lift cylinders jammed bobcat

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tictac

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Feb 29, 2024
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Hello, I'm seeking assistance regarding my S550 Bobcat skid steer. Initially, everything functioned smoothly with the tilt and lift cylinders, except for a leak in the right cylinder. However, after consulting Bobcat and having them replace the lift pistons and seals as they said pistons were so bad they replaced them both as they said both needed to be replaced together, I now encounter an issue where the lift cylinders fail to elevate, while the tilt cylinders continue to function correctly. I'm hesitant to conclude that the hydraulic pump is faulty since the tilt cylinders operate as intended. Could anyone provide insight into what might be causing this issue? Additionally, I verified the presence of hydraulic fluid by cracking the lines. They seam to be jammed up as I can see the lines moving when I try to opperate it.
 

brdgbldr

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If the actual pistons were replaced because they were bad, did they re-hone the cylinders?

If the pistons were ate up then the cylinders probably were also. So a new seal on a new piston would get chewed up by the bad cylinder.

You should be able to check this by using the bucket to tilt the machine up ( if the lift seals are bad you may not be able to lift the machine. The arms will just raise). Then see if the machine comes back down as the arms can't hold it up.
 
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tictac

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Feb 29, 2024
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If the actual pistons were replaced because they were bad, did they re-hone the cylinders?

If the pistons were ate up then the cylinders probably were also. So a new seal on a new piston would get chewed up by the bad cylinder.

You should be able to check this by using the bucket to tilt the machine up ( if the lift seals are bad you may not be able to lift the machine. The arms will just raise). Then see if the machine comes back down as the arms can't hold it up.
After inspection, he confirmed the cylinders were in good condition without any scuff marks from the pistons. However, he noted cracks on the pistons where the rubber seals are located at the ends, allowing rotation. Consequently, new pistons were installed. All lift seals were replaced, and new pistons were fitted on both arms. Despite this, once the arms were lowered, they remained immobile, unable to retract or expand. Meanwhile, the tilt cylinders continued to function smoothly without any issues. He said he never seen this before.
 

ByggareBobby

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Jan 3, 2024
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After inspection, he confirmed the cylinders were in good condition without any scuff marks from the pistons. However, he noted cracks on the pistons where the rubber seals are located at the ends, allowing rotation. Consequently, new pistons were installed. All lift seals were replaced, and new pistons were fitted on both arms. Despite this, once the arms were lowered, they remained immobile, unable to retract or expand. Meanwhile, the tilt cylinders continued to function smoothly without any issues. He said he never seen this before.

Are you referring to the pistons in the engine cylinders now or the rod in the hydraulic cylinder? I am a little confused.. ;-)
 
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tictac

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IMG_2063.png
 

Firefighter

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I wonder if the seals were damaged during installation, also they had a cushioned cylinder also , i guess
the pistons were a direct replacement, and not for a non cushioned or vice versa, not sure if that matters but i think
they use different barrels
 
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tictac

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Feb 29, 2024
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I wonder if the seals were damaged during installation, also they had a cushioned cylinder also , i guess
the pistons were a direct replacement, and not for a non cushioned or vice versa, not sure if that matters but i think
they use different barrels
The origional pistons were discontinued for the 2017 s550 and said to use the new version. Also it said that both needed to be changed at the same time which he did. The only diffrence between the the old and new pistons was an extra ring around the piston which didnt take any seals.
Then he also changed all the other seals with new ones. It doesnt make any sence as I said before the arms were lifting with no problems before untill he got in there and now they wont lift or anything.
1709301356367.png
 

brdgbldr

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Here's a longshot…. Is the manual lift release valve stuck open?
I'm talking about the valve that is opened by pulling up and twisting the red knob on the right side of the seat. I have heard of this happening.
 

billyb

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Oct 13, 2022
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Any chance you crossed the hoses on one side when installing cylinders? You could try disconnecting the hoses on one side and plugging them with proper plugs. Then try to lift loader This would tell you if you have a problem with that cylinder. If loader still doesn't function hook hoses up and repeat with the other cylinder. Note! If you have hoses crossed on one side loader won't function. One side will be trying to lift and the other side will be trying to lower!
 
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tictac

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Feb 29, 2024
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Hi guys so we ended up recalibating the lifts and after that it seam to work now everything is working properly. we checked it out and we noticed it wasnt going back to the nuetral state so once recalibrated everything worked
 
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