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Dan, Technician
Category: Construction and Road Equipment
Satisfied Customers: 5123
Experience:  17+ yrs. shop and field experience with all major brands of heavy equipment and trucks - 1995 WyoTech graduate.
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I have a kobelco sk135 sr it has got slow in right track

Customer Question

Hi I have a kobelco sk135 sr it has got slow in right track and I the dipper arm centre joint good pump seems good I do wonder if the pump is cranking right up computer tell me system is on
Submitted: 2 years ago.
Category: Construction and Road Equipment
Expert:  Dan replied 2 years ago.
Hi, Its Dan. I will be glad to try to help. First see if there is any metal/debris in the in tank return filter to see if there is a sign of component failure or debris and contamination still in the system from the original failure. I am assuming the system was flushed before the new pump was installed? If not there could be metal/debris in the system components and valves causing travel issues. Also the drive motors are the lowest point so if the system was not thoroughly flushed the drive motors could have taken in some metal contamination causing damage. Since this all occured after pump failure this could be the case. If with no failure the common cause is the rotary manifold seals leaking by and bypassing. Check for metal at the final drive motor ports and for excessive case drain pressure from the final drives with the track pinned at the sprocket to prevent movement and a hose run into a bucket from the drive motor case drain port with the hose capped off. Engage travel and you should only get a low volume of oil... If under high pressure that drive motor is bad and leaking excessivly internally. Let me know
Customer: replied 2 years ago.
I didn't have a pump failure it was leaking at swash plates. But system was all flushed fully drive motors have all been tested and are good. It is just slow and there seems to be air in the haydraulic oil. It works but doesn't seem to be at full hydraulic power especially on the dipper arm coming in and the computer said its all good but it's not all computers are new. So are all the filters and when changed they were clean
Expert:  Dan replied 2 years ago.
Thanks for the update. What you need to do is run through the pressures covered in the service manual and check your reliefs for damaged o rings and debris in the main control valve. Also you need to check to be sure the pumps are stroking up to full flow and adjusted properly per the service book for your serial number machine for circuit pressures and flow with a flow meter. also test pump charge Main pressure, and signal pressure ( pilot pressure )Copy and paste this link in your browser for a PDF manual available for under 10 dollars. Let me know

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