MF 120 baler VICTORY!!

John S-B

Well-known Member
So I screwed up some courage to take apart the sprag clutch for the slip clutch assembly. I was nervous because the dealership that I took it to was afraid that they would destroy it. I used a large punch and a small ball peen hammer to punch out the brass retainer, and it came out much easier than I thought it would. I used a pry bar to gently pull the sprag clutch out. I'd soaked it in Evapo-rust for about 20 hours, but there was still some chunks of crud on it. It's clear that sprags DO NOT like dirt. After a good scrub with a small wire brush and about a half a can of brake cleaner, I got it as clean as it was going to be. The small sprag pieces can come out of the cage pretty easily, so you have to be careful. It was apparent that the sprag had been taken apart before by marks on the back side of the brass retainer. After cleaning,I started reassembling the sprag clutch. I had a heck of a time trying to get the PTO yoke to go back in. I used a few choice words, (I stock a very large assortment of those, to fit any specific situation...) and fought with it for about an hour. I finally realized that some of the individual sprags were in backwards. They're only about an inch long, and about a quarter inch tall, but they are sort of shaped like an hourglass end to end, but the top and bottoms are NOT the same. The side that goes to the PTO yoke is eccentric on one side, and there's no marking to differentiate them. You have to look VERY CLOSELY to see the difference. So I carefully made sure that they were all aligned, and then it worked the way it should. So I'm going to clean up the slip clutch surfaces, and reassemble it.

Now let's hope everything else works the way it should.

A couple of thoughts on this design. These kind of sprag clutches are a terrible design. The small pieces wouldn't take muck corrosion or chips for them to bind up. And it seems that this assembly was designed to be protected from water somewhat by the slip clutch shield, which like a lot of shields on old equipment was gone on this baler. There's no seal to really prevent moisture from getting into this clutch, either from being left outside, (like this baler was at the dealers) or from high humidity. They should've had a better cover at least for this. Hopefully this saves me about $500. They wanted around $350 just for the sprag clutch, but I found a whole new assembly for around $450 from the UK, I'm sure shipping would be $50 or more.

It's nice to be able to fix something for once.
 
I am very reluctant to tear into things at times. It seems to blow up on me and can't get it back together or something jumps out and runs away. Good for you. Learned something new, now if you can just remember it a couple years from now. lol gobble
 
My big problem is taking something apart, and starting something else before I finish the first project... Then I have to remember how it came apart, and where all the various parts walked off to...
 


Congratulations on your tenacity. It sounds like you have that dreaded disease "must-fix-it-itis"
 
Didn't have much choice but to fix it. A new sprag, and I mean JUST the sprag, was $350ish. Found the whole new slip clutch assembly for $450 from the UK, but shipping was going to be another $400+. I still need to get a few bales of straw to run through it to make sure it ties ok. I don't have much hay to bale, but if it ever stops raining, I need to be ready to go.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top