Need some help with my old MF40B

   / Need some help with my old MF40B #1  


New member
Dec 5, 2014
grand rapids
MF 40b
i have an old MF40b thats sat for years, and its time to get it running again. when i parked it, it had a fuel leak and there was no steering input. the steering wheel just free wheels and nothing happens at the front wheels.

looking at an old post i made about it, it looks like someone said that it may just be out of power steering fluid? so a couple of questions on that - do i fill through the big neck on the PS housing? or the little bolt on the PS itself? fluid level? im not finding a dipstick for it. and what kind of fluid for it? im seeing a whole mix of responses on what type of fluid?

im also replacing the fuel filter and ive taken all the lines off the unit already, along with removing the gas tank to clean it out. ive seen mud that was cleaner than the crap that came out of the filter... anyways, im assuming illl need to bleed the injectors? do i crack open the lines next to the injector, or the bolt on the top of the injectors?

which brings me to my next questions. when i took the fuel lines out, a bushing was attached to one of them, and pulled passed the flare on the other line and is stuck in the housing still. what are these bushings called? and can i just slip new ones over the existing flares or will i need to cut the ends of the line off, install the new bushing, and reflare?


  • IMG_2104.JPG
    3 MB · Views: 66
  • IMG_2105.JPG
    3.6 MB · Views: 63
  • IMG_2107.JPG
    4 MB · Views: 64
   / Need some help with my old MF40B #2  
Hydraulic oil is sufficient for vf the PS filled through the "bolt" pictured. Fill to edge and check level after running a minute. Trans/hydraulic oil is fine too.

The bushing needs to be removed from the housing. If it is rubber, replace it and others at this time.

Bleed injectors at large fitting on injectors. Small fitting on top is just bleed off line
   / Need some help with my old MF40B #3  


  • MF40B fuel.jpg
    MF40B fuel.jpg
    484.6 KB · Views: 51
   / Need some help with my old MF40B #4  
*Check reservoir on steering pump to make sure it is full.
*See if you can turn wheels by spinning steering wheel with engine off (lots of turns, hard work)
*Take the output line off of the pump and plug in the pressure gauge. Start the tractor and rev it up. The pressure should be 1500PSI.

*Next remove the lines on one of the cylinders. Cap the return line and plug the gauge into the pressure line. (the pressure line is the line that would cause the cylinder to extend.) Start the tractor and turn the wheel while watching the gauge. You should see decent pressure.
*Reconnect the lines and work the wheels back and forth to get all the air out of the system. Check pump reservoir to make sure it is full.
*Go to the other side and repeat. You should see the same pressures on both cylinders.

*If you get low pressure dead heading the pump then you know the pump is bad.
*If you get different pressures between the steering cylinders then you know that one of them needs repacked.
*If you get low pressure with both cylinders then we need to determine what to look for next.