ManitouMB26JC forklift mast problem

[Manitoumb26jc]

I managed to sort out the non working power steering on my 1980s forklift by cracking a joint after the pump that bled some air out and hey presto steering is back but now another issue is the mast is going up ok but will only come down to about three or four feet from the floor and stops there every time it comes down in exactly the same position
The forklift was out of action for a long while due to clutch replacement so I am wondering if this could be a stuck valve
Not sure how the mast actually works other than it’s hydraulic. I have checked the side rollers which are free and greased everything but wondering if there is s valve that allows the forks to come down that last few feet ?
Any ideas are most welcome

[Jeremy Rowland]

Bob, it could be a safety valve or a spool valve issue or a mechanical issue, if you have another forklift or way of supporting the mast, I would slack off the hydraulic feed and return pipes with the mast held by the other machine, and then see if you can lower it down with the other machine, if it comes down, you know its a hydraulic problem, if it does not then its a ram of mast issue.

Jeremy

[Manitoumb26jc]

Hi
Thanks for your reply
I don’t have another machine to support the forks, I just added weight to tge forks with concrete blocks but no different
Its got two masts, no electronics as its 1980s vintage
Larger mast at the top with piston facing up seems to operate fine but the smaller mast below with piston facing down doesn’t seem to be moving at all
The lower mast has one hydraulic connection that comes from a vessel described as an accumulator on the parts manual that connects at the end of the piston
If this lower mast isnt being fed pressure will there be a valve somewhere or is it this accumulator that allows pressure in to this hydraulic line ?

[Jeremy Rowland]

Hi
Thanks for your reply
I don’t have another machine to support the forks, I just added weight to tge forks with concrete blocks but no different
Its got two masts, no electronics as its 1980s vintage
Larger mast at the top with piston facing up seems to operate fine but the smaller mast below with piston facing down doesn’t seem to be moving at all
The lower mast has one hydraulic connection that comes from a vessel described as an accumulator on the parts manual that connects at the end of the piston
If this lower mast isnt being fed pressure will there be a valve somewhere or is it this accumulator that allows pressure in to this hydraulic line ?

Very carefully slacken the hose to the accumulator off, if the mast lowers slowly as the hydraulic fluid leaks out then you know the issue is hydraulic not mechanical, but as I say be very careful!
Jeremy

[Manitoumb26jc]

I loosened the hose going to the accumulator and wyite a bit of foamy milky fluid came out but absolutely no movement of the mast so I reconnected that and put 40 concrete blocks on the forks then took it up and down three of four times then it came down at last so it must be the mast sliders or bearing/guides jamming I assume

[Jeremy Rowland]

I loosened the hose going to the accumulator and wyite a bit of foamy milky fluid came out but absolutely no movement of the mast so I reconnected that and put 40 concrete blocks on the forks then took it up and down three of four times then it came down at last so it must be the mast sliders or bearing/guides jamming I assume

Okay make sure that the mast is clean and free of rust, put plenty of oil and grease on it, then work it up and down, like you initially said it could be that it has tightened up due to corrosion as it had stood for sometime.

Jeremy