Hitachi EX330 LC-5 hydraulic problem

[JDS3673]

I own a Hitachi EX330 LC-5. The problem I am having is one track, bucket curl, and boom is slow. Very slow. I checked all of the control valves visually. All look fine. Two new pumps on the machine. Still have the same results. Anyone have any ideas on what I can check? Thanks.

 

[Bob/Ont]

I own a Hitachi EX330 LC-5. The problem I am having is one track, bucket curl, and boom is slow. Very slow. I checked all of the control valves visually. All look fine. Two new pumps on the machine. Still have the same results. Anyone have any ideas on what I can check? Thanks.

I am shooting in the dark here but I have a feeling your machine like most "modern" ones 1980 or newer have a feature that holds the pumps on low volume untill you want to use a function. I suspect that the one pump is not stroking up due to not getting a signal to do so. You really need a manual with System Operation in it to get a good understanding of how this works. I can't say more because it may confuse things. Get the right info now.
Later Bob

 

[KenAl]

This model has pump control relief valves in the valve bank. If you had a DrZX or someone who has it, you can monitor pump control pressures. Use boom up all the way and over relief. Both pump control pressures should read the same. (Boom up uses both pumps) If one is low you can have one of two problems. A stuck pump control relief valve. Right Hand side of valve bank. Let me guess its the right hand track that is slow. Or the pilot feed line going to feed the pump control relief valve at the valve bank is partially blocked due to a screen in the fitting being plugged. I have seen both problems many times.
If you don't have a way to monitor the pressures, then there is 2 pilot lines that are the stroke signals to the pump. On the hydraulic tank there are 2 lines with pressure sensors on it. Those 2 pump control signal lines are the ones that go to the pumps. You can tee gauges in it. Make sure your operator is pulling boom up ALL the way when reading the pressures. That can throw you off when they don't do it right.

 

[jackie606]

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[cutting edge]

Its got new pumps on it?

I'd say that the pump#1 regulator is set up wrong or you have a bad pump.

 

[JDS3673]

Thanks Bob/Ont. I am trying to locate a service manual for this machine. I will let you know as I progress with my diagnosis.

 

[JDS3673]

Yes. It has both new pumps installed.

 

[JDS3673]

Thank you very much for the helpful advice. This really helps. I am going to go through these one at a time until I hopefully find a solution. Problems like these are hard to diagnose. I am searching for a service manual to help me along the way also. Once again thanks. I will let you know how I fare.

 

[RaeburnRobinson]

ive been reading your post we have a 2003 hitachie that has an intermitant problem . the down presher and the bucket curl stops working . but if you go to idle and then
turn the throtl it back up it will work for a little bit then it will stop working right .all so i have read a bout this screen that may bee the problem but cant find where it is