863g hydraulic problem

[Hotrod1830]

We spent over $500 at kc bobcat getting it diagnosed. That is where they wanted to start. I am a decent mechanic and can turn wrenches so we pulled it to save a few thousand dollars...it's more than a electrical/sensors problem b/c the steering sticks start getting stiff if we keep running it after the alarm goes off? I can put a gauge in it in the morning, but I believe this machine only has one? Tonight after watching it with the cab up and running, the right side drive motor takes about an .5" more movement at the pump while reversing than the left side but same amount of travel as the left side when going forward before movement?

What pump did you have rebuilt? The entire drive pump assembly?
Let's start from the beginning. You said your brother had it in for a two speed repair? Was it doing this same thing before, or did it start after the first repair? If it only started doing this after the repair, you may want to look into if the proper parts where installed, done correctly, or maybe debri from a failure went thru the system. Have you checked the filter?
Do the bucket controls work normally when the problem is occuring? Lift,tilt and aux?
Kinda sounds silly, but have you checked the fluid?(sorry, gotta ask) Does it look normal? Foamy?

 

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What pump did you have rebuilt? The entire drive pump assembly?
Let's start from the beginning. You said your brother had it in for a two speed repair? Was it doing this same thing before, or did it start after the first repair? If it only started doing this after the repair, you may want to look into if the proper parts where installed, done correctly, or maybe debri from a failure went thru the system. Have you checked the filter?
Do the bucket controls work normally when the problem is occuring? Lift,tilt and aux?
Kinda sounds silly, but have you checked the fluid?(sorry, gotta ask) Does it look normal? Foamy?

Yes the entire pump assembly was gone thru from gear pump to input shaft. I am not sure what the symptoms were when my brother dropped it off. I know they put a 2sp right side drive motor in it. Fresh fluid, new filter and case drain filter installed also when I r/r the assembly. Bucket controls work normal but will aid shutting the machine down if the alarm goes off and you don't stop the arms/bucket. Fluid is not foamy either. I am on this thing now as I can't afford mechanic or bobcat...do u know if this machine has just one charge pressure sensor? What r your thoughts on the extra movement needed in the pump for right side reverse? Could the motor have something wrong out of the reman facility?

 

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Yes the entire pump assembly was gone thru from gear pump to input shaft. I am not sure what the symptoms were when my brother dropped it off. I know they put a 2sp right side drive motor in it. Fresh fluid, new filter and case drain filter installed also when I r/r the assembly. Bucket controls work normal but will aid shutting the machine down if the alarm goes off and you don't stop the arms/bucket. Fluid is not foamy either. I am on this thing now as I can't afford mechanic or bobcat...do u know if this machine has just one charge pressure sensor? What r your thoughts on the extra movement needed in the pump for right side reverse? Could the motor have something wrong out of the reman facility?

Would also like to ask how one can tell of drive belt is slipping? Belt looks to be in good shape and don't see and rubber or burnt smell from a slipping belt? I

 

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Would also like to ask how one can tell of drive belt is slipping? Belt looks to be in good shape and don't see and rubber or burnt smell from a slipping belt? I

Pulled the right side drive motor that was replaced by bobcat...the hydraulic shop found a seal that separates the brake portion of the drive was shot...more than likely letting charge pressure leak by thus the low charge. Hopefully this is it and the saga is over.

 

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Pulled the right side drive motor that was replaced by bobcat...the hydraulic shop found a seal that separates the brake portion of the drive was shot...more than likely letting charge pressure leak by thus the low charge. Hopefully this is it and the saga is over.

Got the seal kit installed and drivemotors looked through. Bobcats seal kit had wrong brake piston seal in it so had to wait a few days on it. Anyways machine runs great and hydraulic r nice and quiet...but still have that darn low charge pressure light on. U guys have any suggestions on how to start troubleshooting from here? Ran it for about an hour and no issues, but didn't get at it hard either. Light kicks on at idle and goes off right off low idle.

 

[Hotrod1830]

Got the seal kit installed and drivemotors looked through. Bobcats seal kit had wrong brake piston seal in it so had to wait a few days on it. Anyways machine runs great and hydraulic r nice and quiet...but still have that darn low charge pressure light on. U guys have any suggestions on how to start troubleshooting from here? Ran it for about an hour and no issues, but didn't get at it hard either. Light kicks on at idle and goes off right off low idle.

