MF50 front end loader is erratic

jswordy

New User
Happy Thanksgiving!

Long saga here and I'm wondering which way to go now. My MF50's hydraulic system does just fine to raise, lower and hold up a Woods mower mounted in back. There's nothing wrong with the lift-arm end of things at all, so I am thinking the pump end of things is good.

But, my old MF loader on occasion (and with increasing frequency) will not pick up or if it does pick up, even at higher rpm it will not generate enough pressure to raise a round bale of hay. If I rev the engine and play around with it awhile (or maybe just get lucky), sometimes all of a sudden it will "catch" and lift the bale like it should.

Once it "catches," it tends to work OK on the following lifts then. Store the tractor and shut it off, and the next time I'm likely to have the same problem.

There are a couple of loader symptoms, that one being the first. The second, which I think is probably unrelated, is a slight leak down of the loader. With a load on it, it does very gradually leak down so I have to tap the lever to bump it up from time to time. I figure that is probably normal leak-by from wear on the pistons and barrels of this old valve, and it mainly is just a nuisance but not a big deal. But couldn't it also be leakage of the standpipe O-rings?

The two-way loader is run by a remote two-spool control valve that's fed through a one-port push-pull diverter valve fastened to the transfer cover. When the valve is in one position, the rear arms work. In the other oil is diverted to the loader.

I have already R&Red the remote loader valve (a 45-year-old Cross) and replaced the O-rings and a broken bypass spring, using Cross parts (those folks were great to work with). I bought the loader used about 20 years ago, so the bypass spring may have been broken all this time, I don't know. When I finished rebuilding the valve, the loader at that time worked fine.

So I was happy and put the tractor away a couple weeks, and then here we go again. :roll:

About 5 years ago, the lifting cylinders were rebuilt. Once installed, they worked great.

So, my questions:

1.) My MF50 is a 1963 (SN SGM 536788). Does it have a hydraulic filter? I know the early ones did not, and there is no mention in my original MF owners manual nor an I&T Shop Service manual of servicing a filter. (But then, neither one mentions the power steering filter, either!) But then I figure if the filter was bad the back end would not work well, too.

2.) Could this be cause by a collapsed supply hose, either the one going to the remote valve or from the valve to the cylinder lines? I'm thinking it could be similar to a brake line or fuel line that internally collapses and affects the pressure. I had this experience with a rubber fuel line on other equipment just recently. It worked fine cold, but closed off when hot.

3.) I had suspected maybe the relief valve on the pump, but if it were that, I'd think I should have trouble with the back end too. Thoughts?

4.) Could this be somehow related to the push-pull valve on the transfer cover? I know the standpipes sometimes leak, but I would think that symptom would not let the system suddenly "catch" and then work fine awhile.

5.) Could it mean the cylinders need to be rebuilt again? If so, why do they "catch" and work?

6.) Should I remove the line to the remote valve and run it in a bucket to verify flow?

The oil in the system is recently changed 90 weight, as specified for this tractor. I changed the oil when I did the loader valve.

I have owned this tractor 24 years, it is the primary tractor for my cattle farm, and it has been beautifully reliable up until now. Unfortunately, it is now hay-feeding season and a problem I thought I had fixed is back again.

Thanks for all help and troubleshooting direction.
 
i would say your oil is to thick
9o wt gear oil is not for hydraulics
i would use universal hydraulic oil it's thinner
on my 73 mf29 tlb its all i use in it now for 25
yrs
 
(quoted from post at 13:56:53 11/27/14) i would say your oil is to thick
9o wt gear oil is not for hydraulics
i would use universal hydraulic oil it's thinner
on my 73 mf29 tlb its all i use in it now for 25
yrs

Thanks but this tractor uses 90 weight gear oil. That's what was in it when I drained it. The hydraulics and the transmission are integral and not separate systems.
 
Don't know that much about diverters but if the back
lift works and the fel doesn't and if it's not due
to cold weather and thick oil I'd suspect that. I'd
look for a front pump or pto pump for the fel.
 
90 weight gear oil and 90 weight mineral oil are two
different things. I use universal hydraulic oil in
my 65s. A lot of guys use motor oil. The topic has
come up on here a bunch of times. Look in the
archives.
 
