# MF255 Steering Question



## BonesD (Apr 5, 2017)

Hello, I am new to the Forum and new to tractor ownership. I recently bought an 81 MF model 255. The power steering comes and goes. Mostly goes. I pulled the plug on the pump and it seems full. I don't know if there is another inspection point or not
I picked the front end off the ground and steering is smooth a little effort with the engine running. Engine off it is stiff as would be expected. There are two steering pistons and both show no sign of leakage and pistons are nice and shiny when extended. 
I guess the pump is not working or is bleeding internally. Has anyone got hints for me for diagnosis before I order a new pump?
I will appreciate any input. 
Thank you


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## TraderMark (Nov 15, 2011)

Welcome BonesD.
There are several things that can cause hard steering. Let's start with the easiest ones first.
Grease both spindles. Lack of grease in the bushings inside the "knees" where the spindle shafts pass through can cause hard steering. Give the fitting in each knee a couple shots of grease, then steer left and right and repeat a couple of times. Grease it until you see grease starting to ooze around the top or bottom of each knee where the spindle sjaft slides through.

There's a thrust washer at the bottom of each knee. The flat part of the spindle shaft rides against this thrust washer. If the washer is worn badly, you should see a gap between the steering arm attached to the top of the spindle shaft and the top of the knee. Replace the thrust washers if there's any up and down movement of the spindle shaft when you lift the front axle with a jack.

According to the Agco website your tractor may or may not have a filter inside the power steering pump reservoir. You may be able to tell by shining a light into the filler hole. If there is a filter, you'll need to remove the reservoir to change the filter. Pumps that do not have a paper filter element have a metal screen strainer. To clean the strainer the reservoir will need to be removed as well.

The steering cylinders can be bypassing internally. They may not be leaking externally but oil could be passing by a blown seal on the piston inside the cylinder and cause hard steering.

Try greasing the spindles, tie rod ends and anything else connected with the steering first, change the filter or clean the screen whichever your case may be, then post back and get into to the more detailed things.

HTH,
Mark


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## BonesD (Apr 5, 2017)

Mark, thank you for the quick reply and for sharing your knowledge. 
I will tackle it like you have suggested. Its a great old tractor. I think I will need to rewire all the lights and ignition. 
Thanks again.


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## pogobill (Jan 31, 2012)

Pop over to the introductions forum ( http://www.tractorforum.com/f158/) and start a thread to tell us a little about yourself and that tractor of yours. We'd be interested to see that MF 255 and have a look at what problem you are dealing with.
I've been having trouble with my power steering as well, but due to lack of time, I've disconnected the power steering cylinder for now. I'll have to look into it later, I'm afraid.


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## BonesD (Apr 5, 2017)

I lifted the front wheels and if I am looking at the correct part "knees", then the right hand side has no bushing and the left does. When the wheels are on the ground there is no space between the two parts on the right but a little light shows through on the left side but there is definitely a bushing there. One of the attached photos shows me pointing with a screwdriver.
Oddly though, while moving the tractor this morning the steering was working well. I agree that there is a bushing problem I don't know that it would cause intermittent ease of function?
Pogo Bill, I included a picture of the old beast.


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## TraderMark (Nov 15, 2011)

You can go to http://www.agcopartsbooks.com and click on the "View Books" button in the Guest User box, then type in your model and make to view a complete parts catalog for your tractor.

I'll attach an exploded view to try and clear up what My words are inadequate to describe but keep in mind the drawing is NOT a Massey, it's a pretty generic drawing but close enough.

Item 32 is what some people call the "knee". The vertical part of the knee has a bushing in the top and bottom.
Item 41 is the spindle. The vertical shaft of the spindle passes through the bushings in the vertical part of the knee. Lack of grease can cause the vertical spindle shaft to bind against the bushings in the vertical part of the knee and cause hard steering.
Item 39 is the thrust washer/bearing. If this washer/bearing is worn the spindle can bind against the bottom of the knee and cause hard steering.

If you have everything all greased up and still have hard steering it may be something in the hydraulics that's causing your problem.

