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Dan, Technician
Category: Construction and Road Equipment
Satisfied Customers: 5124
Experience:  17+ yrs. shop and field experience with all major brands of heavy equipment and trucks - 1995 WyoTech graduate.
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Have a tachi 200 lc hydraulics very slow and not strong

Customer Question

Have a hitachi 200 lc hydraulics very slow and not strong
Submitted: 1 year ago.
Category: Construction and Road Equipment
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Dan replied 1 year ago.

Hi, its Dan.... Thanks for the request..... Check for fine metal inbthevinntank return filter indicating a pump or component failure.... Also pull the relief cartridges from the main control valve to check for debris... Damaged o rings etc causing pressure to bypass.... Let me know the results and if we need to dig deeper

Expert:  Dan replied 1 year ago.

Typing from my cell.... Sorry about the typo.... the in tank return

Filter I meant

Expert:  Dan replied 1 year ago.

If you have fine metal found in the system the failed pump or component needs to be replaced and the system properly flushed before running the new pump/ component

Customer: replied 1 year ago.
Do have a diagram of main valve body how many relief valves r there
Customer: replied 1 year ago.
I see 4 but each relief valve should control a diff component correct
Expert:  Dan replied 1 year ago.
Hi... Thanks for your response... I'm out on the road currently so I do not have access to the diagrams... What's the serial number? There should be circuit reliefs and a main relief... I would check them all and clean them.... Replace any damaged o rings. It will be a while before I get back to the shop to check for diagrams. If this is load sensing then you may only have the circuit reliefs... If so check for fine metallic glitter in the return oil/filter indicating a pump issue.... Check your pilot pressure which is pump signal pressure... Verify it is signaling the pumpump to stroke.
Customer: replied 1 year ago.
Serial is arh310306 there are 8 circuit relief valves witch I removed disassembled and cleaned all o rings looked fine nothing abnormal I removed return filter found no metal and oil looked clean but customer did just flush system and canged filter in tank what I noticed is some functions feel stronger then others the ones that seem weakest to me are tracking and boom up and down if I push boom down on ground it will barley lift machine sorry for such a long message just trying to give u as much detail as possible
Customer: replied 1 year ago.
Where 8s best place to check pilot pressure?
Expert:  Dan replied 1 year ago.

Thanks for the update. Sorry for the delay. I have been right out straight lately on the road. Is ths a dash 2 or 3 machine? 200lc-2, 200lc-3, etc

Expert:  Dan replied 1 year ago.

The functions are split between two main pumps in the one assembly. On the pumps there will be two small signal lines that signal each pump. tee in and check the signal pressure to both pump control valves. Also if you have a separate pilot pump at the end of the pumps instead of a pressure reducing valve then there should be a small pilot strainer in the pump compartment at the side of the hydraulic tank. Check it for aluminum indicating a charge pump failure.... you can check pilot pressure at the pilot manifold behind the cab or tee in to verify the pressure at each function..... Try swapping reliefs to see if the problem moves to another function. Also see if when you pull another function does the track speed up. If so one pump is likely not stroking up to full flow... Left and right travel are split between pumps along with the functions. Let me know.

Customer: replied 1 year ago.
What should charge pump be putting out
Customer: replied 1 year ago.
signals to pump
Expert:  Dan replied 1 year ago.

What is the complete model number with the dashes at the end? I will see what I can come up with for specs if I have the manuals for your model. On average, pilot pressure should be in the 550-600 PSI range. Let me know.

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