help zx160lc when i boom down boom goes up

[Btad]

help i was using it to day and all of a sudden the boom started only going up
when i boom down is goes up slow when i boom up it goes up normal
this is a 2006 Hitachi zx160lc no dash
S/N FF01F1Q006474
any idea where to start
i have a drzx and a presser test set
thanks in advances

 

[Vetech63]

Does the boom stay still with the joystick centered?

 

[Btad]

it does bleed off real slow it has done that for a long time

 

[Btad]

Does the boom stay still with the joystick centered?

it does bleed off real slow it has done that for a long time

 

[Vetech63]

Check for a stuck plunger on the joystick first. After that I would check the pilot pressure at the main valve spool ends for the boom. If that pressure is comparable per side, it will be time to approach an issue with the main valve centering or a sticking valve spool.

 

[Btad]

Check for a stuck plunger on the joystick first. After that I would check the pilot pressure at the main valve spool ends for the boom. If that pressure is comparable per side, it will be time to approach an issue with the main valve centering or a sticking valve spool.

Just started checking some more information it does not mater what Joy stick I move or which way I more them the boom goes up. The "boom up pilot" reads MPA ~75
when raising boom, and when I move any other direction with the joy sticks it reads about MPA ~30 for a split second. Boom angel reads .25 volts no matter the angel.

 

[Vetech63]

This is sounding like your main control spool has an issue.

 

[Btad]

This is sounding like your main control spool has an issue.

I think you are right with the pilot boom up disconnected it still went up
Any way to test the main spool?
And where is it located
And thank you thank you for all the help

 

[Vetech63]

You can follow the boom cylinder hoses to the main control valve. Then follow the pilot lines to where they go to on the main control valve. Make sure all your moving functions are rested on the ground before you disconnect anything. I would remove the spool caps on each side first and see if one of the centering springs is broken and wedged inside the cap. Once the caps are off you should be able to freely move the spool back and forth..........if not something is in the spool bare and is preventing it from proper movement.
Since you stated that the boom had been previously drifting, I'm thinking there is part of a cylinder packing wedged in there somewhere.

I am not extremely familiar with your particular machine hydraulics, so I don't have a schematic to guide you with. What info I'm giving you is "general rule of thumb". Taking pics of the main valve may help. I believe the pic you took is of the pilot manifold.

 

[Vetech63]

You can follow the boom cylinder hoses to the main control valve. Then follow the boom pilot lines to where they go to on the main control valve. Make sure all your moving functions are rested on the ground before you disconnect anything. I would remove the boom spool caps on each side first and see if one of the centering springs is broken and wedged inside the cap. Once the caps are off you should be able to freely move the spool back and forth..........if not something is in the spool bore and is preventing it from proper movement.
Since you stated that the boom had been previously drifting, I'm thinking there is part of a cylinder packing wedged in there somewhere.

I am not extremely familiar with your particular machine hydraulics, so I don't have a schematic to guide you with. What info I'm giving you is "general rule of thumb". Taking pics of the main valve may help. I believe the pic you took is of the pilot manifold.

 

[Vetech63]

Site was lagging bad.............sorry for 2 responses saying the same dam thing.

 

[Btad]

Site was lagging bad.............sorry for 2 responses saying the same dam thing.

No problem on the double post I had the same problem yesterday
I do have the tickets Manu
I was not sure if you were talking about the boom spool or something else
Now I under stand
And yes I did my pilot test at the manifold
And I can't thank you a nuf
For pointing me in the right direction
Do you know if the spool can be rebuilt or just replace
Thanks again

 

[Vetech63]

There really isn’t anything to rebuild. Once the spool is removed you can used compressed air and clean the bore. Use some fine Emory cloth and clean up any scratches on the spool, then lube it with clean oil and stick it back in the bore. If it slides back and forth easily with your fingers then you are done. If it still sticks there is a possibility the spool may be bent. That’s a bit trickier but possible.

 

[Btad]

Thanks

There really isn’t anything to rebuild. Once the spool is removed you can used compressed air and clean the bore. Use some fine Emory cloth and clean up any scratches on the spool, then lube it with clean oil and stick it back in the bore. If it slides back and forth easily with your fingers then you are done. If it still sticks there is a possibility the spool may be bent. That’s a bit trickier but possible.

Will let you know what happens

 

[uffex]

Good day
May not be the case however if the piston has sufficient leakage (bypass) the cylinder's will always extend to displace the fluid puping in.
Kind regards
Uffex

 

[uffex]

Good day
Similar situation, the piston head had become divorced from the piston rod. If you can by using the shock valve lower the bucket to the ground when you raise the boom, you will hear a clonk from the boom cylinders.
Kind regards
Uffex

 

[Btad]

There really isn’t anything to rebuild. Once the spool is removed you can used compressed air and clean the bore. Use some fine Emory cloth and clean up any scratches on the spool, then lube it with clean oil and stick it back in the bore. If it slides back and forth easily with your fingers then you are done. If it still sticks there is a possibility the spool may be bent. That’s a bit trickier but possible.

Well went to work on it today I got 1 side opened up the swing spool is real tight there are no burbs I cleaned it with 800 grit papper and then cleaned it it did not chang it at all so I took a difrent spool to test the boor and it was OK so I think I have a bent spool with that said I have no problem with the swing
And then the snow hit so I had to cover it up and leave I will check to see if the spool is bent
is it OK as long as I don't have any problems with the swing
Thanks

 

[Vetech63]

I’m not understanding why your messing with the swing spool. It didn’t have an issue did it? Don’t use different spools in different bores……they are machine fitted.

 

[Btad]

I’m not understanding why your messing with the swing spool. It didn’t have an issue did it? Don’t use different spools in different bores……they are machine fitted.

Sorry I was moving them all to check for free movement I take it that was a mistake
And correct swing is working
Don't you just love working with amateurs I hop I did not mes up to bad

 

[Vetech63]

Have you tried the boom spool yet. Concentrate on that one