No charge pressure on 2007 450ct

I have owned this machine for 50 operating hours. H-pattern pilot controls. I am looking for some advise as to what to do next. I lost hydraulic pressure on a slightly uphill slope. got a charge pressure warning illumination. I had tilted the bucket down to unearth a small tree, and was creeping forward to curl the dirt and pull the tree loose. I had not checked the fluid that da,, but had noticed the day before that the fluid level was good, and the fluid was a little darker than usual (only ran it for about 2 hours the day before). When I lost power, I checked, and level was fine, but fluid was dark. Drained the tank thinking that either clogged up a hydraulic filter ( since it was the only one I had not changed) or that the sensor for the charge pressure was bad. When I drained the fluid, it had some metallic/shiny to it. The only way to describe is it was similar to clutch/gear material that you would see when emptying a differential in a car though not as many parts per million of metal if you will. I now believe there is some trash in the hydraulic tank as well since the machine sat for 3 years prior to me owning it. Learning expensive lessons on how important some things are on these. I only got about 6 gallons of oil out of the reservoir even though the oil was in the middle of the sight glass... When filling, it took 8.5 gallons to get back to middle of the sight glass. Fired it up and nothing. Thought that the slope had something to do with priming/ gravity feeding to the hydraulic pump, so added another 1.5 gallons to get to 10 total. Still nothing. So I put in a new charge sensor on the filter manifold. Nothing. Cracked the hydraulic filter and started. no oil came flooding out. Next cracked the high side hose from the hydraulic pump to distribution block??? mounted on the passenger side and started the engine. Nothing. Took the hose clamp loose on the feed line to the hydraulic pump. There was oil present/ running out with the clamp just loosened. So I know there is at least oil in the pump and hose.

Long story to get to where should I go next? I have the repair manuals, and have a basic understanding of hydraulics, but dont want to throw parts. I plan on pulling the hydraulic pump tomorrow, and looking at the gears/shaft tomorrow (could be the reason for the fine metal in the oil). Is there anything else that I should look for? I cannot test the hydrostat without hydraulic power can I? Is there an assumption that the hydrostat will be bad if the hydraulic pump shelled? Is it possible that there is something broken in the hydrostat that would cause the pump to not turn? What should I be looking for?

I had initially planned on just starting this up with the new oil, and letting it circulate for half an hour then draining and refilling and changing the filter again to try and flush the system, but reading more, I dont know if that is a great idea. Its what I would do with a transmission or motor that was rebuilt. Now planning on changing the tank suction filter as well.

Any advise would be of help.

Thanks,
Cfry

After you pull the hydraulic pump crank the engine and see if the drive for the pump is turning.

Kith,

Thanks,

That was actually my plan, and was out in a field doing it while you responded. Turns out the gear pump is good. Has suction when turning by hand. I was a little worried about if it was safe to crank the motor, but had looked at the assembly drawing last night, and looked to be a direct drive through coupler sleeves on the "main" shafts. Cranked it anyway after getting frustrated.

The hydrostat is not turning at the pump. At this point, I think the only thing to do is pull the drive, and see what is wrong, though in reality I have no idea if I want to try and rebuild (or where to even get parts) or just purchase a new one. Not scared of the mechanical side of this, as I have rebuilt my share of transmissions, but you dont know what you dont know. So now it will be pull and inspect. Probably cheaper to just order one.


Anyone have a suggestion on vendor? Loader Parts Source has one for 2600. Any that I should stay away from?

Thanks again.

If the loader hydraulics were still working when you had no drive - the pumps are turning.
Unfortunately, the metal fleck in the oil is always a bad sign.
Did the drive show any signs of weakness before it actually stopped working?

I can't suggest a supplier, but hydrostatics are expensive to repair.
If there is any sign of wear in the main pump rotating groups - the same wear will be present in the drive motors - you shouldn't fit a new pump to worn motors.
It's a complete waste of money, as the worn motors will contaminate the new pumps & you will be back at square #1 in just a few machine hours.

alrman said:

If the loader hydraulics were still working when you had no drive - the pumps are turning.
Unfortunately, the metal fleck in the oil is always a bad sign.
Did the drive show any signs of weakness before it actually stopped working?

I can't suggest a supplier, but hydrostatics are expensive to repair.
If there is any sign of wear in the main pump rotating groups - the same wear will be present in the drive motors - you shouldn't fit a new pump to worn motors.
It's a complete waste of money, as the worn motors will contaminate the new pumps & you will be back at square #1 in just a few machine hours.

Click to expand...

Alrman,

Just to make sure i understand. You are referencing the final drives when you say drive motor? If so, the logic makes sense. My only question is could i put the hydrostat pump on, then move it onto a trailer, get it to the shop, then swap drives and reflush the system again? No desire nor in a good spot to be pulling tracks off in the woods if i can help it.

Yes, when I say drive motors - I mean the hydraulic motors that power the final drives.
Personally, I wouldn't fit new pumps to it, without seeing what damage has occurred to the old ones.
Certainly, wouldn't fit new pumps to run worn motors with that unknown factor.

If you wanted to tow it - remove the covers from the final drives & take out the sun gears on both sides - that will allow it to move freely & get to somewhere be loaded up & taken to a workshop.
Just make sure it is sake to do so if it is on a slope......

Thank for the advise on how to tow it. I have access to another piece of machinery that I could drag it with pretty safely. The drive motor makes sense to me. Now that I think about it, I had rebuilt the tensioners about 10 hours ago, as the rods were pitted and wouldnt adjust. This allowed me to put proper tension on the tracks. I now think that this is what did the hydrostat in. I had noticed a slow loss of power in the drive, but attributed it to being in very soft dirt where I was sinking a few inches. This machine never did like to turn in place. I am now thinking that the slack in the tracks was a cushion for the failing drive motor(s). The fluid discoloration started after the day I put proper tension on the tracks. Will now look at removing those as well and having them rebuilt.

While painful to hear, I cannot complain. Bought the machine for $7500, and the motor runs strong. Always a chance that these things go wrong. Even footing 10K for the drives and pumps is less than I could have bought a used machine. So there is a sunny side. Just hoped to get a little further down the road from the purchase before I shelled it all out....

Again, thank you for the info and making me see the big picture.

You are going to have to pull the hydrostatic pumps to fix the drive or to have pumps repaired. As previously mentioned if your pumps are bad do the drive motors to. It is a closed loop system on the drive.

Alrman,

In pulling the sun gear, do you have any suggestions? I released track tension, but I cannot manage to remove them. Am i pulling the entire cluster, or just the sun gear? Would pulling the planetaries first be appropriate? Seems bound still. Cannot seem to find any info on the best way to go about this. Should the track be off the ground?