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.
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.