MF 135 Loader Hydraulics weak and slow

[tankerfarmboy]

On both of my MF35s the rear hydraulic arms will settle overnight. That is something that they have always done. My 202 Workbull reacts similar to your tractor with the FEL. My problem was the hydraulic spool valve. I have an auxillary pump on the front and my hydraulics would creep down rather quick. Changed the spool valve and it now works great.

 

[stapleford]

After we removed and cleaned the filter as has been said previous, and changed the gearbox oil, the speed of the loader doubled, and it will lift a 1 ton bag of sand, which is enough to bring the back wheels off the ground if there is no block on
ignore the rear link arms dropping which doesn稚 affect the FEL as this is just oil; leaking from the rear lift cylinder back into the gearbox. You can replace the piston and or rings or even the complete cylinder (about ｣55 or $100 ) if it is an issue but all older tractors I have driven suffer from this whcn stopped
However the slow loader issue is more likely the flow of oil
It can also of course be worn or stuck relief valve (need to put a gauge on the hydraulics to test max pressure) or as said before spool valve
The loader cannot drop with engine off unless the oil leaks out the lift ram to atmosphere through the piston or stem seal, or the pool valve is leaking allowing oil to leak back through and back down the return into the gearbox (so no visible leak)
Our loader will drop about 3 inches over a few hours only
I also found that the draft lever and valve from the top link was upsetting the loader oil supply under certain conditions until we serviced it, also moving the supply pip on the centre valve to the right hand port form the left means that it works independent of the rear in terms of not lifting the link arms up first before supplying full pressure due to the way the porting works. Great if you have a topper on and don稚 want it to be lifted too high and damage the PTO every time you max out the loader bucket rams
Nige

 

[TexasChris]

After we removed and cleaned the filter as has been said previous, and changed the gearbox oil, the speed of the loader doubled, and it will lift a 1 ton bag of sand, which is enough to bring the back wheels off the ground if there is no block on
ignore the rear link arms dropping which doesn稚 affect the FEL as this is just oil; leaking from the rear lift cylinder back into the gearbox. You can replace the piston and or rings or even the complete cylinder (about ｣55 or $100 ) if it is an issue but all older tractors I have driven suffer from this whcn stopped
However the slow loader issue is more likely the flow of oil
It can also of course be worn or stuck relief valve (need to put a gauge on the hydraulics to test max pressure) or as said before spool valve
The loader cannot drop with engine off unless the oil leaks out the lift ram to atmosphere through the piston or stem seal, or the pool valve is leaking allowing oil to leak back through and back down the return into the gearbox (so no visible leak)
Our loader will drop about 3 inches over a few hours only
I also found that the draft lever and valve from the top link was upsetting the loader oil supply under certain conditions until we serviced it, also moving the supply pip on the centre valve to the right hand port form the left means that it works independent of the rear in terms of not lifting the link arms up first before supplying full pressure due to the way the porting works. Great if you have a topper on and don稚 want it to be lifted too high and damage the PTO every time you max out the loader bucket rams
Nige

Wow that just completely confused me!
Chris

 

[MrFar]

The FEL will just barely lift a bucket of soil but only if I rev it to well over 1500. Any less and it just sits there. It picked up a rock about 2 1/2 feet in diameter that I am guessing weighed about 3 to 400lbs but just. I will clean out the filter and try to locate a pressure/flow testing setup. Can I test at the remote connection?

 

[MrFar]

Here is what I was told by the mechanic. If the cylinders have 2 lines take the upper one off and raise the loader slightly(watch out for spray). If fluid comes out, the cylinder is bypassing and needs to be rebuilt. If the loader has down pressure also, raise the wheels and let go of the control. If it sinks back to the ground quickly this is another clue that the cylinder is bypassing. I checked mine and both are pouring oil out the cylinders with the upper lines off when I raise the loader. Off to the machine shop with them.

 

[bill50cal]

what he told you is wrong with double action cylinders. you will push oil out because it has oil in both sides. if it leaks down when you lift the front with the bucket it could be several things not just the cylinders.

Here is what I was told by the mechanic. If the cylinders have 2 lines take the upper one off and raise the loader slightly(watch out for spray). If fluid comes out, the cylinder is bypassing and needs to be rebuilt. If the loader has down pressure also, raise the wheels and let go of the control. If it sinks back to the ground quickly this is another clue that the cylinder is bypassing. I checked mine and both are pouring oil out the cylinders with the upper lines off when I raise the loader. Off to the machine shop with them.

 

[MrFar]

Sounds logical. Is it possible then to do this test with the bucket loaded with something that it is not lifting thereby not pushing any oil out due to the movement? The curl cylinder has no problem moving heavy stuff.

 

[bill50cal]

the best way to find out is wrong is to run a pressure test. you will need a couple of gauge's with a 3,000 PSI range and some adapters. that way you will have more info and not just guessing and throwing expensive parts at the problem. IF you have a very strong curl and a weak lift than you COULD have a cylinder that is bypassing but I am not going to say that IS where your trouble is at.

Sounds logical. Is it possible then to do this test with the bucket loaded with something that it is not lifting thereby not pushing any oil out due to the movement? The curl cylinder has no problem moving heavy stuff.

 

[MrFar]

I tested the pressure using a 3500 psi gauge that I picked up for under 20$ with adaptors. It shows 1800psi at 1200 rpm right at the control valves output with the lines disconnected to both the cylinders. Looking like a cylinder problem, and fortunately there is a machine shop nearby that specializes in cylinder rebuilds.

 

[J_J]

Tractor data says you should have about 2800 psi, and about 4.5 GPM.

http://www.tractordata.com/farm-tractors/000/7/4/743-massey-ferguson-135.html

What you don't know, is if the pump is good, or the relief valve setting.

If you are reading about 1800 psi, then the pump is not producing the posted specs, or something is bleeding off the fluid, could be cyl seals, valve spools, or a relief valve, or weak pump.

A flow meter and pressure would help in your trouble shooting.

What kind of pressure do you have on your 3pt.

You do a hyd test at the IN port of the FEL valve, then the pressure gage will indicate psi whenever a lever is actuated.