MF 135 UK Lift Arms Pulsing when raised

bmacd11

Member
I've been rebuilding a 1972 MF 135 UK with my brother and while we're mechanically inclined, this is our first tractor. We've muddled through power steering, brakes, ring & pinion, control spring overhaul, etc. but we're having problems with hydraulics now. The oil in the old tractor was bad (milky) so we replaced that along with the filter. We also replaced lift piston rings. The linkage is our downfall. When we got the tractor a while back, the Position Control wouldn't work at all but we could move the lift arms with Draft Control. We took the lift cover off to get at the filter and to change the bushings in the lift arms; and to clean it all up, including partial disassembly of the quadrant. We have none of the special tools to set-up the lift cover so we put it back on hoping for the best. I did notice before installing that moving the Position Control lever did nothing. On the first re-install we bent the position linkage. Reading some posts, we fixed the that problem (roller had dropped off the end of the cam and bent the linkage mechanism under pressure). We put the lift cover back on and the position control works great now except..... the lift arms are pulsing in time with the pump as the arms are being raised and when holding a position. No pulsing when the arms are being lowered which would make sense since there's no pressure.
We're just about to remove the lift cover again to see what's up, so any advice on what to chase would be great.
BTW, now that the position control is working, the draft control doesn't seem to do anything. As soon as you move the lever, it sends the control lever to discharge position (and I mean all the way forward). There is no in between at all. Just goes forward and stays there.

Thanks for looking into my dilemma.
 
Before you take the cover off again try running the arms up and down 20-30 times with weight on the back. You may just have air in the system. Did you do anything with the pump other than change the filter? Often times studdering like that can be sticking valve in the pump. With the right side cover off and tractor off try working the pump arm back and forth the full range of motion a few times. That "may" jar it loose if that is indeed the issue.
You will need to do those linkage adjustments for things to function properly. You can improvise the tools and get it done but you will need the manual for proper procedure.
http://www.agcopubs.com/ has the massey manuals. If you are in the UK there might be another source, not sure.
 
(quoted from post at 19:37:56 01/31/18) Before you take the cover off again try running the arms up and down 20-30 times with weight on the back. You may just have air in the system. Did you do anything with the pump other than change the filter? Often times studdering like that can be sticking valve in the pump. With the right side cover off and tractor off try working the pump arm back and forth the full range of motion a few times. That "may" jar it loose if that is indeed the issue.
You will need to do those linkage adjustments for things to function properly. You can improvise the tools and get it done but you will need the manual for proper procedure.
http://www.agcopubs.com/ has the massey manuals. If you are in the UK there might be another source, not sure.

I'm in Eastern Canada actually. I do have the Massey Manuals that stipulate all the lift cover adjustments. I know there are alternatives for the special tools, but I don't have specs on all of them. Is there a publication that would indicate how to mimic the 'special tools'? I haven't read the adjustment paragraphs for awhile so I can't remember exactly all the tools. I do have this from another forum:

MFN 124 = 11/64 feeler gauge ( .17")

MFN 163 = 3/8" thick piece of flat steel

MFN 970 = anything that will hold the dash pot plunger fully extended.

I will try your suggestion tomorrow and let you know how it works. It's strange to me that we didn't have this pulsing before. I know the trouble shooting guide points towards sticky valves but why would they start sticking all of a sudden. I has been drained for a few months now while we got parts and worked on the other issues. Maybe some water stayed in the pump and caused corrosion.
Here's hoping for an air lock :)

Thanks.
 
Leaving it drained can cause issues. The valve is a precision fit and any corrosion will cause headaches. I left mine drained for a year while i rebuilt the front half of the tractor. Had the same issues when i got it running again and working the pump lever by hand did the trick.
 
