Replaced MF50 clutch, hard to operate

EricG1793

New User
Hi everyone,

I've replaced the clutch in my 1958 MF50 (serial begins in 518) because it was grinding gears. However, I have a bigger issue now. The clutch is so hard to push that I have to stand on it, and if I try to push it all the way down the floor board, the pedal will slip out of adjustment no matter how tight the retaining bolts are. The movement seems fine, and the tractor moves fine (though still grinds gears, probably because I can't push it down far enough). The clutch assembly came from the local tractor shop that does a lot of work on all brands of antique tractors, so I trusted that they'd be able to get a good, correct part for me. But I'm not so sure.

I know that there's an Industrial and an Agricultural MF50 (mine's Agricultural), and there are red springs and yellow springs. Am I right in thinking that my clutch should have yellow springs? The one that's on it now has red springs, which I didn't think much of considering it was an aftermarket part.

I've been asking the shop that sold me the clutch assembly about it for a few weeks. They're starting to wonder if the clutch should be 6 springs or 12 springs; perhaps I got a 12 when there should only be 6. They reached out to the supplier, who said that that's the only clutch for the MF50. So they reached out to another supplier that isn't returning their calls.

From what I gather in the Agco Parts Books for that tractor, there should be 12 yellow springs. Does anyone know for sure?

Only other thing I can think of is that the fingers are severely out of adjustment. But my understanding is that they just need to be adjusted equally, not necessarily to a specific distance. I did make sure they were equal and had to adjust 1 of the 3. But I wouldn't think that that would make the clutch hard to push. There's also a chance that the wrong throwout bearing is wrong (not the shop's fault), but again, I don't see how that would cause this issue.

Any insight would be appreciated!

- Eric
 
(quoted from post at 14:29:20 12/15/17) Hi everyone,

I've replaced the clutch in my 1958 MF50 (serial begins in 518) because it was grinding gears. However, I have a bigger issue now. The clutch is so hard to push that I have to stand on it, and if I try to push it all the way down the floor board, the pedal will slip out of adjustment no matter how tight the retaining bolts are. The movement seems fine, and the tractor moves fine (though still grinds gears, probably because I can't push it down far enough). The clutch assembly came from the local tractor shop that does a lot of work on all brands of antique tractors, so I trusted that they'd be able to get a good, correct part for me. But I'm not so sure.

I know that there's an Industrial and an Agricultural MF50 (mine's Agricultural), and there are red springs and yellow springs. Am I right in thinking that my clutch should have yellow springs? The one that's on it now has red springs, which I didn't think much of considering it was an aftermarket part.

I've been asking the shop that sold me the clutch assembly about it for a few weeks. They're starting to wonder if the clutch should be 6 springs or 12 springs; perhaps I got a 12 when there should only be 6. They reached out to the supplier, who said that that's the only clutch for the MF50. So they reached out to another supplier that isn't returning their calls.

From what I gather in the Agco Parts Books for that tractor, there should be 12 yellow springs. Does anyone know for sure?

Only other thing I can think of is that the fingers are severely out of adjustment. But my understanding is that they just need to be adjusted equally, not necessarily to a specific distance. I did make sure they were equal and had to adjust 1 of the 3. But I wouldn't think that that would make the clutch hard to push. There's also a chance that the wrong throwout bearing is wrong (not the shop's fault), but again, I don't see how that would cause this issue.

Any insight would be appreciated!

- Eric

I am a complete novice at all these repair issues so I purchased and downloaded a video from Vintage Tractor Engineer. The video I have is on a MF 35 clutch and the original had 12 yellow springs. The mechanic explained that the new replacements were red and since they were stronger, thicker springs only 6 were required. Could be the same thing on your 50? Don't take my word for it,as I really don't know what I am doing. (I usually have to do a job twice to get it right)
 
I have never worked on a MF 50 Clutch, however, I have owned a MF 35 X since new and have always referred to a MF SERVICE Manual for info as well as the Parts Book:

Hope these pics are of assistance:

Bob...
a250454.jpg

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a250461.jpg

a250462.jpg

a250463.jpg
 
I'd suspect extra heavy spring pressure too. All MF clutches I've had apart use twelve springs for the main disc apply pressure, but vary the spring test pressure depending on what engine power the clutch needs to hold. Same thing for the PTO Belleville tension spring, think there are at least three different thickness of those also. For example, a 275 MF set of twelve springs would be overkill for a 135 clutch. I seldom replace clutch springs, unless the spring tester shows they are weak on clutches I have apart.
 
Thanks to everyone who pointed out that there should indeed be 12 yellow springs. I'm thinking that's the culprit. So, if we can't get the shop to exchange the assembly, I see where I can just replace the springs. I was hoping to not have to take the assembly apart, but how difficult is that?

