Have an issue with arm in function being slow and not having any power. Have checked pressures at pilot control valve and it's right in the acceptable range so that tells me it's either an issue in the spool or cylinder. I am planning on checking pressures at the arm cylinder. Anyone know what the pressure is suppose to be at the arm cylinder? If I take apart the spool any tips on checking out or replacing it? Thanks.
before you get too excited, reseal your arm cylinder. Its likely bypassing at the piston
it happened suddenly or gradually?
Suddenly. Worked fine one day and next morning arm was slow and weak
What about the rest of work equipment and travel
That all works fine. Just the arm in function.
Any drift in the arm? If no, check the arm spool if it moves freely
Checked the spool out. What would you call moving freely? It came out fine and when trying to depress them could maybe go a half inch. All the spools in the bank pushed down hard. It seems like a pretty heavy spring. Have the lines capped and arm hanging in the air overnight to try and see if there is drift. Left the bucket pulled up tight towards the cab over lunch and had drifted maybe 6" down. Odd thing is when the oil is cool it operates fine. It's only after several minutes of operating does it become slow and weak. Couldn't see any scoring on spool but almost impossible to see down into the hole very far to see condition of it. Thanks for the help
Your pressure at the arm cylinder will be the same as the main relief valve. You say you had the arm in toward the cab and it drifted out. If you extend the arm out will it drift toward th machine ? If it only goes one direction, it could be the circuit relief valve. thats not to say it`s not the cylinder, check the cylinder for bypass before just resealing it and still having problems.
half inch is very good. Why not checking arm in pressure when it is cold and when it is hot so you can see the difference
Check arm in pressure and arm out pressure when cold at low idle and then high idle. Repeat the process with warm oil and record findings. Before going to the expense of resealing cylinders i'd be looking to swap the arm circuit rod side overload valve with the cylinder side overload and establish if the arm in is now good and the arm out is at fault. Simple test that could save money.
Did you ever figure this out? If so what was it?
The dealer did finally figure it out. It was the arm anti drift valve I believe. It was suggested to me by another poster after I had already hauled it to dealer. Working good now. Quite the rodeo though getting it figured out