MF 31 Sickle Mower Refurbish

[Creamer]

This is simple. Since you are talking about ledger plates i am assuming that you have the older, thicker mower style guards and not the newer haybine type. these are more difficult to adjust than the newer ones but it can be done.

Assuming your cutter bar and sickle bar are straight:
1st - it sounds like you have different styles of guards mixed on the cutter bar. Try to get the same styles grouped so you do not have a lot of transitions.
2nd - Install the wear plates behind the sickle in the most retracted position possible. Then check for contact of the wearplate with the sickle in the fore/aft direction and adjust so that they are all just touching the sickle bar. You should replace any wearplates that are worn more than halfway through. You can push this limit some but you do not want a wearplate to give out while you are cutting.
3rd - check guard to bottom of section clearance (assuming you have decent sections and that they are not bent). Adjust the guards up or down - any guard including the cast ones because I do not know of any that are not - using a hammer and hitting near the tip of the guard. You can also use a pipe over the end of the guard. I can never remember breaking a guard this way unless it was previously cracked. The sickle should lie flat on the ledger plates - if not you have guard style issue but most are interchangeable.
4th - adjust the holddowns via tapping with a hammer so that they are just touching the top of the sickle sections.
5th - verify your sickle moves easily. I am not familiar with the MF machine but you can turn a pulley or take the drive loose and move the sickle by hand. You should not have to pound on it.
6th - start the tractor and run the sickle and watch and listen - watching for for aft movement and any jerkiness and listening for rattle. shut the tractor off and check for any catch points or heat build-up. You should not be able to see the sickle catching and anywhere and it may be a little warm but certainly touchable. If it is hot you have it constrained to tightly and would not have passed #5
7th - lubricate the sickle with used oil at all the wear plates and hold downs. I prefer using a Dawn Dishwashing detergent type squeeze bottle which gives me control and keep my hands away from the sickle. Now when you run it you should hear much less noise.

You should be ready to go.

Basically you have ti give the sickle a straight path to run in and constrain it so it does not bounce around. Then make sure you have not overconstrained it and make sure you maintain the scissor like action between the section and the ledger plate. Personally I have never seen ledger plates wear out. i have seen them rusted beyond any degree of sharpness and need to be replaced and other types of damage but it has had to have lots of use to have been worn out. Last year I bought a sickle bar mower from the 60s that had been used on a dairy farm for 30 years and then not run since but stored inside and the ledger plates are in fine shape.

Good luck!

 

[Optiker]

Try this link for your parts book:

http://www.agcopartsbooks.com/PartsBooksN/Viewer/book.aspx?book=agco/651025

If that doesn't work for you, go to Agco Parts Books, click on the View Books button next to the Guest User heading, and then search for your 31 mower in the Massey Ferguson brand section. You'll have to page down on the results page to get to it, but it is there, even if some of the parts themselves are NLA. Good luck!

The first link didn't work, but the one to Agco Parts did. Thanks very much!
Optiker

 

[Kioti Tom]

Go to Amazon.com and look up MF31 manuals. the Parts manual comes up as
one of the manuals.
Tom

 

[Optiker]

Personally I have never seen ledger plates wear out.

See the pictures. These are both currently reinstalled on the mower. The shiny one isn't rusted because I took it off when the mower broke last time a few years ago and had it in the barn. The rusted one stayed on the mower, outside, but under a shed roof. You can see on the shiny one the worn groves trailing away from the notches in the serrated edge. The other one is just so badly worn that there is no longer serrations in the middle of the cutting edge.

Incidentally, notice the gap between the ledger plates and the sections. That's probably the worst, while with some guards, the section is actually contacting the ledger plate. I'm about to go out and try to align everything!



Optiker

 

[Optiker]

I thought I'd send along a picture showing the variation in the various guards, including one which I am guessing is an original, since it's the only one with a bevel to match the underside leading edge of the bar, one stamped MF, which I assume was installed later, but has no bevel, and one that is a generic that I took off my NI30, hoping it would fit. The thing to notice is that the measurement between the flat that contacts the underside of the bar when the guard is installed and the top surface of the ledger plate is different for each of the three. For the two that aren't the original, the smaller measurement means that the ledger plate surface is well below the bottom surface of the sections - probably too much to adjust.

Also notice that only the original one has the bevel. The middle one - the one stamped MF that has no bevel - was on the mower when I got it, and I used it that way until the mower finally broke. I suspect that too-big gap was a part of the jamming problem.

FWIW!



Optiker

 

[Creamer]

See the pictures. These are both currently reinstalled on the mower. The shiny one isn't rusted because I took it off when the mower broke last time a few years ago and had it in the barn. The rusted one stayed on the mower, outside, but under a shed roof. You can see on the shiny one the worn groves trailing away from the notches in the serrated edge. The other one is just so badly worn that there is no longer serrations in the middle of the cutting edge.

