I have pc200-7 sn c50743 arm digging function weak.no codes. about 2000 psi. touch the right pedal a little and it adds power to the weak arm. checking things out I find the arm in compensator valve has a smaller spring in it than the one in the arm out compensator valve. is this correct? thanks
If it is like the Dash 6 machines touching the travel pedal puts the pump in power max. The relief valve pressure is raised along with the pump output. Does the arm drift down when held in the air?
No it doesn't John. I have been unable to get it into power max mode and it also is not load sensing.You have to use a light touch on the controls to keep it from bogging.Relief pressures seem to be ok on everything except arm digging. Control circuit oil pressure (page 20-120) tested low @300psi. is that adjustable with screw on self pressure reduction valve? Gonna work my way thru it a piece at a time.. thanks
You apparently have a problem in the pumps or control circuits then. Pilot pressures were always around 300 PSI. It actually only takes a couple of hundred PSI to make the system work. Does the arm drift down and if so how fast.
No the arm doesn't drift down much at all.
If you use a watch and a tape measure how much does the bucket settle in a minute when being held in the air and extended half way out?
I'll check it and get back I just got the merge divide valve back on and I need to add some oil. Pretty much covered up with chores today! Thanks
ok I checked the drift today. At full reach it dropped 3/4 of an inch. At halfway 1/16 of an inch. I r+r'd the merge divide and self pressure reducing valve and found nothing remarkable. Replace arm compensator seals with some crappy Chinese seals. All of a sudden arm digging pressure went up to 5000psi. Then I started digging up a stump and the arm pressure became erratic. Pull the arm in sometimes you get 5k sometimes you get 2k. Then finally it returned to the way it was only 2k . Has to be something in the merge divide or self pressure reducing valve, or the poor fitting Chinese seals in the arm comp valves. I'm leery of those Chinese seals.
If changing the compensator seals made the problem change then why would you consider doing anything with the merge divide or the pressure reducing valve? Put new factory seals in the compensator and move on.
I did those first while waiting on the seals so don't know for sure which fix made the difference but it seems we might also have a ppc problem. If you let the stick get into swing/arm dig not even enough to make it move then the arm dig pressure is 2k. Slide it over toward the middle and it loads her up but also sometimes it doesn't load up. Will be adjusting swing ppc and checking ppc pressure.
Now your explanation seems to indicate a problem in the joy stick control. If the PPC pressure were bad all the functions would be off. You are explaining that only the stick is bad? Tee a gauge into the pilot hose going to one of the arm functions and watch it when it gives you problems.
Yeah I tried to.do that today but I didn't have the right fitting. I did swap ppc oil pressure switches between arm dig and arm dump but no difference. When u pull arm in and pressure is low then you push right travel pedal some you hear /feel some kind of transition and pressure pops on up.(m divide valve?) Maybe check r travel comp valve? I'll be hunting that fitting. Thanks
does the auto idle work?? reving up and down on each function ? should have like 425-450 psi control pressure hows the comp valve look? did it mark up the bore in the valve? ive seen comp valves with no seals and they still work ok, not great but ok. does the machine track straight?
Auto idle does work. Pretty sure on each function. Only 300psi control pressure. Comp valves not marked up. Machine does track straight. Where would control pressure likely be leaking off? Does the adjustment screw on the self pressure reducing valve do anything. When it stops flooding here in TX I'm gonna continue testing. Thanks
double check the auto idle.. that can effect merge divide logic. repair joystick free play as required ive never had to adjust one. pull it apart and see if the screens plugged causing a pressure drop. pull the whole 2" x2" block off 3 8mm hex bolts and a line. there are dime screens in there that could be plugged as well.
Will check the auto idle in all functions. Joystick has been adjusted. Have removed merge divide and self pressure valves. Both were clean and looked good including screens.
what the unload presure? any metal or brass in suction strainer?
Around 530psi and 550psi don't remember if front or rear was higher. Nothing in the tank filter.
Ok auto idle worked on every function but the arm in function was as usual sporadic. it would load up to about 2k and you would have to fiddle with the stick toward left or right swing to get full pressure. after some of that action it finally just quit getting to full pressure and auto idle would even idle it down while u had the stick pulled all the way back. So I did some more checking and found that when u hold the left stick back(arm in) you got 2k psi but if use any function with it, it will add pressure and when that pressure reaches 3100-3500psi the arm in function will take control and u get full pressure. But it wont work with right travel pedal. You assist it with right travel pressure and it goes right back down when u release the pedal.