Need a Shop Mechanic / Technican (EXCAVATOR)

[exkx61]

I have a Kx61-2 excavator with thumb. I've been told that the thumb (Service port) should be set at a lower pressure than the digging bucket, in other words the bucket should over power the thumb. The pressure must be set close to equal now because the main bucket pin is taking the excess load when grasping a heavy item and is getting bent. I did replace the pin last winter and its now slightly bent.

My WSM does not say anything about a pressure relief valve for the "service port" . I know most of talk here is about tractors but this is a Kubota and someone with experience may have run across this with a backhoe or excavator. How do I set the pressure relief on the service port? Any help would be great. Thanks.

FYI: The bucket pins should be easy to remove when switching out digging buckets...when slightly bent they come out hard and yes they are made of proper pin steel.

 

[375Matt]

I'm picking up my KX71 tonight but when I asked the dealership about spare parts I may need they mentioned I may want to get some extra pins. I'm wondering if it is a common problem?

 

[Stumpy]

Sorry, know just enough to get myself in trouble with hydraulics and less about thumbs.

I believe what you're looking for can be found on the spool operating the thumb. If it's got a pressure relief there should be something you can adjust it with on the valve. That's a wild a$$ guess though.

 

[firejunkie]

There is a relief valve setting on the valve block, but to set it, you need to know your pressures, using gauges and in some case need to set multiple pressures to work in conjunction with the one you are trying to "fix". This is an old school way of not overpowering the thumb and bending the cylinder.Basically it is for operators that don't know how to operate the machine. bent pins and cylinders are operator errors, very very very rarely is it a design flaw, or bad pin. When you curl the bucket into the thumb (empty) ,the thumb cylinder should move in slightly 1/4"-3/8" that is all after that your exceeding the relief and will bend or break something.

 

[exkx61]

There is a relief valve setting on the valve block, but to set it, you need to know your pressures, using gauges and in some case need to set multiple pressures to work in conjunction with the one you are trying to "fix". This is an old school way of not overpowering the thumb and bending the cylinder.Basically it is for operators that don't know how to operate the machine. bent pins and cylinders are operator errors, very very very rarely is it a design flaw, or bad pin. When you curl the bucket into the thumb (empty) ,the thumb cylinder should move in slightly 1/4"-3/8" that is all after that your exceeding the relief and will bend or break something.

I do understand what you are saying, but there are times when you can not see the thumb or cylinder flex such as when picking up a load of brush,limbs etc. Did talk to local dealer and they said the thumb should be set 200-300 lbs less than bucket pressure that would allow the bucket to over power the thumb. Thanks for your reply.