So if anyone remembers I bought the 790e john deere in the spring. I havent used it overy to much all summer just here and there. The last time I used it the bucket was reacting really slow. I had to dig a 8 foot trench last night before it froze to hard and I basicly had no bucket control. I dug the trench without it. I does move a little faster in either direction when I dead end the stick. It aslmost feels like there is no pressure on my control stick??? Anyone have any ideas?
Sounds like the pressure switch on the bucket pilot line. Does the auto idle work on the bucket?
Im going to look pretty stupid when I say this but oh well.... Whats the auto idle for the bucket? I am still learning the ins and outs of this machine.
Well i guess i could have worded it better does the engine rev when you use any function and idle back down after you stop diging ?
Oh yes.. umm no that has never worked since I have owned the machine.
Sure it is turned on? it is the button with the crankshaft & rod pic .the same pressure switches that works the auto idle tells the pvc (computer) you have moved a lever, that was the connection i was looking at to maybe lead to the bucket problem.
It sounds to me like the bucket spool might be sticking in it's bore. Follow the hoses and lines back from the bucket cyl to the control valve. Then take a cap off the end of the spool and try to turn and slide the spool in and out a bit. If one end cap is bigger take that one off. Some valves have a spring on one end some on both. need the spring pressure off to move spool. Later Bob
Thanks for the tip bob. I will look into that. SHopguy I will try it again and see if it works just to double check it.
Yea that is a quick way to check the switches,does all the other functions work ok?
The engine speed buttons do work most times... I think there is something wrong with the servo motor that controls the throttle. SOmetimes it will surge on and off and then stop at a certain speed. right now its working.
is your machine plumbed with aux hydraulics (hammer or hoe-pak), maybe the ball valve is open?
No there are no aux hydraulics. I should note that the problem started slowly and got worse. I havent had a chance to look into it yet.. I herniated a disc in my back... but I will get into it shortly. I did have a video of it that I took and If I can get the thing to load I will put it up.
So today I had to move the hoe to a diffrent spot on the yard and now all hydraulics are slow. I went to lift the boom and it barely moved... stick to and bucket as usual. The only thing that is ok is the swing. Frustrated now. I have a video I will try to post.
http://www.youtube.com/watch?v=95SDTFMxxtY&feature=youtu.be There is the video
Has this hoe always moved this slow ? .... or did this only start to happen since it got cold (like freezing) out ?? ...... judging by your video and the snow on the ground, you might have water in the hyd system from the tank and it's frozen too ........ Just a thought
It seems from the video like something isn't stroking your pumps up to full stroke... Why it would start with only the bucket and then later affect the boom and stick is beyond me... What is the travel like? The swing is obviously normal, and your pumps have to stroke up for that to happen... I'd check at the valve blocks where the pilot lines go under/behind the cab, on a Hitachi there are a number of sensors there, I wonder if something there is haywire, perhaps a mouse ate the wires or something? That could explain why your bucket was slow first and then your boom and stick followed suit... Just a shot in the dark... Good luck!
The colder it got... the worse it got!! The bucket first though it was plus 5 today so I thought it would be better
Thanks I will look into that....... The travel is working perfect.
You can also tell by the video that the bucket will fall from the gravity as for the stick and boom now to. Would that be a pressure thing?
I'm not sure how the system works but I do believe the sensors on the pilot blocks behind the cab tell the computer if there's pilot pressure actuating one or more of the valves in the main valve bank and the system then does it's thing to stroke up the pumps according to pressure differential and a whole bunch of other parameters the system monitors. The boom and stick will fall because of gravity until they hit the ground or the straight up and down position on the stick. If you hold the control to go past here, ie. lift your tracks off the ground or move the stick past the vertical position does it slow down or keep moving? If it slows down to the creep speed in the video then there is no signal getting to either the computer or the pump solenoids. Did you say in another thread that you were in Grand Prairie or High Prairie? If you're in High Prairie, I'm just in Slave Lake for the next few weeks and could take a jaunt over and take a peek after work, it's only about an hour drive...
Yea Im in High Prairie. That would be great as I dont know to much about these things yet!
Ok I'll see if I can get Sunday afternoon off, would that work for you? I'm not all that knowledgeable either but maybe with 2 pairs of eyes we can find something... I'll let you know tomorrow if I can get part of Sunday off.
Im going to be busy Sunday so that wont be to good... but the rest of the week is fine
Ok, I'll see when I can find some time.
Well I'm under the gun to get this helicopter out the door so not sure when I can make it but I will for sure come by before heading south again. Unless you don't mind me coming by when it's dark, just not sure how much we'll be able to see then...
That be great! Well daylight is always better but if you cant its alright.. I can set up some lights.
I took a drive out there today and met Oilerman, his dog and his machine. At first the stick and bucket were very slow as previously described, yet the boom, swing and travel all worked as normal. We then swapped the pilot lines at the sensor blocks for the boom and stick and right away the stick worked normally as did the boom, just now we had JD controls... We switched it back to cat controls and the stick kept working normally. We tried a few more pilot line swaps but we just couldn't make the bucket move more than a very slow creep... While we had the pilot lines off we noticed some very fine shiny metallic particles in the oil so that has got me thinking some of it may be binding up the spools, but then why would the stick suddenly work properly by swapping the pilot lines? All the wires looked good to me and I even unplugged the high speed solenoids on the pumps to bring them up to full stroke to see if the bucket would move fast now, but it didn't... So to me it seems like the problem is in the pilot system somewhere, or some fine shavings fouling up the spools. Otherwise we're both stumped and are hoping someone knowledgeable will be able to help us out. The pilot filter will be changed asap too...
in your pump compartment ther should be a pilot filter...open up and look at what is in there...it is possaible that the slow functions are due to not enough pilot pressure being dumped off to destroke the pumps....i do believe that system is a positive charge system....i believe if you install a pressure gauge in the st port on the pilot pressure regulator valve you will see pilot pressure of 500-650 psi...it should decrease as you pull a lever thus turning on your pumps....(destroking)...if you have any debris then let me know.....together we will get it resolved..