MX5800 Lift Arms Won't Raise

scatman

New member

Equipment
b2601 mx5800
May 21, 2026
10
1
3
Sacramento
I just removed the hydraulic Cylinder case to change the lift arm shaft and replace the o-rings and I put it back together and now the arms are not lifting at all? Any idea what the problem can be?
 

Caden

Active member

Equipment
1979 B7100
Apr 16, 2026
193
95
28
Virginia
My first guess would be trapped air.

My second guess it that when you reassembled everything, the piston/rod is out of time with the lift arm. As in not aligned on the spines correctly.

@North Idaho Wolfman is probably the guy you most want to hear from in this case.
 

TheOldHokie

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L3901/LA525, G2160/RCK60, G2460/RCK60
Apr 6, 2021
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windyridgefarm.us
I just removed the hydraulic Cylinder case to change the lift arm shaft and replace the o-rings and I put it back together and now the arms are not lifting at all? Any idea what the problem can be?
Trapped air has absolutely nothing to do with it.

My first guess is you have the rockshaft arm/pushrod out of whack. Another possibility is the feedback and position control linkage is fubared.

Dan
 

scatman

New member

Equipment
b2601 mx5800
May 21, 2026
10
1
3
Sacramento
My first guess would be trapped air.

My second guess it that when you reassembled everything, the piston/rod is out of time with the lift arm. As in not aligned on the spines correctly.

@North Idaho Wolfman is probably the guy you most want to hear from in this case.
I double checked the spline with the dot and aligned correctly.
 
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TheOldHokie

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L3901/LA525, G2160/RCK60, G2460/RCK60
Apr 6, 2021
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windyridgefarm.us
No it does not
If you hear the relief activate when you pull the rod the position control valve is opening and the hudraulic system is deadheading. That means you have pressure to the valve.

If the lift does not come up the piston is not pushing on the rock shaft lever or you dont have pressure to the piston. What if anything did you do to the valve?

Dan
 

North Idaho Wolfman

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
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10,781
113
Sandpoint, ID
Take a couple pictures of the linkage and arms on both sides.
 

scatman

New member

Equipment
b2601 mx5800
May 21, 2026
10
1
3
Sacramento
If you hear the relief activate when you pull the rod the position control valve is opening and the hudraulic system is deadheading. That means you have pressure to the valve.

If the lift does not come up the piston is not pushing on the rock shaft lever or you dont have pressure to the piston. What if anything did you do to the valve?

Dan
We didn’t touch the valve, that’s why I’m so confused
 

TheOldHokie

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Equipment
L3901/LA525, G2160/RCK60, G2460/RCK60
Apr 6, 2021
12,299
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Myersville, MD
windyridgefarm.us
Move the lift arms to push that rod as far in as possible and take a picture of the lift arm position in that state.

Why did you take this apart in the first place?

Dan