Komatsu Dash 5 Hydraulic Tune Up

Here is a quick video showing the fundamentals of checking and adjusting a Komatsu Dash 5 OLSS hydraulic system. Even though the machine is a PC410LC-5 excavator, the principles and nomenclature of the valves and functions are the same throughout the entire Dash 3 and Dash 5 line. I know there will be lots of questions so feel free to put them in the comments section and I'll answer them as they come up. Before adjusting the hydraulic system, you will need to make sure the engine fuel and air systems are working properly and that there are no fault codes in the electronic systems. A link to how the diagnostics for the electronics work is here:
• Komatsu Dash 5 Electro...

[@thomasmasterphiri2304]

Great job,this is a lot of useful information,keep up the good work 👍

[@repairsecrets]

Thank you for your comment. I want to do more but the virus has put a dent in my access to machines and scheduling shoots.

[@JayBirdsFab]

Great job thanks for all the help. A lot of useful information.

[@repairsecrets]

Thanks Jason!

[@excaben]

Nice job Jhon

[@repairsecrets]

Thanks Ben

[@ustarecepusta]

Thanks. Good

[@samithlakshana8801]

Good job!

[@repairsecrets]

Thank You! I appreciate the compliment.

[@abetvits94]

Gud job sir..

[@repairsecrets]

Thanks for watching the video and making the comment.

[@melvinpado9978]

Sir what is the problem causes of excavator arm in out is very slow speed...and other actuator is good...is the same unit pc120-5

[@nickolaspeacock3455]

How do you make a function that operates on the front and rear pump run on one pump only? Is that possible without going into the computer?

[@repairsecrets]

The computer only limits pump output on the Dash 5 line. To get two pump function you have to move two spools at once on these machines. You get two pump function on boom up and stick. If you want only one pump to feed on of those circuits you disconnect the pilot lines to the boom two main valve or the stick two main valve. You can then use the other to run something else.

[@rfair123]

Very informative, thanks for posting. I just bought a PC150-5 and the boom down won't lift the machine, sounds like it's going into bypass. The stick will lift the machine, everything else seems normal. I'm not sure what the machine was previously used for and am wondering if someone may have adjusted it this way or if I have a problem. Any advice?

[@repairsecrets]

In my experience when you run into a power issue like that, it's usually because the cut out function setting on the pump is a little low.

[@rfair123]

@@repairsecrets Thanks for the reply! I just received the service manual so I'm going to see if it's something I feel I can adj myself, if not I'll have the local Komatsu mobil tech come out and adjust it.

[@repairsecrets]

@@rfair123 Good Luck

[@rfair123]

@@repairsecrets Thank You

[@rfair123]

@@repairsecrets OK, finally got around to working on this machine. Some new info: Boom down and bucket in and out are slow / weak and sounds like the fluid is bypassing somewhere. If I slightly engage any other function, Stick, Swivel, tracks or aux pedal, boom down and bucket then immediately work perfectly, boom easily lifts machine and bucket in and out is fast, no bypass sound, it all just works properly. Noticed code 25 on the display for oil pressure sensor, disconnected, no change but then shows code 23. One the advice of another, we replaced the main relief valve, adjusted in and out, this made no change. Have an oil pressure switch on order but doesn't look like that controls anything that would cause this issue. Any advice?

[@lachicanonoy4642]

S done

[@repairsecrets]

Thanks for the comment.