Phil, regarding backwards disc: That possibility came up during the install, so we paid attention to the shape of the center of the disc and how it falls in to place within the rest of the assembly. If I remember, if it were backwards, it would have been rubbing against something else. I don't think that's the issue, but I'll check when it's apart.

Bob: Thank you for all those pictures and the annotations! I do have the service manual; the cap screws were removed (they had to be, or else the main disc would fall out of alignment and the tractor couldn't be joined).

What is the "Belleville color mark" that is supposed to be red? Is that the PTO Belleville tension spring that Dieseltech mentioned? Where is that located?
 
Quote:

What is the "Belleville color mark" that is supposed to be red? Is that the PTO Belleville tension spring that Dieseltech mentioned? Where is that located?

EricG1793...If you require the pictures and procedure to dismantle the clutch assembly let me know and I shall post here on "YT"



Pics:

Bob....
a250485.jpg

a250486.jpg
 
Assembly will need to come apart to change any springs for each clutch disc. Three Tee handle 1/4 inch homemade allthread tools, release lever pins then need each groove lock pin removed before the lever pins will come out. I've been thinking about it, the pedal linkage on MF 50 is similar to later tractors, and should be about the same pedal pressure and NOT slip the clamp on the shaft. Have you removed the bottom plate and made sure something else is maybe causing the sudden hard pedal, causing the clamp to slip? Have all three PTO release bolts been set to .080 inch? Does the main disc release at all? I'd look in there first with a helper on the pedal..
 
Thanks gain for the pics, Bob. So the Belleville spring is inside the clutch assembly; I won't worry about whether THAT'S the right part, then. I assume that the PTO release bolts are adjusting the tension of the Belleville spring, correct? I did not check these but will before reassembling, but wouldn't they only affect the tension of the 2nd stage? It's both stages that have gotten very difficult.

Confirmed, the main disc was not in backwards. If it were, its center would be pressed up against the flywheel bolts rather than the disc against the flywheel surface. Everything was operating fine, except the pedal pressure.

I've attached pictures of everything as it was before removal. We've since removed the clutch assembly and will take it to the shop this week to try to get the spring situation sorted out.
 
The AGCO parts book shows to use clutch part number 512355M91 (which should have yellow springs). The yellow springs are AGCO part number 1753746M1 (Sparex part number S.01781). The original part number for your clutch is AGCO 184541M94.
 
Not only did they have different color springs, they also 12, or 6 spring clutches (they even made them with a 12, or 6 with yellow springs).

You got a 12 spring, take 6 of them out.
7745.jpg
 
The PTO RELEASE bolts have nothing to do with PTO tension, that's built into the Bellville spring. If the first stage pushes hard it's most likely the wrong MAIN clutch springs. What the .080 clearance means is the main pressure plate is pulled away by the release levers by .080 inch, THEN the bolts contact the PTO pressure plate and further travel will then release it too. I'd be curious to know what pressure springs tested in the original clutch, and what you have now. Only way to know for sure is with a spring tester and compare. Sounds like you may have the really heavy MF 275 dual clutch springs, those had to hold the A4.248 Perkins engine, and would be overkill on anything a Continental 134 or Perkins AD3.152 could dish out.
 
ptfarmer: Thanks for those part numbers. I'll keep those in mind if I end up needing to deal with the mistake myself, as opposed to the tractor shop correcting the issue. (Again, their supplier says that this clutch assembly is the only option for an MF50.)

I won't be able to test the old springs; I don't have a spring tester, and the old clutch assembly has been scrapped by the shop (how convenient).

Speaking of spring tension, I'm concerned about just taking out 6 of the springs. There are supposed to be (12) yellow springs at 80-88 lbs; let's say 84. That's 1,008 lbs total.

The service manual (pictured by Bob above but with the MF65 "lavender" springs on the right cut off) says the lavender springs are 111-123 lbs; so with 6 of them at 117 lbs, that's 702 lbs.

That's a pretty big difference; should I be worried about the clutch slipping? Come to think of it, the tractor originally seemed to have a stiff clutch, at least compared to an 8N, Deere 310 backhoe, and Ford 5000, so a bit lighter of a clutch would be great for ease of use, but not if it slips (hoping to use it for pulls at some point).
 
My 135 has 12 yellow springs, it will either bury the tractor to the rear axle if you let the tires spin, or kill the engine if they can't spin (Perkins ad3.152 diesel).
 
My dad just got off the phone with the tractor shop, and they asked if we set the step of the flywheel correctly. I don't know what that means, any ideas?
 
To follow up on this, the tractor shop ended up exchanging the clutch assembly for one with 6 springs instead of 12. The clutch now feels like it has the right amount of tension and operates well. (Whether it continues to grind gears after warming up, I have yet to find out, since the front end is apart due to radiator replacement.) It's a bit lighter than it was originally, which is fine with me since it seemed a little heavy even then.

Thanks for the information, everyone!
 

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