MF 135 hydraulic pump not pumping

fredviktor

New User
My 135 has never had any issues with the hydraulics before now. I did not use the tractor this winter and when starting in the spring the hydraulics was dead.
I thought it might be water in the oil and it had caused something to freeze and crack during the winter. I have removed the lift cover but cannot find anything obviously wrong.

The strainer was quite full of "gunk" as well as the bottom of the oil sump. Clearly there has been quite a bit of over greasing and the oil has not been changed any time my father could remember!
The strainer had some holes and there was a bit of gunk inside the strainer as well.

I have filled the sump with oil to cover the "strainer seat" and then some. But the hydraulic pump is not pumping any oil when I start the engine. There is a slight buildup of air pressure when I put my finger over the output hole on the pump, but nothing near a "hydraulic pressure".

I made a video of starting up the engine after I "filled" the output hole in the pump with a bit of oil manually. You can see the air "blow" the oil out, but no new oil is being pumped.

Am I doing something wrong or is the pump not working?
Can I do anything more with this without removing the pump?

This is the video:
https://vid.me/e/zQFJ
 
It probably got some crud in the pump making it not work. Did you check the linkage to see how it was working before you removed the lift cover?
 
Sounds like a stuck control valve.....remove the valve from the pump and free it up....Did you remember to remove the roller before lifting the lid??? You were very lucky there was no oil pressure when you put you finger over the hole or you may have
lost your finger if not more...hydraulic oil can penetrate your skin under pressure and get into the blood stream....be careful!..........Sam
 
(quoted from post at 00:46:24 05/30/16) It probably got some crud in the pump making it not work. Did you check the linkage to see how it was working before you removed the lift cover?

I think crud in the pump is quite likely. It might have settled during the winter, making it not work now...
I did not look at how it was working before I removed the top cover :(
 
(quoted from post at 03:18:56 05/30/16) Sounds like a stuck control valve.....remove the valve from the pump and free it up....Did you remember to remove the roller before lifting the lid??? You were very lucky there was no oil pressure when you put you finger over the hole or you may have
lost your finger if not more...hydraulic oil can penetrate your skin under pressure and get into the blood stream....be careful!..........Sam

The contol valve rod(going into the pump body) is moving out when I move the roller forward. Can the valve be stuck inside anyways?
Will I be able to remove it without taking out the hole pump? Seems really tight down there...
I did not remove the roller before removing the lift cover:(. It didn't seem to break anything, but I used som time to put it back together with the pump with the small pin and other parts...
 
The pump is not difficult to remove and it will be easier to work at.....Remove the 3 bolts around the PTO shaft retainer ring...and withdraw the shaft....fit a drive shaft to help with leverage if it is tight..Now remove the split pin through the main drive shaft
shear tube, but mark which hole you take it out of....Then remove the two dowels from each side of the transmission housing (1/2 inch wrench)...The pump will now be free to wriggle backwards and lift up out....It is tight and there is a way of lifting it but
persevere you will manage....Now you can wash out the complete sump and remove the control valve for cleaning.......Sam
 

Thanks for the advice!
It sounds a lot easier than it looks :)
Some busy days coming up, but I'll go ahead removing the pump this weekend.
It allso sounds good to be able to clean out the sump!
 
(quoted from post at 14:55:59 05/30/16) The pump is not difficult to remove and it will be easier to work at.....Remove the 3 bolts around the PTO shaft retainer ring...and withdraw the shaft....fit a drive shaft to help with leverage if it is tight..Now remove the split pin through the main drive shaft
shear tube, but mark which hole you take it out of....Then remove the two dowels from each side of the transmission housing (1/2 inch wrench)...The pump will now be free to wriggle backwards and lift up out....It is tight and there is a way of lifting it but
persevere you will manage....Now you can wash out the complete sump and remove the control valve for cleaning.......Sam

I removed the pump yesterday. No issues.
When removing the control valve cover there was some crud inside the valve housing, but not a lot.
When I pull the valve "pin" the valve does not come out. The pin is spring loaded and I don't dare to pull too hard on it.

Shuld the valve come out easily?

36509.jpg
 
You also have to take the pump apart. You have to anyways because some other parts of the pump will need to be looked at since that crud got ran through it. It's best to get a manual if you want to learn to do it yourself, or find someone who has with experience do it.
 
Okay.
This will most likely be a one time job, but I have no problem buying a manual and going at it myself.

Do you know anyone that sells a digital copy available for download?
I've googled, but came up empty handed...

Got the valve out yesterday, but not sure if more parts shuld come out easily. Allso I found a couple of small peices of metal inside valve housing... Not good.

36602.jpg
 

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