking for MF31's here in Michigan. Haven't seen many over the years. If I could get another one reasonable, I'd probably spring for it. However, the wife still wonders why I need TWO tractors. I can't imagine trying to explain why I need TWO of the same mower. :lol:

 

[MF#1]

According to the Owner's Manual it has a range of 14 degrees total, 7 degrees above and below. The big nut is actually a locknut, the cam bolt head behind it is where the adjustment is, it's probably rusted badly in place. I wouldn't take those springs loose unless I was wanting to get really deep in a mess ;-)BTDT.
The pulley is off of a MF 41 mower but should fit, it looks the same as the other 31 I have.
I should be able to get a look at it on Saturday if you're interested.
Price? It can't be worth much

 

[JML755]

(quoted from post at 16:50:04 06/27/18) According to the Owner's Manual it has a range of 14 degrees total, 7 degrees above and below. The big nut is actually a locknut, the cam bolt head behind it is where the adjustment is, it's probably rusted badly in place. I wouldn't take those springs loose unless I was wanting to get really deep in a mess ;-)BTDT.
The pulley is off of a MF 41 mower but should fit, it looks the same as the other 31 I have.
I should be able to get a look at it on Saturday if you're interested.
Price? It can't be worth much

I WAS able to get that adjustment to move, probably within the range you mentioned, but not enough to fix the issue. Thanks for the advice on the springs.

Don't make a special trip or anything but if you can take a look at that pulley on the 41 this weekend, I'd appreciate it. However, if it's the style with 4 bosses on the web, it appears to use a splined drive shaft (both ends) while the style I have uses the tapered shaft and standard shaft on the PTO end. It wouldn't work unless the shaft came with it. Plus, I'd need to get a splined PTO shaft both ends. Not a huge deal but just extra stuff to make it work.

 

[MF#1]

I need to go by there anyway so no problem. Thanks for pointing out the differences, I will be sure to check it out.
I will post back, hopefully by Saturday evening. I wish you were closer, I could set you up with the frame parts very cheaply.

 

[MF#1]

Sorry but I don't think mine will fit :-( Maybe yours is an early model. I didn't take anything loose but the outward appearance is different unless you wanted to swap out the shaft and associated parts.

 

[JML755]

(quoted from post at 20:23:52 06/30/18) Sorry but I don't think mine will fit :-( Maybe yours is an early model. I didn't take anything loose but the outward appearance is different unless you wanted to swap out the shaft and associated parts.

No problem. Hey, thanks for looking. I'm going to first work on realigning the structure, put the pulley back on and then hopefully I can take my time looking for a replacement, either looking for MF31 parts locally or retrofitting with a new pulley close in size and hub. Maybe JB Weld on the cracked one?

It uses a C Section belt. Was wondering if I can get away with changing to an A or B section. Those seem to be cheaper, more available.

Right now though, I've got truck problems. Went to start my F150 last night, no click, just smoke coming from under the truck. Suspect a starter solenoid or starter. I know what I'll be working on today.