It should use Massey Ferguson Perma-Tran oil, or universal tractor transmission/hydraulic fluid that meets MF spec M1129. On another note if you drain half of the oil out of the transmission, and pull the cover off where the pto control lever is, and look inside. You should be able to see the strainer if it has one (since it's a 63 year model I think it should have one). Since it uses the internal pump the loader will be slow since it only pumps about 4 or 5 gpm. I would look into the bypass valve on the hydraulic pump while it will raise a shredder a heavy round bale on front of the loader is another story. Does it act up when you work the loader without anything heavy on it?
 
My 1960 MF 65 takes 90 wt Mineral oil, sold at napa...not 90 wt gear oil....I get from your post that your using the tractor hydraulics to run the loader and not a separate pump, same as mine....90 wt gear oil is Waaaaayyyyyyyyyyyyyyy to thick
 
forgot to add that I chain down my 3 pt to use the loader, not sure of what kind of system you use, that could be the problem too
 
(quoted from post at 00:25:23 11/28/14) It should use Massey Ferguson Perma-Tran oil, or universal tractor transmission/hydraulic fluid that meets MF spec M1129. On another note if you drain half of the oil out of the transmission, and pull the cover off where the pto control lever is, and look inside. You should be able to see the strainer if it has one (since it's a 63 year model I think it should have one). Since it uses the internal pump the loader will be slow since it only pumps about 4 or 5 gpm. I would look into the bypass valve on the hydraulic pump while it will raise a shredder a heavy round bale on front of the loader is another story. Does it act up when you work the loader without anything heavy on it?

Thanks for the info on oil. Yep, the manual calls for 90 wt. mineral oil. The oil that came out of it was quite thick but looked fine. The thing is, this all was happening BEFORE the oil was changed. Thanks for the tips on what to look for. To answer your question, sometimes the loader will not raise. Sometimes the loader will raise but it will not pick up a bale. The back always works fine.

bugaloo, on this system all toy have to do is set the hydralever and draft control all the way up to use auxiliary cylinders. Again, from the manual. Worked fine for me before.
 
Thanks to all for the info on oil and spec.

It did have this problem before the oil was
changed, though. Maybe the old oil got too thick.
It looked OK draining but was not runny like so
many hydraulic fluids I have seen.

The 3-point will pick up a bale on a spear, no
worries. If I top out the lift arms, I can hear
the relief valve squeal.

So I'm still thinking there's something else up front.

I'll drain the oil, pull the cover and check the
screen as soon as I get my current repair out of
the shop.

Just in case, where is the relief valve located on
the pump and it it replaceable through the
inspection covers?

bugaloo, on this tractor, all I have to do (per
manual) is to pull the hydralever and draft lever
all the way back, and the loader operates.

The loader was quite quick for 20-some years. It
can't keep up with modern equipment, but it was
fast enough.

I'll search the site some more. Did that quite a
bit before posting.
 
How old are all the hoses for the loader? Could have pieces coming off from inside the hose(s) and they run through the system making it work erratically. If you don't have a shop manual for the tractor, get one, it will show where to hookup a pressure gauge so you can see what the pressure does when it acts up. That will really help with trouble shooting the hydraulics. You can also go to http://www.agcopartsbooks.com/PartsBooksN/login.aspx?region=NorthAmerica log in as guest user then enter the model number, and search. You can look at the pump in the parts book so you can get a better idea of what you are working with as far the pump (or anything else) goes. [/list]
 
More info. Went out to feed hay today and the
loader will lift itself but not the bale. So I
dropped the bale spear with the front cylinders,
then raised the loader arms, then dropped the bale
spear, raised arms, dropped spear, etc.

This way, the bale stays on the ground but the
loader arms can lift themselves. Then I raised the
bale spear with the front cylinders and that's how
I got the bale up off the ground to move it.

The arms hold the bale up just fine once it is off
the ground using this method. They will not raise
it farther, though.

This isolates the problem to the arm cylinders
only, it seems to me. They can't be leaking
internally, my reasoning goes, or they would not
hold the bale up once it is up. Same with the
loader valve plunger.

What I think I'm going to find is:

1.) A hydraulic line between the valve and the
loader arm cylinders that is collapsed or
restricted internally, or

2.) a filter in the sump that clogged. I think in
this case, the shorter cylinders and the 3-point
work because they require less volume than the
long loader arm cylinders and the pump can;t keep
up, or

3.) Both. It could be the cylinder restriction cut
down flow gradually to where debris that would
have been swept out accumulated somewhere in the
lines.

