Boom cylinders removed, repacked…slow and out of synch

[MJE]

I removed my boom cylinders and had a professional shop rebuild them. During the process of install I connected both cylinder bottom pins and all hydraulic lines. While Both cylinders were laying across a beam, I went to extend the piston(s), one piston was noticeably more responsive than the other. When the faster piston reached its limit the other, slower one, became noticeably quicker. Thoughts on why this would happen? Is it air trapped in the cylinder? How do I get both cylinders equally responsive?

 

[Delmer]

Could be one seal is slightly tighter, or has more oil, or less oil. Could be the hose plumbing gives one more oil pressure or less oil pressure. Doesn't matter, they'll never move the same until they're on the boom. As long as they both move the full stroke, put them on and run it.

Good idea to move them with no load like that to bleed the air out before you put a load on them, air burns oil.

 

[Jonas302]

Once you hook them up they will work normally the one with the least resistance even if its a tiny tiny bit less friction is going to go out first as they are not valved to be balanced but designed to see the same load on each one

 

[MJE]

Thank you both for the response.

 

[Delmer]

Actually, the most important thing is probably sliding friction vs breaking loose, once the first cylinder starts moving, it will keep moving much easier than the force to start moving.