Incidentally, notice the gap between the ledger plates and the sections. That's probably the worst, while with some guards, the section is actually contacting the ledger plate. I'm about to go out and try to align everything!

View attachment 373882 View attachment 373883

Having nice sharp edges would be nice but the real issue with ledger plates is the crown, i.e. higher in the middle than on the edges which creates a gap between the sickle section and the plate. Gap is what typically causes the crown as the grass drags across the edge wearing it down. The vertical gap between the section and plate is a big issue.

BTW - you can take a grinder and grind the edge of the ledger plate vertically to remove the serrations but put a sharp edge for better cutting on it. The haybine style guards have no ledger plates or serrations and cut just fine. I grew up cutting a lot of tough native "prairie" hay with them in the Dakotas. The serrations are not necessary. Today's tame hays are much easier to cut.

 

[Creamer]

I thought I'd send along a picture showing the variation in the various guards, including one which I am guessing is an original, since it's the only one with a bevel to match the underside leading edge of the bar, one stamped MF, which I assume was installed later, but has no bevel, and one that is a generic that I took off my NI30, hoping it would fit. The thing to notice is that the measurement between the flat that contacts the underside of the bar when the guard is installed and the top surface of the ledger plate is different for each of the three. For the two that aren't the original, the smaller measurement means that the ledger plate surface is well below the bottom surface of the sections - probably too much to adjust.

Also notice that only the original one has the bevel. The middle one - the one stamped MF that has no bevel - was on the mower when I got it, and I used it that way until the mower finally broke. I suspect that too-big gap was a part of the jamming problem.

FWIW!

View attachment 373886

Optiker

I am missing what you are trying to show me in these photos.

The distance from the actual bar to the back of the guard is not an issue as long as the sickle has a straight path to run in. If the sickle has a straight path and it is properly constrained the rest should not matter.

One thing I did forget to mention in my list is to check the lead. The outside end of the sickle bar should be about 3" ahead of the head end when everything is setting on mice level ground (assuming you have a 7-9' sickle bar). This is because the whole mower twists slightly as drags on the ground in the dynamic world of mowing and so the lead is just compensation for the drag.

 

[Optiker]

BTW - you can take a grinder and grind the edge of the ledger plate vertically to remove the serrations but put a sharp edge for better cutting on it. The haybine style guards have no ledger plates or serrations and cut just fine. I grew up cutting a lot of tough native "prairie" hay with them in the Dakotas. The serrations are not necessary. Today's tame hays are much easier to cut.

Hadn't thought of grinding off the serrations. That might be a good alternative to new ledger plates. I found a source of them in small quantities at only @$1.25, so cost isn't an issue, but time to do it is, and I haven't found rivets yet. I can order those by the pound, even though I just need a few. I've also been told numerous times that smooth sections rather than serrated are recommended for grass. My intuition is contrary to that, but so be it. Nevertheless, all of my sections are serrated.

The gap is definitely an issue. I'll work at that today.

Also, I have an opportunity to buy a JD 350, and when I looked at it, it had no ledger plates...first time I ever heard of that.

Thanks!
Optiker

 

[Optiker]

I am missing what you are trying to show me in these photos.

The distance from the actual bar to the back of the guard is not an issue as long as the sickle has a straight path to run in. If the sickle has a straight path and it is properly constrained the rest should not matter.

One thing I did forget to mention in my list is to check the lead. The outside end of the sickle bar should be about 3" ahead of the head end when everything is setting on mice level ground (assuming you have a 7-9' sickle bar). This is because the whole mower twists slightly as drags on the ground in the dynamic world of mowing and so the lead is just compensation for the drag.

The issue here is the vertical distance, when the guard is installed, between the plane of the top of the ledger plate and the bottom of the bar - the bottom of the bar being the surface of the guard (shown in the pictures) that is in contact with the bar when it is installed. Imagine taking a guard that is properly installed and shimmed so that the gap between the ledger plate and the bottom of the section is as it should be. Now, imagine putting an 1/8" shim between the guard and the bottom of the bar and tightening it down. That would result in an 1/8" gap between the bottom of the section and the ledger plate. That's effectively what happens when I install the "generic" guard since that measurement is only about 1/2" compared to the "original" guard at 5/8". It has nothing to do with the distance from the back of the bar to the back of the guard.

I haven't checked lead yet, but eyeballing, it looks pretty good. Yes, it is a 7' bar.

Thanks!
Optiker

 

[Sodo]

The issue here is the vertical distance

Agreed

Is this pic "in use"? Or is it partially disassembled?

I can't imagine how that could do ANYTHING but fold the weeds in half and jam them into the guard. The shearing edge of the section needs to slide directly on the guard below, to create the shearing action.

What is causing the section to rise so far above the guard? Is the sickle 'track' full of weeds, lifting it up? Is the bar bent? Is there a block that rides ontop of the sicklebar keeping each cutter section down low against the shearing edge (that you may grind sharp) of the guard?