MF 135 hydraulics

Hello everyone, and thank you in advance for any help given.

I recently purchased a 1968 MF135 gasoline tractor (4 cyl) at an auction. I paid $1000 for it, so I'm not in too bad a shape at this point. I was aware that I couldn't get the hydraulic lift arms to work at all ( they are stuck down, but I can lift them by hand, they just fall right back down.) It has an independent PTO (which works perfectly)and the multi shift tranny (which also works just fine,) the only thing wrong on the tractor is the hydraulics.

I started off by draining the hydraulic fluid (it was way over filled, but was pretty clean and caramel colored, but not milky.) filled it back up and still nothing from the lift arms.

So I got ahold of a shop manual, and after searching this site, I'm not sure what to do next. I thought about changing filter, but I don't want to pull the PTO shifter cover off because I'm pretty sure there is a tube connected to it. I have no problem pulling the whole hydraulic cover off if I can access what is wrong from there. Splitting the tractor if it has to come to that is a little out of my league. I'm pretty mechanically inclined, but that scares me.

Any advice would be greatly appreciated.

Thanks,
Jeremy

Take the round cover off on the right side where the dip stick for rear end is and see if the little roller is still on the arm.
you will need to drain the oil down to the bottom of the cover first. you can start up the tractor and move the lever to see if the arms
lift.

You will NOT be able to clean the filters thru the left cover with the linkage. The lift cover has to come off to access them. There are two filters. Main Hyd and IPTO pump filter. Also, the control spool in the main pump my be stuck. Before pulling the lift cover, drain oil to bottom bolts of right cover, remove cover, remove linkage roller. I use tag wire on the roller so I don't drop it into the belly of the beast. Remove seat and use those two holes for lift attachment. Don't remove the four nuts under the seat, they hold the lift cylinder.

Picture of my 150 is attached.

Ok thank you both for the responses. I work a 9-5 job so I won't be
able to pull the top cover off til the weekend. However, I did have time
tonight to pull the cover off the right side. Im definitely not a tractor
expert but something doesn't look right with the linkage. One pic is
with both the position and draft up and the other with them both
down. With them both up there is pressure applied on the roller but it
does not move the linkage, and with both down there is no pressure
at all.

Is this normal? I drained all of the oil, as I just bought it was easier...

I will pull the top this weekend unless there is something that
someone sees in the pictures that is not normal.

if you re moving the levers and the arms move but don't move the vertical control arm with the roller on it your valve is stuck in the pump. we've done many of these and you will have to remove the pump from the machine. if you have IPTO that means splitting the tractor otherwise you can get pump out by removing the lift cover. once out you will need to dismantle the pump to free up valve. this is common in machines that haven't had their oil changed frequently enough,or oil with water. ythis isn't a job for an inexperienced mechanic