S595 SJC controls. Left wheels not turning

[markpps]

This unit's left wheels are not turning on their own. Right side works fine. All bucket and lift arm functions are ok. If I raise the front wheels using the bucket I can see the front wheel slightly move. The bucket functions on the left joystick work fine. Had no codes when I went to the job site to pick it up. Then while playing with it to confirm problem, when the unit is at or near idle, it beeps and show the "
HYDRAULIC CHARGE PRESSURE IN SHUTDOWN" message.has a M0514 message, and shuts down. Suspect the two issues are related.

Lastly when the unit shuts down there is a slight squeal that winds down from the engine area.

Wondering where to start. We are a landscaping company and I'm and former automotive tech by trade. Familiar with hydraulics from the Marines and the SCAG mowers we have. With decent troubleshooting skills.

 

[Phil314]

If you can start the machine and get it to run for a little bit, try this.
Since you've got the deluxe panel, start the machine and press the left arrow twice.
That should take you to a screen that will show you the charge pressure.
I think it's the middle number of the right side of the screen.
Should be somewhere between 350-390 at cold start.

The squeal could be something like a slipping drive belt, but I would think that would affect both sides.

 

[markpps]

Cold start. Ran up to 380 then settled in at 370 for awhile. after about 20 min of idling its about 290. Find it curious when I push the dead left stick forward it drops about 50psi and when I pull back it climbs about 20 psi. Its been running 30 min with no M0514. Still have the dead stick left side.

I haven't lifted the cab yet. My T770 ripped a track and I'm prepping that one for the new tracks. I need to limp-use the S595 to unload the semi when it comes and dont want it in tear down mode quite yet.

Am wondering if I have two separate issues. With the SJC I'm guessing the wheel motor is controlled by a servo. Is it possible a lever is broken or disconnected?

 

[markpps]

I just downloaded a maint manual. I'm gonna spend some time familiarizing myself with the drives and controls.

 

[Phil314]

Cold start. Ran up to 380 then settled in at 370 for awhile. after about 20 min of idling its about 290. Find it curious when I push the dead left stick forward it drops about 50psi and when I pull back it climbs about 20 psi. Its been running 30 min with no M0514. Still have the dead stick left side.

I haven't lifted the cab yet. My T770 ripped a track and I'm prepping that one for the new tracks. I need to limp-use the S595 to unload the semi when it comes and dont want it in tear down mode quite yet.

Am wondering if I have two separate issues. With the SJC I'm guessing the wheel motor is controlled by a servo. Is it possible a lever is broken or disconnected?

Startup pressure sounds good. Once warmed up, you should still see 340-350 psi. 290 is ok, but a bit low.

Dropping to 50psi is not good. I personally would not operate the machine at that point.
I think the 2 problems are related. Something broke or debris got stuck and that is causing the low charge pressure.
Next I'd probably check the hydraulic filter. I'd probably also check the motor case drain filters.
I think that machine has them, not sure where they are.

The servo controls the valve body. If the servo or valvebody had a problem, I don't think it would cause the charge pressure to drop.
It would just cause things to not work. This sounds more like a motor or tandom pump issue.

Does it also drop if you move the right joystick?

 

[brdgbldr]

Here is a link to a video on "CHARGE PRESSURE":


It gives you an idea of how to check and isolate the problem.

 

[markpps]

Startup pressure sounds good. Once warmed up, you should still see 340-350 psi. 290 is ok, but a bit low.

Dropping to 50psi is not good. I personally would not operate the machine at that point.
I think the 2 problems are related. Something broke or debris got stuck and that is causing the low charge pressure.
Next I'd probably check the hydraulic filter. I'd probably also check the motor case drain filters.
I think that machine has them, not sure where they are.

The servo controls the valve body. If the servo or valvebody had a problem, I don't think it would cause the charge pressure to drop.
It would just cause things to not work. This sounds more like a motor or tandom pump issue.

Does it also drop if you move the right joystick?

I doesn't drop TO 50psi, it drops about 50psi to around 240psi. When you pull back on the deadstick (old aircraft guy) it actually climbs about 20 psi to 310 or so. This is all at idle. With the parking brake engaged the pressure drops when you move the right stick forward and back. I don't remember how much right now but I don't think it was signifcant.

