My first time on so excuse me if I make errors. Have a 1989 ls2800c 11 I have been operating for several months and has been operating perfectly. Now all of a sudden the right track runs super fast and the hydraulic system seems to be fighting itself-pulling down the motor-swiing,boom,etc.,all pull the engine down-eventually the motor gets hot from lugging. I think there might be a actuater valve or control valve open or closed or a broken wire to one of them? Also have never had any hydraulic seeps but now have several joints weeping like extreme pressure from by pass not working right or something yet the unit doesn't have much digging power. Any ideas as to where I could start checking? All filters have been changed a few hundred hours ago-oil looks great and is full. Would also love to get hold of a service manual. Thank you
I notice no one has posted to my question concerning my 2800c . What I'm wondering now is if I'm signed up to the forum properly or if this is just a question no one wants to tackle? Any answer would be appreciated. Thank you. Brian
It sounds as though one pump is stuck on full displacement, that is why the track is moving fast. Do you not have power on just one function or several? The O-rings on the reliefs may be cooked from the fluid being rammed and the pressure drop
it's a ls2800C II (series 2) not an 11
That sounds right to me, Mike, it seems like all functions are loading the machine up and there is no by pass-just drags the engine down and starts putting out the black smoke. Engine is definitely running right. I see ports in quite a few places where I can hook up a pressure guage-do you know anywhere I might start? And do you know where the by-pass valves are located on this unit? Sorry about the series #! You are correct!
Mike, I just saw where I guess I can post an answer directly to you rather than a general reply? Anyway would you read my post? Didn,t know if I needed to do this or not to let you know. Thanks
I guess also tonight when I get off work I'll go out and get on the unit and test every function and make sure I know what I'm talking about.Some could be working normally but I need to pin that down. I'll let you know. Thanks!
First thing to check is your pressure off of each pump at idle and at full throttle. Then check that the machine tracks straight at half stroke and full stroke of the pedals
OK Mike, last night I got on the machine and checked some things.The main boom and the stick cylinders by pass OK but the bucket and the right track will actually kill the engine at medium idle. I'll do as you say and check pressures. I see the test ports. One on the top and bottom. Do you know where I can get the adapter for the gauge hookup?
Im assuming this has the same style coupler as Case, John eere, and Cat. http://catalog.hydracheck.com/viewitems/diagnostic-quick-connects/pd-series-test-couplings? http://catalog.hydracheck.com/viewitems/diagnostic-quick-connects/pd-series-test-nipples? Which if so you can get at a Parker store (PD series) Eaton Aeroquip (Eaton FD) or Cat.If it does not look like this please take a picture
Couldn,t believe it but found everything here in town-will do my testing tonight. Thanks
thathilltopboy Mike, I just came in from doing some pressure testing-didn't have anyone to run the controls till today. First off I checked pump 1 and 2 with the 2 ports on the end of the pump. I got 450-500 lbs on both with no load. I took this to be the 427 figure they give for negative control signal generation? Then I started with the swing by planting the bucket in the ground to hold it. By-passing at 3400ps both ways. Next I checked arm opening and closing-By-passing at 4200 psi. Then checked boom hoisting at 4300 psi and by-passing and boom lowering at 3200 psi and by-passing. I couldn't hold the tracks from spinning because its been raining but got them up around 4000psi. As far as for the bucket, it will stop the engine running at mid range around 4200-4400 psi. Does not by-pass here closed or open! Have also experienced right track pulling engine down. I do have an owners manual and found a listing on the hydraulic pressures and all are in range except the bucket-its supposed to by-pass at 4200 psi and at about 4400 it kills the engine at half throttle without by -passing. What the right track thing is I don't know, but its going a lot faster than the left side. Checked the control cables for the steering. Full stroke either way there. Any ideas where I should go from here? Seems as if the pumps are functioning well. Other than that it seems as if it acts like a different machine. Like when you swing it while extending the arm it seems like the arm is extending faster but that pulls the engine down more than normal. Have a good day, Thanks,Brian
The 450/500 standby pressure you had, was that at idle or full throttle and what was the difference between the pressure when the engine speed was changed?
I checked it at low throttle and slightly above mid range and it didn't seem to make much difference.
What is the working pressure on the slow track and fast track when travelling
OK-I,ll have to walk along beside unit and test pump one and two pressure, right? Hope I don,t get my toes run over-HAH!