Hi, a sticking poppet valve in the pump is the likely cause of the
pulsing when you raise the linkage. Think of a 4-cylinder car running
on 3 cylinders. That is a comparison. Presumably you have removed the
quadrant from the cover. Are you sure that you have engaged the rollers
correctly? It is very easy to make an error during reassembly or
refitment. If you have straightened the linkage is it running freely
and EXACTLY as it was before?
As to the special tools - they are essential for the system to work
correctly and to avoid any risk of breaking the cover. The pump MUST go
into neutral with the linkage at the correct position. There is no
alternative that I am aware of in the UK and have not come across
anything in my 40-plus years of MF experience. Do you have an MF dealer
or someone who has the special tools anywhere near you that could set
the cover up correctly for you? There are adjustments that need to be
done after the cover is fitted. These are just as important as the ones
before.
DavidP, South Wales
 
Now I'm frustrated! I just entered a long dissertation with photos and then lost it because it signed me off for taking too long.

Anyway, here I go again. I tried working the pump control valve back and forth several times and that didn't help. We weren't able to lift a load because the back wheels are still off from the brake job and ring gear. So, we're leaving that issue for later and we'll do the heavy lifts before over-hauling the pump. I suppose we could just carry on with a stuck valve for awhile? It's annoying but it works.

Moving on: while trying to educate myself on why the draft control just seems to push the plunger into discharge and nothing else. I thought maybe someone before us had removed the quadrant and messed up the rollers on the inside. I did see a picture on another post that showed one roller forward and one roller aft as being correct but that doesn't seem right to me and it's not what I see in the diagrams in the book unless I'm reading them wrong. They are confusing. Anyway, while I was playing with the draft control lever (I took it off and installed it in the other direction; still didn't work right) the position control cam dropped out again. I heard it click and then had no response on the position control lever. So, we took off the lift cover again to fix the cam which was no problem. But, then we noticed that when the arms are fully raised, the position control link rod didn't reach it's hole in bracket. This is worrisome because if it misses the hole under pressure, it will certainly bend or break the linkage. We had the lift arm re-surfaced when we first got into this because the linkage roller had gouged into the arm. As I said earlier, this lift cover had problems when we bought it and the position control wasn't working. Anyway, it seems to me now that the problem could be that the roller is worn so bad that it's not pushing the rod far enough forward. possible? I'm attaching pictures of the rod, the ones of the roller didn't come out well but it is just a little smaller than ones I've seen for sale on eBay.

We tried setting up the LC as per the manual, but we just aren't seeing the results that we should, I don't think. As I said, the draft control is just not acting like it's supposed to. The position control seems fine except for the rod as mentioned. So, we've decided to take the lift cover to MF and have them look at it. They will know if we need new parts or not, hopefully.

This tractor has 3000 hours on it and from what I can tell, it was rode hard and put away wet. I don't think preventative maintenance was was in the previous owner's vocabulary. Some days are diamonds.....
mvphoto9984.jpg


mvphoto9985.jpg
 
When you say you had the lift arm resurfaced... did they weld up the groove and bring back to spec or did they mill the whole thing down to the groove depth? If they just milled it down then its hosed.

Where are the control levers at in the picture? are both up or down? In the first pic lower left corner it appears the small coil spring is not hooked up and just dangling there. Is that that case?
 
(quoted from post at 23:59:01 02/01/18) When you say you had the lift arm resurfaced... did they weld up the groove and bring back to spec or did they mill the whole thing down to the groove depth? If they just milled it down then its hosed.

Where are the control levers at in the picture? are both up or down? In the first pic lower left corner it appears the small coil spring is not hooked up and just dangling there. Is that that case?

No, they built it up; we had no spec so they just filled the groove and then leveled it. That's a good point. If they did grind it down any at all, it might explain the short fall. The small spring may be unhooked; I forget when I took the picture in the process. It did come unhooked when the lift cam dropped out of position and it dropped out a couple of times when we were working the problem.
 

So, do you think I should get metal added to the lift arm or get a new link. I think a new roller would be bigger diameter but maybe not enough to extend the rod into the hole.
 

As for position for the pic, both levers are up and the ams are full up. It wouldn't take much to get the rod started in the hole which is all it needs to prevent misalignment when the arms move down. What would be the normal position of the rod in the hole in this configuration? Should it be just started into the hole, all the way seated in the hole or the rod tip actually through the hole to some extent?
 
Both should be sticking through the bracket. The bottom one is way out of adjustment. There is a bolt that runs through a couple holders on the bracket and into a special adapter connected to the linkage. Just outside of view to the left on your picture there. It is actually hooked up right? Sometimes that gets forgotten and nothing will work right.
 
