The code 0521 has come up but I have no symptoms. I see were it is adjusted and have read how to do it. but i don't understand why i should do anything at this point. Please help me understand what this does and what could go wrong.
First thing you need to check is the charge pressure switch at the hydraulic filter, it would be the switch with three wires going to it. See if the switch is leaking fluid into the harness connector plug. If it is that will foul up the electrical information being sent to the main controller. If it's not leaking I'd consider replacing the switch anyway, it could be faulty. There's no way for you to test that switch as it's a Hall Effect sensor.
It would be a good idea to check the charge pressure! If the pressure indeed too high it may lead to catastrophic failure, high case drain pressure and leaking shuttle valve can cause that.
Im curious why is a pressure switch on the input of the filter? how is that related to the charge pump?
I don’t know your machine specifically but many hydrostatic pumps use different filtration options, for example Takeuchi TL130 with Sauer Danfoss Series 42 uses full external filtration option, it’s not even using built in charge pump, but share the pump with pilot circuit. I would put sensor ( if it’s possible) after charge pressure relief valve. But it might be that such a port simply unavailable, or it was most suitable location for OEM. Best thing is to know charge pressure in three locations: between pump and filter, between filter and relief valve, and after relief valve. But that’s just too much money and headache!
willy i see no oil when i pulled the 2 pin plug ... there is a single wire plug on back of filter mount too
after I start it takes a minute then it creates an error code. I will order a filter and change it next.
looking at other posts i see others have problem locating charge pressure switch. Is it possible to be one of these two sensors on the fan motor
the T300 parts manual I have shows a belt driven cooling motor .. it appears to be a hydraulic driven motor.
Ahh, you have a K series T300 with the hydraulic fan, I didn't consider that. That should be the charge pressure switch on the left side of the cartridge filter in that pic. Back at the hydraulic filter in the engine compartment is the hydraulic oil temp switch (2 wires) and the oil restriction switch (1 wire). You might want to replace that cartridge filter at the hydraulic fan. And when you pull it out drop it in a clean pan with some solvent to rinse it out and check what kind and how much debris is in that filters. See if a new filter helps with your problem. I don't have a whole lot of experience with the K series cooling system, crewchief 888 knows more about that machine than I.
a good mechanic isn't expensive hes priceless and a picture is worth a thousand words .. roger!
well its back to the T300 charge pressure issue ...first it was code 0521 (charge pressure too High)... so I changed filter, got a new pressure switch, and replaced 5 gals of oil with iso 46 (15 w?)...then I got code 0522 (charge pressure too low... I run it for 20 hours still get code 0522 ... so I am guessing iso 45 oil is too thin... I remove 2 gallons of oil and replace with iso 100 (30 w)... I work it still it trips after start up 30-60 seconds I work it, shut down and restart... still get the code sooo.... I will wait and reassess after 20 hrs ... any ideas, its no emergency as far as I can tell there are no symptoms.
I would put the gauge on that circuit just to see if you indeed having charge pressure swings, or it is electrical problems.
Ok I got 1000# gauge on order...
I have ran it with the new oil and filter and it still comes in as 522 low charge pressure so I got a gauge and the pressure at idle is 375 which is low so I am going to pull the charge pressure adjustment plug see if it needs cleaned ... try it again ... then order some shems to raise it ... does that sound right "priceless mechanics"
Is your manual says 375psi is low?
I don't have a manual for a T300 so I don't know what the charge pressure spec on one is.
375 is plenty
That’s why I asked that question! For most hydrostatic transmissions I worked with it’s plenty enough! But it’s only at idle, now need to test it under load!
manual states 410-470 is normal at high idle ... mine is 375 at low idle 390 at high idle and working the controls is goes up to 420 ... so its just a little low ... mostly with a new pressure switch I still get the code .... after I start it takes 20 seconds then the code comes in ....
so i took out the charge relief ...a spring loaded relief in an hard to get to place .... I take it out inspect it looks normal and put it back in ...in one try ... I add a shim washer to the stack to tighten up the relief ... and oh **** i can't get it in... doing the math a thin 8mm washer should raise it 30-50 # ... its very difficult to get it back in and Im working on methods.
