Komatsu PC50 MR Question

rstone

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Mar 8, 2008
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I am a newbie to the mini excavator. The PC 50 that I bought seems to be weak in the cab rotation when the bucket is extended and has maybe clamped onto some loose brush.
I am not sure how strong it should be when at this point. if i pull the bucket closer to the cab and still have the loose brush clamped, it moves better. Should this be happening or is something wrong?
 

gtbensley

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Mar 17, 2016
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Kubota B7500, Case CX36B
Sounds normal to me. Thats a lot of leverage with the boom extended and thus takes a lot more force to push things. Swing motors are not supposed to be strong enough to push a whole lot. Is it weak or does not not want to work at all?
 
  
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rstone

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When it is retracted, it will move good. It also moves ok when extended when not loaded . When loaded it doesn’t want to move Or moves slow
 

pjbci

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JD 4840, Deere 5075e, 450j, Cat D4k2, Kobelco 160, Volvo EC140el, deere 310, komatsu D31px22, IH 1486, MF 135, MHF TO35
2x on the thats normal. Gtbensely summed it up. I own two larger machines and run em almost everyday. Too much swing torque would bend the boom/stick so they (swing motors) are sized correctly as to not damge itself. Dont try to knock stuff down swinging. If it cannot move sideways, do not swing faster to ram it.
 
  
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rstone

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Thanks Guys for the info. That helps to understand the why behind everything
 
  
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rstone

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One other question. If the turning is weak, can the motors be rebuilt?
 

gtbensley

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Mar 17, 2016
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Kubota B7500, Case CX36B
Yes, you should be able to have the swing motor rebuilt if thats the issue. It may have a seal that is leaking internally and lowering pressures.

Is it hindering use normally or just when you try and swing with the boom extended and a pile of brush in tow or knocking a pile over? My CX36b can drag a tree top around extended with not a lot of issue. But if it gets stuck in other brush it does not want to move it.
 

Seven Gables

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Jan 30, 2019
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jd 5115m , Ford 545D, Kubota M8540, NH t4.105 , Ford 5030, Ford 4830, NH TN 95FA, Volvo EC60E
Another test you could try for your swing power , put the machine on a decent incline and with a full bucket see how well it swings it uphill. See if there's a point in the arm extension that it can't move it. Will it rotate it uphill at full arm extension ? Also do you hear the swing motor relief valve opening when the swing motor runs out of power?
 
 
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