Sorry I missed your response.
Not sure if charge pressure has been measured, but now is the time. Install a gauge, and if needed, install it Tee'ed into the gauge sender. If your light is supposed to come on at say "150 psi", and your gauge reads 145, then you have a pump problem. However, if your gauge reads 160+, then is is probably a electrical issue.
My pressure numbers are a guess, don't use those as spec's. They are for example purposes only
If in doubt, get charge pressure numbers and post the results.

 

[bode]

Sorry I missed your response.
Not sure if charge pressure has been measured, but now is the time. Install a gauge, and if needed, install it Tee'ed into the gauge sender. If your light is supposed to come on at say "150 psi", and your gauge reads 145, then you have a pump problem. However, if your gauge reads 160+, then is is probably a electrical issue.
My pressure numbers are a guess, don't use those as spec's. They are for example purposes only
If in doubt, get charge pressure numbers and post the results.

Will do. Anyone have a outlet for a good manual. All i need is the diagnostics chapter. My book doesnt give troubleshooting on anything and is a bobcat manual.

 

[Hotrod1830]

Will do. Anyone have a outlet for a good manual. All i need is the diagnostics chapter. My book doesnt give troubleshooting on anything and is a bobcat manual.

I get my manuals on ebay from foreign sellers. They are cheap, and you download them(PDF) after you pay. There is one seller from Canada, and one from Australia that I use. Can't remember the Store names though.
In my manual, the Hydrostatic system diagnostics is in the hydrostatic repair section. As for troubleshooting, All mine has is a very simple troubleshooting section at the end, nothing of any real help.
Fwiw, my 553 has a charge pressure spec of 45-65 psi. It does mention a charge pressure bypass valve. If yours has one, maybe pull it and clean it?

 

[bode]

I get my manuals on ebay from foreign sellers. They are cheap, and you download them(PDF) after you pay. There is one seller from Canada, and one from Australia that I use. Can't remember the Store names though.
In my manual, the Hydrostatic system diagnostics is in the hydrostatic repair section. As for troubleshooting, All mine has is a very simple troubleshooting section at the end, nothing of any real help.
Fwiw, my 553 has a charge pressure spec of 45-65 psi. It does mention a charge pressure bypass valve. If yours has one, maybe pull it and clean it?

Ok, pulled the sender and installed a guage t'd in. Pressures on cold start up are 300 roughly, at low idle the gauge goes down to around 250-270psi after 10-15minutes and it kicks the light on. Its a 2000psi guage so these are within 20psi probably. Left side case drain line has heat in it and right side does not while doing this test...have not hit the operation button to turn on hydraulics, just at idle. If I run it high idle it doesn't show much improvement if any on charge pressure but it will cut the light out and the alarm goes off... Could the hydraulic repair shop of missed something in the left side? Mechanic said he pumped the brakes up to 500psi and the seal held??? He thought the rest of the motor looked decent for 3000 hours and just resealed...again, after running it hard it loses charge pressure and starts applying the left side brake, in symmetry with the light/alarm and eventual shutdown. Will get on ebay tonight thanks

 

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Ok, pulled the sender and installed a guage t'd in. Pressures on cold start up are 300 roughly, at low idle the gauge goes down to around 250-270psi after 10-15minutes and it kicks the light on. Its a 2000psi guage so these are within 20psi probably. Left side case drain line has heat in it and right side does not while doing this test...have not hit the operation button to turn on hydraulics, just at idle. If I run it high idle it doesn't show much improvement if any on charge pressure but it will cut the light out and the alarm goes off... Could the hydraulic repair shop of missed something in the left side? Mechanic said he pumped the brakes up to 500psi and the seal held??? He thought the rest of the motor looked decent for 3000 hours and just resealed...again, after running it hard it loses charge pressure and starts applying the left side brake, in symmetry with the light/alarm and eventual shutdown. Will get on ebay tonight thanks

SHould of said if run hard it will shut down. From the guage it has gradual charge pressure loss at idle no use.