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257B3 lift arms floating

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Plumberboy76

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Joined
Mar 14, 2013
Messages
22
Location
Maryland
My 257 B3 has play in the lift arm hydraulics. It doesn't drift down with a full bucket but when back dragging or cutting grade the rams will move an inch in either direction. This makes it extremely hard to cut grade or back drag. It's like float mode but not as much play. Also when traveling with an empty bucket and I hit a decent bump the arms will do the same play and jerk around, any suggestions?
 
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Plumberboy76

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Joined
Mar 14, 2013
Messages
22
Location
Maryland
So both left and right cylinders move, could that still be the case? I was thinking inner piston seals but it doesn't drift any other time. I don't know enough about hydraulics to know what goes on with the check valves, valves spools. Could any of those things cause this situation?
 
heymccall

heymccall

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Feb 19, 2007
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5,379
Location
Western Pennsylvania
You said it will carry a load and not noticeably drop.
What if you pick the nose of the machine up with the bucket edge down. Does the machine drift down?
 
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Plumberboy76

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Joined
Mar 14, 2013
Messages
22
Location
Maryland
Very shallow pockets, if they were deep I would have just sent it into the dealer and waited for the the bill!! Anyone else have any ideas? I plan on having the machine down for a week at the end of June and would like to get it repaired then (if I can find the problem).
 
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Mark250

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Aug 30, 2015
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victoria,Australia
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heavy equipment technician
block off the lines going to one lift cylinder at a time and see what happens
if you can connect the rod end and piston of disconnected cylinder with a line to contain oil spillage
 
Mobiltech

Mobiltech

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Jan 14, 2014
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1,697
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Sask.
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Self employed Heavy duty mechanic
Could it have air trapped in the rod end of the cylinders. Try raising the loader arms all the way up and down to see if that makes it any better
 
Nige

Nige

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Jun 22, 2011
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29,379
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G..G..G..Granville.........!! Fetch your cloth.
heymccall said:
If someone can post a hydraulic schematic, we can see if there is a crossover over component, like a float valve, that may simply have a blown seal.
Click to expand...
Serial Number prefix should be B7H if it is a 257B3.
Problem is that there is a break at B7H01035 and the schematics are different above & below that. Need to know which group the machine falls into.
 
DMiller

DMiller

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Feb 21, 2010
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16,579
Location
Hermann, Missouri
Occupation
Cheap "old" Geezer
I fall into Mobiltech thinking, Air in cylinders, when lifting is already compressed, when back dragging could be a bubble that expands and compresses as the bucket rides uneven surface. Need to get the cylinders disconnected from the bucket, no load on them with fittings UP and cylinder level then drive full distance one way, loosen fitting on cylinder side with minimal Fluid in it, see if air escapes, tighten all fittings run cylinder full to stop other direction repeat the process. Farm tractors are notorious for this issue.
 
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