(quoted from post at 11:30:26 02/02/18) Both should be sticking through the bracket. The bottom one is way out of adjustment. There is a bolt that runs through a couple holders on the bracket and into a special adapter connected to the linkage. Just outside of view to the left on your picture there. It is actually hooked up right? Sometimes that gets forgotten and nothing will work right.

Yes, that bolt is hooked up. I played with it a bit to see if I could move the rod further through the hole but any adjustment on the bolt and on the cam adjustment screw had little effect; some but not enough. I'm wondering if the draft position is way out and having some effect. As I mentioned earlier, When you move the draft lever out of it's parked position, it drives the control valve into discharge position immediately and that where it stays through the entire movement of draft lever from up to full down. This action was stopping me from being able to do the final adjustments when the lift cover was on the tractor. It seems to me that before (when the lift cam fallen down out of proper position) that the draft lever travel had more movement on the the control valve end. I'll go take some more pics to give you a better idea of what's happening. I can't travel to the MF dealer today anyway because we're in the middle of a snow storm.
 
At this point it's probably best to wait and see what the dealer has to say. It sounds like things are just way out of adjustment.
 
(quoted from post at 12:00:10 02/02/18) At this point it's probably best to wait and see what the dealer has to say. It sounds like things are just way out of adjustment.

Can you replace the valves on the pump without disturbing the pistions and other parts? The parts diagram leads me to believe you can do that. Just looking for things to do while we wait for the lift cover.
 
Just an update to my situation. I ordered a new position linkage and low and behold, the rod on the new one is about 3/4 inch longer than the one in tractor. This will solve the misalignment with its hole issue I'm pretty sure (don't have it all back together yet). While I was looking for a solution on why the lift cam keeps dropping behind its roller on the position lever shaft, I noted that the part number now provides a cam that is shaped different from the one in my tractor. The new one has a point added to the rear of the cam which will prevent the cam from falling out of place. The original doesn't have that point on it. I'm pretty sure that's the case anyway. Still waiting for the cam to come in the mail. In the meantime, we've changed the valves on the pump; hopefully that will stop the pulsing.
My big question: I'm confused on the position of the main position/draft shaft rollers. My position and draft rollers are both positioned toward the front of the lift cover on their respective shafts. I saw a post from DavidP that said the draft roller should be facing toward the rear of the lift cover. Does anyone have a picture of the correct position of the two rollers? I haven't changed anything, and the draft was working correctly before we took it apart, I believe. Both my rollers are toward the front.
 
(quoted from post at 14:11:19 03/05/18)
Has anyone yet made a video on the lift cover adjustments. I've searched on uTube for days and can't find anything on the lift cover. Lots of talk around taking it off and putting it on but next thing, it's installed and working. What??

The MF book is not bad but certainly a little confusing; and it doesn't show how to fix an incorrect positioning of roller or links. Maybe it's my copy, but the pictures are terrible.

Appreciate your help.
 
(quoted from post at 21:57:23 03/08/18)
(quoted from post at 14:11:19 03/05/18)
Has anyone yet made a video on the lift cover adjustments. I've searched on uTube for days and can't find anything on the lift cover. Lots of talk around taking it off and putting it on but next thing, it's installed and working. What??

The MF book is not bad but certainly a little confusing; and it doesn't show how to fix an incorrect positioning of roller or links. Maybe it's my copy, but the pictures are terrible.

Appreciate your help.

Well, finally got it done. Two things changed to help out with the position problem. First, the new position cam is a different shape which doesn't allow it to drop out of position. Photo attached.
Second, The new position link is different from original in that the rod is about 3/4 inch longer which prevents it from misaligning with the hole it goes into.
Additionally, we installed new valves which remedied the pulsing action when lift arms are raised.
Never did take it to the dealer since I was pretty convinced the changes in part configuration would solve my problems, which it did.
We got the lift cover set up almost as per the manual. The draft lever tension is more than 3 lbs when it's set up but everything else is correct including the synchronization setting. So, since we don't use draft control anyway, we'll just leave it as is.

Thanks for your help everyone and I consider the issue closed. Tractor lift arms work as they should.

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