Komatsu 200lc-7 hyd issues

[chris allen]

hey guys, our excavator is starting to give fits. First off it started having turning issues while driveing. Have to really play with it to get tracks to turn machine in directions, also will notice pumps will whine loud here an there an at times the wrench icon will pop on an off an when go to the service screen it’s like there’s no cade or it’s erased. Let it set half hr an get back on it an it’ll operate without the whining but still want drive correctly At times it feels as if it has a loss of hyd power. Hadn’t hooked any gauges in yet. Need to figure out we’re an what psi we should see. Thx for help

 

[John C.]

Need serial number and amount of hours on the machine. Have you removed and looked at the suction screen inside the hydraulic tank?

 

[chris allen]

Serial is. A86420 an round 4800 hrs. We’re operating it today an it’s not whining nor has service wrench come
On. But still have to use bucket to help steer tracks around. Possibly leaking in rotation valve Not sure how to check it orher than pulling out an resealing it just to isolate that

 

[chris allen]

Also was just informed that the thumb button for auto idle don’t work anymore an have to run machine by the turn knob to idle up. Maybe the auto idle not working is not telling pumps to kick up?we just ordered new buttons for joystick

 

[chris allen]

Made a mistake bout the thumb button auto idle. I was wrong the button controlled the boost power for Lil extra help, But did get filters pulled outta tank , checked suction an replaced return filter, pulled LS an P solenoids off an took apart an cleaned small filter screens out am checked solenoids operation while off pump. Also pulled both inline filters in the big hoses in top of pumps from main valve body. Both were clean an no trash in them. Also hooked a tee in a signal pilot to the bucket dump function an read the pilot pressure of around 460 psi area. Still there’s not power Machine opperateing fast but it has no power. Push down on bucket to pick machine off ground an it want lift itself up nor load up the motor

 

[DK88]

check main reliefs, travel relief pressures.
what the ls differential pressure?
when you stall the tracks does it lug the engine down?

 

[chris allen]

Well I hooked gauges into to both pumps an was reading only round 2600 psi. Suppose to of read round 4700 area for most functions, well according to service manual when all functions are low ur supposed to adjust the relief valve in the bottom of main control valve to get the hi press up (press with boost button mashed) an then go back an adjust the low side too , an it says to do the same for the upper relief valve too that comes from rear pump, but it seems that when ever I do a function I read the same psi in both gauges that are hooked to both pumps. After I adjusted the lower relief an got press back up to 4700 area on certain functions an round 4000 on the other ones it seems to have more power now but seems Lil jerky an the machine rotates really fast now , Stalled the tracks out an think pressure was round 4000 on both sides. Think manual calls for 5600 area. Just now figured out how to get into the monitor an get electrical Codes an mechanical ones, Was looking to see how to clear them out but now sure how Not sure how old codes an if there still active. Thx for any advise an help