Case skid steer - horrible groaning noise from pumps/motors

[tedf]

i get a horrible groaning noise on my 1845 (yes 1845 not the 1845C .. early production 1845) when i move control levers fwd or rev. i keep the throttle at half throttle or more, but still get this. Seems better/less noise and groaning at full throttle... or maybe the diesel engine is just drowning out the noise. The loader hyd system seem fine.... i just repacked the cylinders and bleed the lines.
i'm wondering if its air in the motors/pumps??... or i'm using the wrong hyd fluid??
i've replaced the filters (several times).. both the main hyd filter and the charge filter (under the seat).. and changed the fluid (cycled through quite a bit of fluid also from burst hoses). i bought the machine without much/any history from previous owner.
The manual states Case TCH hyd fluid... does this have something "extra" in it? i bought this expensive stuff ($30 for green 5 gal bucket at Autozone) that states "For use by: .... " and JI Case is listed. A few times i put just tractor R&O hyd oil ($15 for 5 gals "cheap" stuff) in during some of the burst hose incidents... would this cause the groaning? like TCH has anti-foaming and R&O doesn't???
the machine moves, and has power.... but i don't think it sounds right (ie not just the normal hyd pumps and motors - like my neighbor's Bobcat). This noise is deafening (i wear hearing protectors). Fluid looks normal, not burnt smelling, or milky.. hard to tell on the foam (since the tank is a real pain to fill or look in and sight glass is in poor condition).
i have the manual, and have been troubleshooting this for past few years...most of elec is gone.. so no idea on charge circuit filter warning "idiot light" - and i can't find anywhere the pressure this is suppose to be (if i inserted a pressure gauge). Machine operates fine, so must be within working limits.
Can anyone narrow down/provide insite on any of these it might be:

• One option is air leak on intake lines... i can't tell on this...how do i check?
• Improper oil ... manual states only Case TCH fluid.
• Need to drain fluid from motors and pumps and refill (contaminated??) - i only drained the tank, and not the entire system... althought burst lines sorta flushed these..
• Relief valves "cavitating" ?? i see "relief valve cartridges" in the manual, is that a filter/screen?
• Other filters/screens that restrict the flow?
• The motor case drain lines (about 3/8") are old/spongey - need replacing...but don't think that would cause this.
• other things?

i really don't want to run it if its tearing something up inside??
thnx for any help, ted
BTW: Saw the note "Bleeding of hydraulic/hydrostatic system"...
my manual describes draining and refilling.. no mention of expert service personnel having to perform this... although manual was written in 1976

 

[Tazza]

Well, i don't know much about these machines....
How easy is it for you to access the hydro pumps? as i would like you to do a quick test. If its easily accessable run the machine and move it around a bit then turn it off, feel how hot the hydrostatic pump is. If it is hot you have cavetation, this could be from a blocked suction filter or air in the system. I was told that you have to get a *professional* to bleed the system. Bobcats you just run them, they will auto-bleed.
I believe the case service ppl are useless from what i was told, they will not tell you ANYTHING but they are happy to fix it if you pay. You can try asking if there is a suction line filter.
Good luck, see how you go.

 

[tedf]

Well, i don't know much about these machines....
How easy is it for you to access the hydro pumps? as i would like you to do a quick test. If its easily accessable run the machine and move it around a bit then turn it off, feel how hot the hydrostatic pump is. If it is hot you have cavetation, this could be from a blocked suction filter or air in the system. I was told that you have to get a *professional* to bleed the system. Bobcats you just run them, they will auto-bleed.
I believe the case service ppl are useless from what i was told, they will not tell you ANYTHING but they are happy to fix it if you pay. You can try asking if there is a suction line filter.
Good luck, see how you go.

>> How easy is it for you to access the hydro pumps? as i would like you to do a quick test. If its easily accessable run the machine and move it around a bit then turn it off, feel how hot the hydrostatic pump is. If it is hot you have cavetation, this could be from a blocked suction filter or air in the system.
The pumps are fairly easy to get to, under the seat. i will check how hot the pumps & motors get. The loader/bucket works fine (they get jerky when the fluid gets low) and drive motors actually has power... its just very noisey. it has quite a bit of oil in belly pan from old leaks.. so its hard to tell if suction line has small leak when sitting. i need to clean the belly pan and then see whats leaking now.
>> I believe the case service ppl are useless from what i was told, they will not tell you ANYTHING but they are happy to fix it if you pay. You can try asking if there is a suction line filter.
The local shop is very small tractor supply and i can order Case parts (so not much knowledge in this area)... and when you call the big Case shop that may know something.. "bring it in and we will check it"..and they are use to working on $50k and $100k machines, so a $2000 repair is normal.... i may try calling them again, and see if i can get something out of them... at least if there is suction filter somewhere that i am missing.
do the Bobcats have the "case drain line"? Appears to be smaller line from the drive motors to a manifold returning to the resevoir. seems to be for excess oil to bleed from motors back to resevoir.

 

[Tazza]

>> How easy is it for you to access the hydro pumps? as i would like you to do a quick test. If its easily accessable run the machine and move it around a bit then turn it off, feel how hot the hydrostatic pump is. If it is hot you have cavetation, this could be from a blocked suction filter or air in the system.
The pumps are fairly easy to get to, under the seat. i will check how hot the pumps & motors get. The loader/bucket works fine (they get jerky when the fluid gets low) and drive motors actually has power... its just very noisey. it has quite a bit of oil in belly pan from old leaks.. so its hard to tell if suction line has small leak when sitting. i need to clean the belly pan and then see whats leaking now.
>> I believe the case service ppl are useless from what i was told, they will not tell you ANYTHING but they are happy to fix it if you pay. You can try asking if there is a suction line filter.
The local shop is very small tractor supply and i can order Case parts (so not much knowledge in this area)... and when you call the big Case shop that may know something.. "bring it in and we will check it"..and they are use to working on $50k and $100k machines, so a $2000 repair is normal.... i may try calling them again, and see if i can get something out of them... at least if there is suction filter somewhere that i am missing.
do the Bobcats have the "case drain line"? Appears to be smaller line from the drive motors to a manifold returning to the resevoir. seems to be for excess oil to bleed from motors back to resevoir.

Yeah, bobcats have case drain lines, this is for the internal leakage of the motors. These line have alomst no pressure running through them.

 

[tedf]

Yeah, bobcats have case drain lines, this is for the internal leakage of the motors. These line have alomst no pressure running through them.

Would these get blocked and cause pressure build up in motors/groaning, etc..?... i'm grasping at straws with this one...

 

[Tazza]

Would these get blocked and cause pressure build up in motors/groaning, etc..?... i'm grasping at straws with this one...

well, i guess its possible.... It all depends if it does indeed have case drain filters.
Its worth a look.
I really don't know if the motors actually make any noise accept a high pitched noise, i think its mostly pump noise.

 

[M700man]

well, i guess its possible.... It all depends if it does indeed have case drain filters.
Its worth a look.
I really don't know if the motors actually make any noise accept a high pitched noise, i think its mostly pump noise.

Wonder if he found the problem ?