I'm going to take everything I learned from you guys and dig into it tomorrow. Ill check filters and fluids tomorrow also. My tracks for the T770 are late!

 

[markpps]

Here is a link to a video on "CHARGE PRESSURE":


It gives you an idea of how to check and isolate the problem.

Thanks for this! I had a basic understanding but the video helped flush things out.

 

[markpps]

Last fall the left drive motor was replaced under warranty after a 4 month wait for the part at 1225 hours. It was grinding. Today I removed the hydraulic filter and found chunks of rubber hose INSIDE the filter. I asked my dealer service manager and he had never seen that and also said all the lines are steel braided inside. Well my chucks are big enough to see the steel braiding on the outside of the curve so I know they are lined with rubber and probably have one deteriorating. My question would be, which return lines would be the most logical on a 3 year old machine to have internal deterioration? And where could those chunks end up that they would cause the left side not to be controlled? Once of the chunks is quite large and I w

ouldn't think it could make it past a valve body.

 

[Phil314]

Last fall the left drive motor was replaced under warranty after a 4 month wait for the part at 1225 hours. It was grinding. Today I removed the hydraulic filter and found chunks of rubber hose INSIDE the filter. I asked my dealer service manager and he had never seen that and also said all the lines are steel braided inside. Well my chucks are big enough to see the steel braiding on the outside of the curve so I know they are lined with rubber and probably have one deteriorating. My question would be, which return lines would be the most logical on a 3 year old machine to have internal deterioration? And where could those chunks end up that they would cause the left side not to be controlled? Once of the chunks is quite large and I wouldn't think it could make it past a valve body.

Were any of the hoses replace last time with the drive motor. I'm wondering if the deteriorating hose was what caused that failure too.

My guess with the size of those chunks is that it's 1 of the 2 main drive hoses. I'd pull both them off and look through them with a light or a borescope if you have one. It will be very obvious if they are coming apart inside. If they look fine, then I'd do the same with the case drain, but this is much less likely since it doesn't carry any pressure.

I'm also guessing that a chunk or 2 may be stuck in the left drive motor. Maybe the shuttle valve. You could check the return flow from the case drain hose. This would make sense since the pressure drops only when there is flow to the motor.

 

[markpps]

I pulled the left wheel motor and took apart the shuttle valve. It was clean. I couldn't turn the motor shaft by hand nor with a pipe wrench, I'm not sure if that's normal or not. Since it was so easy to get out I swapped it with the right side but forgot to check the right side motor turning resistance. The problem moved to the right side so I'm pretty certain I have a bad wheel motor.

The 3 yr warranty was up last fall and the wheel motor was replaced under warranty. I'll call my dealer tomorrow and see if they'll stand behind the part or not. Otherwise I'll be doing the teardown myself if I can find a kit for it.

Thanks everyone for your advice.

Were any of the hoses replace last time with the drive motor. I'm wondering if the deteriorating hose was what caused that failure too.

My guess with the size of those chunks is that it's 1 of the 2 main drive hoses. I'd pull both them off and look through them with a light or a borescope if you have one. It will be very obvious if they are coming apart inside. If they look fine, then I'd do the same with the case drain, but this is much less likely since it doesn't carry any pressure.

I'm also guessing that a chunk or 2 may be stuck in the left drive motor. Maybe the shuttle valve. You could check the return flow from the case drain hose. This would make sense since the pressure drops only when there is flow to the motor.

 

[haymaker]

Good luck. Please keep us informed

 

[markpps]

Stopped and spoke with the dealer. The wheel motor has a 12 mo warranty but they need to check and install. I went through my processes with them and we dropped off the machine this morning. The Bobcat has them in stock so it won't be the 4 month wait we had last fall. He said they will check pressures then replace it. Is going to inquire with tech and see if they can figure out the hose pieces issue. Going to sell this machine as soon as its repaired. We need a tracked machine. Oh.. the wheel motor has 72 hours on it....

 

[haymaker]

Thanks for the update.
Let us know what they find.
Good luck.