its electrical. there is a circuit board under the computer, which can corrode and break continuity. You will need to take the left step off to access the problem. The big black box houses the computer, disconnect and remove the computer. The white plastic circuit board is underneath. you will need to remove it. then carefully seperate the halves to access the corrosion. take pics to reassemble properly when done. You will find the break, likely need to solder in a jumper wire from to bridge the gap created by the corrosion. Take you time and lots of pics, it should go fine.
Again, there's a manual release valve to lower the forks. Located ontop of valve body. Use this to indicate a mechanical or electrical problem. If the mast won't lower this way, mechanical. Any dents in free lift cylinder tube? You stated it drifts enough to lower it. Possibly the valve located in the center of the free lift rod stuck closed due to rust. Never had one drift that much unless a seal, tube issue. Outside secondary cylinder tubes rust and pit due to lack of use. Repair is replacement only. Tubes are bad and won't hold a seal. Mast would drift down only. I believe this issue you have is electrical since you stated it drifts down. Lift circuit solenoids. Try and Loosen just enough the main lift hose to see if it lowers upon release of oil. Oil out and lowers. It's Electrical! Won't lower. Mechanical, cylinder, bearing shims, thrust bearing, mast channel debris etc.
It is your lift/lower solenoid, check voltage when lowering mast.
solenoid is on bottomside valve block, the one nearest to the steering.
On front side valve there is a M6 screw, lift mast and unscrew the m6 a little bit, when it will lower mast the solenoid is broken, do a complete valve section repair and watch out for the little spring that comes out when you loosen the 2 inbuss boults.
John
You can loosen the main lift hose just enough to check mechanical side of the mast to see if it lowers. If it lowers then you cleared up the mast. Next is electrical. Lift/lower solenoid on valve body. Have to measure coil resistance and or replace/check the lift switch located on main valve body. If oil hasn't been maintained, the screen fills up with ash from dirty oil and causes this.
check forks and fork support for (even) (Proper alinement).... We had a similar issues with a Mitsubishi lift - Forks would go up - would come down and then stop.... Would only go down about knee high....
We adjusted the chains - Chain was tight on one side - causing the fork support to bind and pull to one side... Hope this helps.
Still have not solved. The mast at it raises but nothing else and no codes.
Thank you for your response. It's not the bearings. It still only raises. Eventually it goes down but only because it leaks down very slowly. If I raise it 2 inches it would take 30 min to slowly leak down all the way.
Hello,
If no codes are present than this would be a mechanical issue - I am assuming. I would treat each issue separately at first. If the mast won't lower, either maybe a bearing//roller could be obstructing the path. If the mast cannot tilt, maybe an oil pressure blockage. I would use the relief valve on the oil control valve to see if it lowers when you relieve pressure.
Could be an issue with oil pressure return. So inspect all return lines from the tilt cylinders and mast. If no obstructions and are allow full return, than look into actual oil control valve.
Hello.
Do you solve this? I have similar fault.