1540 lost hydraulics

RyanL · Mar 31, 2007

Hi, i have a 1540 and have lost hydraulic power. I have been using this tractor to move alot of dirt the last few days, and went to get it out today and it would barely pick the loader up at idle. I checked they pressure on it and at 1000rpm it will spike up to 1100psi and leak back off as your holding the valve. At 2200 rpm it has 3500psi ( yes i have turned the relief up, and i would rather not hear critism about, please i have used it this way for a yr and half now) The hydraulic work fine with the rpm up but at idle there is no power, if you pick the 3-point and loader up at same time the 3-point will stop. The fluid level is the right. I think it might have gotten a couple gallons of straight 10 wt hyd. oil added to it. The dealer said it is still under waranty, and said to bring it in, said could be pump or relief. I am going out to see what it does with warm oil. yes it has been acting funny last few days.

Thanks, RyanL

JerryG · Mar 31, 2007

Sounds like your 3500 PSI has blow a seal or valve out. I hope that you don't expect them to warranty it.

RyanL · Apr 1, 2007

Yes i think maybe a seal. And i am going to see if they warranty it or not, if they do well then thats great, if they don't well then i will bring it back home and put new part on out my pocket, if my doing caused the problem then i will fix, i take responsible for my actions. But the 1500series does have some down falls i think, and one is the hydraulics, but still one stought tractor though.

JerryG · Apr 1, 2007

RyanL said:
Yes i think maybe a seal. And i am going to see if they warranty it or not, if they do well then thats great, if they don't well then i will bring it back home and put new part on out my pocket, if my doing caused the problem then i will fix, i take responsible for my actions. But the 1500series does have some down falls i think, and one is the hydraulics, but still one stought tractor though.

If that is true, you might as well take your check book with you. I can tell you by the way it is acting that the high pressure is what caused the problem. A person can turn the system up 10% or so and not have any problems but turning it up in the neighborhood of 1300 PSI will blow the system. I am actually surprised that you haven't blown some hoses or had other leaks before now.

RyanL · Apr 1, 2007

Yes, it was a mistake on my part i didn't mean to turn the pressure up that much. I did check it with a gauge after turning it up. If it won't be covered under warranty then i am doing the work myself. I ain't trying to point a finger i am just trying to narrow down the problem.

JerryG · Apr 2, 2007

I am guessing that the 1533/40 are adjusted the same way as the 1433/40. If they are, I hate the way you have to get to the thing. It looks like they could have come up with a easier place for the relief than they did. I would be willing to bet that there are even several dealers that have needed to adjust the pressure and when they got it anywhere in the ball park, they didn't bother trying to get it closer. It's location is the very reason that I haven't adjusted mine differently.
BTW, When they work on it. Please let up know exactly which part went out. I would like to know what the weak link is. Given the amount of pressure difference, it is amazing that it went that long. Like was said it is one tough tractor. How many hours did you put on it during that time span?

RyanL · Apr 2, 2007

Well i ain't sure about the 1400 series but i adjusted the relief that is on the tractor mounted joystick. And now that you mentioned it when the dealer came and checked the pressure when i bought it said it was little low not much. I used it to mow yard tonight with 6ft rear mower and the hydraulics seem to work fine at higher RPM's but you hear the relief all the time. I have always heard the relief on this tractor even before messed with pressure. At idle the hydraulics don't have much power (1100 psi @ 1000 RPM) but if you rapidly move the joystick from netral to raise you can get them it to go up little at time. I woundn't think there could be whole lot wrong with pump if it will work at higher RPM.

I wander if the pump is rebuildable, if that is the problem. I am going to wait till after easter to take it.

Also wandering if anyone has gotten a repair manual for on of these yet?

Thanks, Ryan

JerryG · Apr 2, 2007

Ryan,
Did you put a gauge on the system to see the pressure (3500) or did someone tell you that was the pressure?

RyanL · Apr 2, 2007

Yes i personaly put a gauge on the system both cold and warm oil and at 2000rpm it has 3600psi.

JerryG · Apr 2, 2007

Ryan,
Well. You definitely have a problem. To start with, you shouldn’t have been able to get 3600 pounds of pressure by adjusting the relief on the loader. If you were able to get it to that pressure by adjusting the relief there, then the system relief is too high. If they haven’t changed it, the system relief is on the side of the transmission below the seat. It is on the backside of a hydraulic manifold that has more than likely has two lines and two hoses going to it. The entire system is set by this relief. The relief at the loader is what I would call a step down relief. It in essence reduces the system pressure down to what is needed at the loader. Most tractors have it set up like this so that the three point hitch will have more pressure that the loader does. If you still have the gauge, set the pressure on the loader back to the pressure that it was originally or 2150 PSI. Do this with the engine at 2600 RPM and the valve handle all the way up or down. If you can’t you will need a new relief valve for the loader. I really think that you will have to have a new relief. Fluid has been flowing through the relief ever since you jacked it way up and it more than likely ruined the valve. What is think you have done is you have blown the loader relief. More than likely the rest of the system is OK or I hope that it is. If it isn't, the pump and or the system relief could also be blown.

At idle you shouldn’t have very much pressure. Even 1100 PSI sounds high at idle. The only time, the pressure should be high is when work is being done. You can hold the control valve to the end of the stroke either way and it will give you the relief setting pressure. This is how the max pressure should have been checked.

When working with hydraulics it is dangerous to guess at what you are doing. It is always better to at least ask someone that knows or get a good manual and study it.

Get you a set of manuals from your MF dealer. They are the best on the market and they are much less expensive than any of the other name brands.