Forklift Hydraulic Question

[NCMau]

I have an old tractor attachment forklift that I would like to restore. Unless I am missing something, I only see one hydraulic port at the bottom of the cylinder. I suppose this is standard for this type of machinery where the return is activated by gravity. What kind of valve control can I used with this machine?

 

[boggen]

single acting cylinder = single port on the hydrualic cylinder.

just hook the one hose to one of the rear hyd ports on tractor.

be careful though. it will lift up ok, but as soon as you move the lever / valve the load could come crashing down rather quickly.

look at needle valves example.... Surplus Center

if you place a needle valve in line. between hyd cylinder and rear hyd port on tractor. you can help control how fast things move. and might help you more accurately control descent of the forks. ((much bigger of an issue once you get some weight on the forks, and forks suddenly coming down rather fast)). a needle valve that is more closed (but not completely closed) will help slow things down.

other words like the knob / lever between your legs to control speed of 3pt hitch to raise / lowers. same basic thing. just a valve for the actual hyd cylinder for the forks.

 

[Soundguy]

a forklift mass has a lot of oil to exhaust to drop... since it has to exhaust thru that hose, and thru the exhaust port on the valve.. I wouldn't expect blinding speed drops with at least some hand control on the spool valve lever.

 

[BukitCase]

While that's true, it's also true that (given a fixed diameter path) the heavier the load, the QUICKER it will drop - that's usually just the OPPOSITE of what's desirable.

Personally I would opt for one of the flow controls that gives FULL flow one direction and ADJUSTABLE flow the other. (Just be sure the FULL flow direction is UP )

The above link has BOTH types shown, in any size from 1/4" up... Steve

 

[J_J]

If you have a remote valve you can use it as a SA valve, by plugging the B work port and run the A port to the cyl.

or

Run a hose from the B work port to tank and use the A work port to control the cyl.

It will only be as fast as you move the lever.

Move a little, drop slow, Move a lot and the mast will drop faster.

I would not expect the mast to come crashing down.

A load on the forks will modify the speed also.

 

[Soundguy]

It will only be as fast as you move the lever.

Move a little, drop slow, Move a lot and the mast will drop faster.

I would not expect the mast to come crashing down.

A load on the forks will modify the speed also.

fully agree with J_J

And as he said. the spool will control the drop. want it slow? just crack the valve.. etc.

 

[NCMau]

Thanks to every for the inputs. I am going to use a flow control valve since it is already mounted on the tractor for another implement that I occasionally use. I may use a needle valve if it comes down to fast.
So, the only thing I have to do is connect one hose to the cylinder and to the flow valve power port and plug the return.
I may have an issue with the cylinder. The hose was cut and it looks like it has not been used in 100 years. The whole mast is rusty but not deep rust. I may try to apply some air to see if it moves at all. There is bleed set screw close to the top. I wonder if I should put some oil before I try the air. What do you think?

 

[Soundguy]

I'd pour some ATF into the cyl, quart if it will take it, then use air pressure to extend it out ( no load). Then take steel wool and more oil to the rod to remove any orange hays that has popped up on the chrome. Pits will eventually damage the seal, depending on amount, severity, depth, and cycles.

Gouges can be honed or filed down, brazed, and filed, sanded and polished. If pitting was in only a small band, I have seen those cleaned of rust, brazed, sanded and filed and polished smooth like glass.

Not readable over anything other than very limited geographic area

Once clean, get it retracted, exhausting old oil to bucket to see if it needs further flushing before co mingling with tractor hyds

 

[J_J]

Thanks to every for the inputs. I am going to use a flow control valve since it is already mounted on the tractor for another implement that I occasionally use. I may use a needle valve if it comes down to fast.
So, the only thing I have to do is connect one hose to the cylinder and to the flow valve power port and plug the return.
I may have an issue with the cylinder. The hose was cut and it looks like it has not been used in 100 years. The whole mast is rusty but not deep rust. I may try to apply some air to see if it moves at all. There is bleed set screw close to the top. I wonder if I should put some oil before I try the air. What do you think?

Show picture and explain about the flow valve power port and plug the return.

If you put fluid into the cyl, it has to flow out of the cyl.

 

[Soundguy]

i'm unsure what he is calling a low control valve.

I'm hoping it is just a spool he can configure as SA, or if it is da, he needs to dump the non cyl side to tank so he can exhaust the cyl and not have the other side dead headed against relief when exhausting.