Mark


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## BonesD (Apr 5, 2017)

Mark thank you for the info and the diagram. I have a shop & parts manual that show the assembly well. Since I cannot see a bushing on the right side that must be causing a lot of drag. My book calls it 196-167-M1, Thrust Bearing.
so I guess I will order a pair of those. I see a seal located in the top side of the spindle and a bushing top and bottom I imagine are wear points, probably change those also. I wonder if the bushings are pressed into the spindle housing? 
Is there anything else in the area that should be addressed? 
Now if I can just figure out what to block this thing up on while working on it.
Thanks


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## BonesD (Apr 5, 2017)

I ordered a set of bushing kits so now I am trying to remove the spindle from the housing. I spread the clamp at the top and by hammering the top of the spindle and down next to the hub I have been able to drop the spindle about a 1/4 inch and there it seems to have stopped. Has anyone hints for getting the spindle out besides a bigger hammer. 
Thanks for looking.


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## BonesD (Apr 5, 2017)

I will answer my own question. Just loosening and spreading the top clamp is not enough The clamp bolt must be removed as it keys in the top of the spindle. Also the key in keyway doesn't just rock out with pressure from the spindle It must be removed by hand. After that the spindle falls free easily.


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## shona13 (Aug 12, 2011)

G'day bonesD.

There are thrust Bearings on the bottom of the front axle,s ,a bronze coated bush top and bottom of the axle housing 
If the axles come out as easy as you mentioned there is nothing there that would cause the steering to be difficult to turn, ! Mechanically that is . the steering box does not often cause problems but with the linkage rods disconnected turn the steering wheel lock to lock and make sure everything is nice and smooth,no tight spots or grinding,if all ok.
remove the power steering pump reservoir, clean/replace the filter, fill with ATF Dexron 2 or whatever your local oil supplier has.
If this does not work you will have to remove the pump.
Happy days.
Hutch.


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## BonesD (Apr 5, 2017)

Thanks for the info. The side I am working on is missing the thrust washer on the bottom. I don't know if wore completely away or someone neglected to install it. I see that one of the models actually has a ball bearing assembly that goes in the same place as my thrust washer. The left side is correct. I don't know that this will correct the problem or not but I'm sure it will help.


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## shona13 (Aug 12, 2011)

G'day.
If you have both front stub axles out it is a good time to degrease and thoroughly clean all old grease and !!!!!!!!!!! from the grease void between the top and bottom bushes,don't forget to pump some fresh grease through the grease nipple to get rid of any old grease
Repack with as much of your favorite colour grease before reassembling with, as little a mess is good ,also good to think of these things prior to you doing them and ending up well.
I think I see a loader on the tractor !generally any agricultural tractor with a front loader attachment suffers terribly by being constantly overloaded consequently axles,bearings, trunnion etc all over time feel the effects ,with this in mind It pays to over grease the whole Machine daily when you plan to use the loader ,apart from making a bit of a mess, make your own mind up where the balance is between over greasing and keeping the abrasive dust and sands that may cause premature wear at bay.

If you go along the axle bush replacement road you may have to be prepared to have the installed bushes line reamed or have an adjustable parallel reamer on hand to finish ream the assembly, keeps everything nice and snug, It is sometimes not improper installation of the bushes either but the axle housing has been made wrong or has been damaged/bent in a past life ,this is why you need to ream the assembly.
Replace the wheel bearings with Good Quality Bearings ,it might cost a bit more but trust me it will cost you more than lost production when you need it but it will also ruin friendships.
Any way just shout if you need advise it's free.
Hutch.


The reference I make To " agricultural tractor with a front loader attachment suffers terribly by being constantly overloaded" I am of course referring to Tractors originally designed as agricultural tractors and in a general manner My old Dad always said if
it 's Workin don't touch it .


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## BonesD (Apr 5, 2017)

Thanks Hutch for the good advice. Keeping things greased is better than tearing down for repair.


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## BonesD (Apr 5, 2017)

Well, I just got the correct parts. The Thrust Washer seems to be tapered, like if you took a cone and sliced it into a thin washer. I can feel up in the bottom of the Arm Assembly that is slightly recessed. I'm guessing the smaller side of the washer faces up into the recess. the other side goes down against the spindle and shaft assembly It just rides on the flat so I imagine it doesn't matter on that side.
I'm just guessing. Anyone familiar with this? Thanks


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## Agman55 (Nov 14, 2019)

Im in the process of buying a 79 MF 255 with the 236 loader, this thread has some great info.......I just hope its a LONG time before I have to do anything more than keep the front end greased!


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