Arm moves normal in the first and last quarter and very slowly throughout the middle section of movement
Good day I suggest chek that the jacket is not swollen in the mid section, you can use large callipers. Kind regards Uffex
I’m not sure what you mean
Good day Shell The arm cylinder jacket or cylinder case if you prefer may be swollen in the mid-section, allowing fluid to by-pass. I will check if we have some illustrations for you. I assume the machine is doing this when you have the bucket in the ground and not cycling in mid air? Kind regards Uffex
The hydraulic cylinder itself could be swollen from over pressure. If you have a flexible sewing tape measure, or a smaller tape measure without the curve, wrap it around the hydraulic cylinder at the both ends and a couple places in the middle. It should be the same measurement in all places. That would be an unusual thing to happen, but I can't come up with any other explanation...
Could have more room on either side of the piston for oil to bypass seals when at mid stroke. Does the arm seem to lose power or if you lift the arm up and shut the machine off does the arm creep down? Thinking it could be an odd seal problem.
What I know about the machine when I first got the machine some functions would slow when it warmed up I changed hydraulic oil case drain filter and main filter the bad news is I cut the filters open found metal flakes in the case drain filter pulled the drain lines off the final drives one at a time ran them they were not dumping oil discovered the one drive was probably replaced with a used one I figured that’s were the metal in case drain filter came from I had dc hydraulics rebuild the hydraulic pump before i replaced the pump the main boom had the same symptoms after I replaced the pump the boom works fine now the arm is giving me trouble the left drive seems to get weak after it warms up it has been that way all long it may need to be replaced the machine has 5,200 hrs
I appreciate you guys taking time to respond
Used the machine this week to lift a set of concrete steps that weighed about 1700lbs it didn’t seem to leak down
Good day When you post that the arm slows down mid travel are you talking when digging or cycling in the air, a good test to make be sure you have full revolutions and time the arm from point of movement to full travel. Kind regards Uffex
Just moving the arm in the air no load applied it slows down but doesn’t seem to change when digging
Good day Shell What you describe can be a normal feature of some machines, to find a fault when the machine operates normally in a dig situation can be problematic. The only way to safely test the arm cylinder flow is to run a time test, most manufactures will give a standard to compare, if not we can make a calculation. Kind regards Uffex
I’m am sure that it is not a normal it also changed when I replaced the pump I was going to check the spool an port relief valve’s for debris
Good day Shell Slow hydraulics is a case of fluid flow, I would still give a check of the cylinder times. Kind regards Uffex
Good day Info that may help from Bcat. Time from movement not when you pull the lever. Kind regards Uffex
Good day A couple of docs that may help. Be aware a swollen jacket will have a faster creep speed in the center of the cylinder stroke. Kind regards Ufferx
Thanks for the info I will check that this weekend