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Bobcat S250 Drive Noise

Coaldust

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Cargo Tanks, ULSD, RUG, Methanol, LPG
Also is it possible that the clacking I was hearing was coming from my Hydrostatic pump?
Perhaps. That just sucks, anyway you look at it. Probably didn’t have catastrophic hydraulic failure in mind, on your 2024 bingo card.
 

EZ-Man86

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Yeah wasn't really hoping to be getting this deep right now.. When I drained my hydraulic oil tank i did not notice any glitter.. After looking at it again and watching some of @howididit's vids on YouTube I am fairly certain that what I am looking at is brass from the slippers and the thrust washer.. kinda hoping against hope that my final drives might be ok, or just in need of a reseal..
 

Coaldust

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In a closed loop system like that, the drive motors will digest everything the pumps serve them. The drive motors will eventually destroy your new pump.
 

EZ-Man86

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Possible that I could just do a cleaning and resealing though?
Getting ready to go pull the engine.. Any tips?
Thanks again for all the help
EZ
 
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Of course your main filter and your fan filter will be full of gold and gray glitter. If the hydrostatic pump is the source it’s all coming apart anyway. The real test is to dead head the pump and the expectation is for the engine to stall. Yours won’t stall on the weak side. However it would suffice to say if you dump out your filters and it looks like a pan of gold start taking the engine out.
 
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Possible that I could just do a cleaning and resealing though?
Getting ready to go pull the engine.. Any tips?
Thanks again for all the help
EZ
This is not entirely accurate. Many bobcat hs pumps will case drain the debris and the filters catch most of it. As the brass breaks off the piston it falls to the bottom the hs pump and is case drained away to the cooler then then filter. A piston pump cannot “pump” if it has no brass slipper so it’s not delivering the “bulk” of the debris to the drives. It is likely his drives can survive this and NOT destroy his new pump.
 

EZ-Man86

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Main filter looks clean!
I had previously drained the hydro tank and can not see any flakes in the oil. The outlet of the case drain filter looks clean too..
 

ozarkag

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ozarks
Only if ALL debris is removed from system. Likely entails disassembling drive motors. At this point I would likely start disassembling the pumps and motors. Cleaning, repairing, rebuilding or replacingas needed.
 

EZ-Man86

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Yeah I'm going to start pulling the motor in the morning, so I can go get at the hydrostatic pump. Hoping it's just one side that failed. Then I would only have to potentially do one final drive? Definitely deeper than I wanted to get on this project but it's good opportunity to fix everything.
 
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Yeah I'm going to start pulling the motor in the morning, so I can go get at the hydrostatic pump. Hoping it's just one side that failed. Then I would only have to potentially do one final drive? Definitely deeper than I wanted to get on this project but it's good opportunity to fix everything.
Your pump didn’t likely send debris to your drive motors. That case drain you showed earlier is it shared with your hs pump case drain? I think so. What is your serial and I will get the diagram. The “case” portion of your left hand HS Pump is common with the “case” section of your right hand HS Pump. All of this goes back to the filters before it is sucked up by the charge pump, filtered again at the fan, and redelivered to the HS Pump. Now with a damaged Hs pump there is massive internal leakage. So the charge pump is now flushing the HS Pump over and over to remove debris back to the filter. Not necessarily to the drive motors.
 

EZ-Man86

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I'll get you my serial number in the morning.. 3 lines on the inlet of the case drain filter.. 2 from the final drives and I am pretty sure the other is coming from the auxiliary at the attachment point
 

EZ-Man86

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anyone able to tell me what size caps and plugs I will need for the hydraulic lines I need to disconnect in order to pull engine? Thanks in advance.
EZ
 
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Messages
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Location
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anyone able to tell me what size caps and plugs I will need for the hydraulic lines I need to disconnect in order to pull engine? Thanks in advance.
EZ
All JIC, 4,6,8,10,12, maybe 16. You will need at least 4 each of #12 and #10. The others 2 each should do. Buy a couple Amazon kits.
 

EZ-Man86

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Hey guys,
So I got the engine out and Hydrostatic pump off.. Pulled the left side apart and this is what I am seeing.. Never seen the inside of one of these, but this is not looking to me like catastrophic failure.. I was expecting the thrust washer to be gone.. There is clearly wear on the piston faces but the scratches are very sallow.. wondering if this is looking like just re sealing this and tearing in to the drive motor? Wondering if the little gold I saw was my minimal piston wear and the rest was from a final drive? Regardless I'm glad I pulled the motor based on some other discoveries..
Thanks in advance.
EZ
 

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EZ-Man86

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Here are a few shots of the trust plate on the second pump.. As well as the piston wall. There is some reflection in the pic, but the thrust plates feel smooth and only a slight "cloudy" strip around the rim.. The fit on the pistons of both pumps is tight.. No slop whatsoever.. Like I said, I am not familiar with these but nothing I am seeing is saying failure to me. Minor to moderate wear yes, but to failure.
Also whatever you call that plate in pic 4 of my last post, the one under the piston block has some very minor scratches, but no grooving. Can not even catch my nail on anything..
Going to set these aside and check my left hand drive motor.
Any help greatly appreciated.
EZ
 

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EZ-Man86

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Anyone out there? Seems like the site has been down a lot lately.. So I was surprised to find brass inside my final drive... Anyhoo this journal bearing has a pretty deep spiral groove in it.. Is this normal? It seems to be a consistent spiral which leads me to think it is intentional so that the bearing can stay lubricated?

Couple of seals throughout the drive that look worn. Nothing catastrophic.. I had oil outside of my brake section which tells me that that seal was shot.. I can see seal material inside the brake chamber.. All the brake disks look fine, no wear that I can discern.

So now I am getting confused.. Where did all the material in my case drain filter come from? All I have encountered so far appears to me, to be very normal mild wear. Hoping for some solid intel or advice before I pull my other drive.. Was having no issues with that side, but could it be that that drive dumped all the debris into my case drain filter and for some reason my left side was the only one with noticeable power loss? Grasping at straws here guys.

Any help greatly appreciated.

EZ
 

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