Komatsu PC220LC-6

[josh2500]

I have a new to me Komatsu PC220LC-6 that is having some hydraulic issues. I will try to explain them the best I can. Some functions are fast and some are slow. I will try to list them below:

1. Travels forward slow, but travels fast reverse....Both are weak and wont turn
2. Swings left and right ok but still not as fast as it should
3. Bucket curls in and out ok but still not as fast as it should
4. Boom up is really slow, but if you hit travel it speeds up.....Boom up also speeds up if you hit boom out
5. Boom in is ok, but boom out is slow

I am thinking it probably needs a pump. Does anyone have any ideas or advise of where to look first given these conditions? Thanks in advance for the help.....

 

[josh2500]

Also, does anyone know of a good source to get a manual for this machine?

 

[GaryHoff]

Start with the simple checks first. Slow cycle times is likely from low pilot pressure. Check your pilot pressure, I think it should be around 550psi or so.

 

[John C.]

Much of what you describe can be more than one issue. It kind of sounds like you have compensator issues in the main valve right to start with. That is an expensive thing to fix so I would like try to find someone local with some knowledge of these machines.

Does the engine have multiple valve covers or one single one?

 

[josh2500]

It has one single valve cover on the engine. I checked the pilot pressure today and it checked out ok. Thanks

 

[John C.]

The single valve cover means it has the Komatsu built engine so you likely have a gray market machine. There will be strainer in the fuel line where it connects to the hand priming pump. It is in the hollow bolt on the suction side of the pump. When you remove it look at the end and you should see a plastic strainer that will unscrew out of the bolt. Blow it clean with air pressure and reinstall the bolt. There should be plastic or copper seals where the banjo body contact the bottom of the bolt head and the pump itself. If they are missing you can pick up standard copper seals at an auto parts store. From what you describe this isn't your problem but it is a good place to start.

 

[josh2500]

Ok. I will clean it first thing in the morning. The engine revs good and feels strong. Would this affect the hydraulics and cause problems? Is there a procedure on how to check the main pump. I don't have a manual at the moment but am working on getting one. Thanks again

 

[josh2500]

I cleaned the strainer and it is still doing the same thing. What controls the diversion of fluid between tracking and boom operation? Could this be causing the problem? The reason I ask is if you catch it just right with the travel pedals the boom will go to working correctly.

 

[John C.]

What you are describing sounds like a bad compensator valve and usually they are replaced in sets. There is one compensator valve for each function and as I recall there are at least six of them and possibly nine. The cartridges used to cost around $300 each. Replacing parts to fix this problem could be very expensive and there might be something else wrong entirely.