Well! It’s counterintuitive! Your charge pressure supposed to go down when you put a load on the drive! Is your machine pilot or mechanically controlled? Specs for your charge pressure tells me that there’s something else in that circuit! Probably pilot circuit. Usually charge is 250-350, but if there’s something else upstream or parallel then OEM rase the specs on circuit pressure. What you described looks like that something else is draining your charge pressure at neutral little bit too much. My suggestion is stop with that “ snake oil shimming” thing and get to real cause of the problem!
Another thing: your original code watch charge pressure too high, now your too low but it goes up under load. I know only one component that can cause both symptoms - charge shuttle valves! Especially if you have some moisture in the hydraulic fluid and machine sat for a while!
"uncle" I give ... can't condense spring with that little sliver of extra shim ... new spring and bobbet on order
well it jumps around like the whole cab and me when i'm reading the gauge .... I rev it up is when it goes up ... the pressure jerks around , can say its a definite rise with out a redo test... so I will post this week after I get parts.
Good luck!
These might help:
its a mechanical controlled machine. Its has an error code but there are no symptoms as far as anything not working right. Code is triggered at low idle. Gauges tell me it is low according to manual. The relief parts could be worn but I can't see it, well maybe when I get the new ones I can tell. My guess is the shims are maxed out at 4 installed, making it any thicker is impossible to install, I got to have enough room to start first thread. You guys are a big help in helping me understand things. A new spring could be stiffer and that's all that is needed. we will see.
put new spring and bobbet in removed 2 slim shims to equal what I took out.... I knew I could get the same that came out back in ...I did not try more than that, that was hard enough... pressures increased slightly from 375 to 390 at low idle ... warm and under load it was 420 about the same ... I did notice i could turn with out stall ... hmmm ... I was just use to it stalling if I turned too fast ... seems much better ... still got error message of low charge pressure. Its fine for now I got dirt to move. I will leave gauge installed for a while. My test run was short... i run it a lot harder for hours. I could get more shims in to raise pressure if the engine was out. probably just ignore the code til I get more symptoms. any thoughts?
I have a 2004 bobcat t300 i just replaced my right side final drive motor now the other side is squeaky but only when the hydraulics lose power ever so often my machine will shut off and says hyd charge pressure shutdown this is my first skid steer and im pretty lost
What was the reason for replacing final drive? Was it hydraulic side problems or planetary side? Is the right side has power now. Asking because if it was hydraulic side problem, the debris from the motor damages the pump also.
We replaced the right side cause it was squeaking real bad and we looked inside and there was alot of metal shards inside it was the brakes part of it that was bad
So the loop didn’t get the metal shards? Metal shards will plug your filters very fast. They will make bypass on the return filter open up and render that filter useless. Also of your parking brake and high speed circuits powering off of the charge circuit - leak in the parking brake will drop the charge pressure.
Where would the charge circuit be at we cleaned all the filters out we was going to wait till we got the machine working right before we bought new one but we drain and replace the hydraulic oil multiple times
If you hear the squeaks - it means you’re other brake piston seal is leaking, and you burning another set of brake discs.
Yes thats what i was thinking if i get replaced do you think thats what is causing the hyd charge pressure shutdown
And you can’t clean the return filter. You can clean charge filter - but replace them after failure like this, because tiny particles are still stuck in that mesh.
Ok I appreciate it i will keep you posted and see what happens
The plugged charge filter - of course. Also leak in the brake piston. I was about to work on 300 once, but it didn’t happened, so I don’t remember where the parking brake and high speed gets powered from. But majority powers from the charge circuit, or at least from the same gear pump.