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Datson/Nissan fork lift

James H Clark

Stainless
Joined
May 11, 2011
Location
southern in.
Got a small 3000 lb. fork lift that has began to stop about a foot off the floor when letting the forks down. Can't get it to go lower, but by setting for a few days, forks will slowly go down by themselves. It sounds like a hydraulic problem, but not sure where to look. Has anyone run into this before?

JH
 
There is usually a restriction somewhere in the circuit so the load can not be lowered to rapidly, but allows full flow when lifting. I would look for dirt or other blockage in this restictor. Cant help with the location, sorry.
 
I just redid the cyl seals on my datsun 5000lb. It has a center freelift cyl and two tall cylinders on either side to lift high (3 stage mast). The two tall cylinders are connected together and one of them has a flow restrictor at the bottom. You need the forks raised up to get to it, or even see it.
If you remove it be sure to block up the mast so it can not come down.;)
 
It will also have hose bust protection.....required by law now,I think.......hose bust valving is usually in a block welded to the cylinder,or even in the solid base of the cylinder......now,Im not sayin you should remove it,but that is likely where your problem is ......and you are lowering too fast ,and the valve is moved by the pressure differential.
 
I appreciate every ones input. I should have stated that this is a 1973 model. Would it be likely to have the hose bust protection on it? I haven't delved into the manuals very much, but have never noticed anything like that. Will have to look closely now.

On edit: I also should have said that it only stops when it is about a foot or so above the floor. Above that it works good.

JH
 
It will be a internal mechanism to stop the cylinder banging down......try lowering a lot more slowly at the bottom ,see if it still happens.........many hydraulic machines have a coil spring and plate to restrict flow as the piston nears end of stroke..........it will be inside the cylinder,so not easily removed or repaired.
 








 
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