I'll check for a filter first. Found a pic onsite
of where it should be.

I gotta tell you this system using the tractor
pump has performed fabulously for over 20 years.
It's a MF branded loader that I bought used back
then. The guy had it on a Ford using it the same
way. I intended to get the model off the plate,
but forgot. It's moved thousands of bales of hay
quick enough for me.

I'll get pix and report what I find when I do get
into it. I just don't want to go at it without a
plan because it can't be down for long.

BTW, I have a fiver of TSC hydraulic oil that is
universal and says it meets MF-1129A. Is that the
stuff? Sure is runny!

If that's it, I'll pick up another. Thanks to
everyone again.
 
The TSC universal transmission/hydraulic oil that meets MF-1129A is what we use here, no problems with the Texas heat, or when it gets cold. We use it in a MF 135, MF 150, MF 2135 industrial, New Holland 6640, Ford 7710, and a Bobcat 743B skid steer with no problems. You have to remember the oil sold these days has come a long ways compared to the oil that was available when these tractors were built. I'd bet even the 90wt mineral oil that's sold these days is different in some ways than it was back then.
 
When using front loader your draft and position control levers for 3 point hitch need to be all the way up.Have a mssey 65 that had a loader that ran off of tractor hydraulics.With pump flow diverted to front loader I had to make sure draft and position control levers were up all the way.Hope this helps.
 
(quoted from post at 11:16:47 11/30/14) When using front loader your draft and position control levers for 3 point hitch need to be all the way up.Have a mssey 65 that had a loader that ran off of tractor hydraulics.With pump flow diverted to front loader I had to make sure draft and position control levers were up all the way.Hope this helps.

Thanks, I know about the control positions because I have the original owners manual. It's funny though, mine worked just fine with draft all the way up or all the way down. Found that out by error. (And the draft does work.)

My prior repair shop project was completed Sunday. Went out to get the tractor out of the barn to put it in the shop. It was 65 here Sunday (nice!). Anyway, the loader picked right up and acted right from the get-go.

Everything looks good so far for the badly clogged filter theory.

Drained the oil. It was grayish color coming out. Checked for chunks of anything. None. I left it opened up and dripping into pans. If things work out, I should start working to get the inspection cover off tonight. It's calving season for me, so who knows?

I assume from reading the service manual that the whole PTO cover just comes right off as an assembly.

I'll get pix of what I find. I'm going to bet the sumps will need flushing. Thanks to all for helping me out.
 
Just in from the shop, cleaned up and enjoying a beer. Promised you a picture.

Ummm, I think I've found what was sending chunks through my loader. Blew out the lines and cylinder fittings - a nice messy job. Hope I've got it fairly well cleaned out. Now to find a new filter.



It probably had a much smaller hole in it to start, then let completely go the other day with the thicker oil. That's why things worked so well! Danged hard to get in there with the loader frame on.

I'll check NAPA for a filter first. If they have it, I can pick it up tomorrow while in town. If anybody knows the number in NAPA, Wix or Baldwin, I'd appreciate it.

Thank you again for all your help! Boy, this beer tastes good... :lol:
 
Wix, and NAPA use the same number W03AT354
Baldwin PT9516

These are (should be) stainless mesh, rather than the plastic mesh like your old one was, so it shouldn't do what your old one did.
 
Thanks. The old one was wire mesh with a paper overlay. There's an AGCO VPK1520 that's a cross for this app, and that's the one with the paper overlay (at least according to the pix I saw).

Interesting, none of Wix, NAPA (which is made by Wix) or Baldwin online cross references would cross to a number. I wish I'd seen your message earlier. I ordered a mesh one through TSC. Be here in 3-4 days. I'll write your numbers in my book in case I need one in the future.

Under edit: Glad I went with TSC, worth the wait. NAPA, $60; Wix, $49; Baldwin, $38. TSC Tisco 521451M1, $13.99 plus tax, free ship to store.
 
When NAPA, and Wix, put their names on a filter some of them get pricey. Just about all of Baldwin filters are over priced. The Tisco should be just a stainless mesh (I prefer those over the others).
 
I just wanted to follow up to say the new screen-type filter
(Made in the UK) is in with the correct fluid and
I'm lifting bales again.

Went out to feed and found lightning had knocked out
both my solar fencers. Next repair! It never ends on
the farm.

Thanks again for all your invaluable help.
 

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