# Kuhn 600GMD bar only raises halfway!



## i9markos (Oct 17, 2014)

I have a 1995 model Kuhn 600GMD disc mower. I have it attached to my tractor but the bar on the mower will only raise up halfway. I checked that I connected everything correctly and my tractor is a 2007 Kubota M6040DT, which should be plenty of tractor to handle this task. Does anyone know what I can do to fix this? Bought this mower used recently and this is first time I was able to hook it up and try it out. Any help will be appreciated.


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## slowzuki (Mar 8, 2011)

On my mower the vent on the unused end of the hydraulic cylinder was plugged and the seals on the cylinder leaked enough oil that it filled that end half full and stopped it from lifting.

Solution was to drill the bronze sintered vent carefully with a rag around the bit as it was under pressure even lowered. A burst of air and oil came out, then next raise of the bar oil shot out all over the cab. Just dribbles a bit each use now, been meaning to repack cylinder soon.


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## i9markos (Oct 17, 2014)

slowzuki said:


> On my mower the vent on the unused end of the hydraulic cylinder was plugged and the seals on the cylinder leaked enough oil that it filled that end half full and stopped it from lifting.
> 
> Solution was to drill the bronze sintered vent carefully with a rag around the bit as it was under pressure even lowered. A burst of air and oil came out, then next raise of the bar oil shot out all over the cab. Just dribbles a bit each use now, been meaning to repack cylinder soon.


Thanks for the reply. My cylinder is not leaking at all however. I will check tonight to see the vent hole is plugged. Thanks


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## slowzuki (Mar 8, 2011)

It had no external leakage, not a drop at all as the plugged vent kept all the oil inside. The sintered plug looked clean but the dealer told me they had fixed a lots of them all with the same problem so I trusted them and drilled the hole that fixed it.



i9markos said:


> Thanks for the reply. My cylinder is not leaking at all however. I will check tonight to see the vent hole is plugged. Thanks


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## krone.1 (Jul 28, 2013)

Are you sure it is hydraulic and not something mechanical? (i.e. transport lockout not releasing). Do you have your hose in the raise port? (Back to raise, forward to lower). If you have your hose connected to the lower port, then when you push the remote lever forward to raise, sometimes you can go partially into float and not get full pressure/flow to the cylinder.


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## Tx Jim (Jun 30, 2014)

Similar disc cutter NH 617 & JD 275 have a safety lock that limits the height that cutterbar will raise until the safety lock is moved out of the way to raise cutterbar 90 degrees for transport. I wonder if Kuhn has the same safety lock?


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## i9markos (Oct 17, 2014)

slowzuki said:


> It had no external leakage, not a drop at all as the plugged vent kept all the oil inside. The sintered plug looked clean but the dealer told me they had fixed a lots of them all with the same problem so I trusted them and drilled the hole that fixed it.


I checked the vent hole and it was clear. I put some degreaser on it and cleaned it a little anyways. It ended up being that my mechanical latch was sticking. I fixed that and it finally raised the whole way. Thanks everyone. Now on to my original chore, replacing rounded out fill and drain plugs.


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## slowzuki (Mar 8, 2011)

Nice and easy fix! On the drain plugs, I had to weld a hex nut in the recessed allen head plug so I could get a socket on it.


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