Cleaning Hydraulic Cylinder Piston Rods

[boofi]

Good afternoon,

We have a few large hydraulic cylinders controlling loading arms for loading ships at a terminal. These cylinders are subject to a harsh environment of salty air and as a result the rods are prone to small pits and some corrosion. I believe they are hard chrome plated. One of the OEM recommendations is to periodically clean the rods. I am trying to add this to our PM among other things. What method do you recommend for cleaning the rods? Emery Cloth and some oil, scrubbed circumferentially? Some kind of solvent? Additionally, after cleaning, is there some kind of protectant coating we can add every PM to help slow any further corrosion?

Thank you.

 

[3DDave]

I expect emery cloth will soon lead to replacing the rods and the rod seals.

The OEM should have specified.

 

[boofi]

Yes the OEM didn't specify a method, among many other things they didn't provide. The corrosion we have has already caused damage to some rod seals and wipers leading to significant loading arm downtime. I only found the Emery cloth and oil method with my google-fu, as I don't really have a "hydraulics" person to turn to. Even our 3rd party vendor isn't very helpful outside of trying to sell us their service. I expect any kind of abrasive method (scotch brite, sandpaper, emery cloth, etc.) will potentially be damaging to the rod. I know I've personally used a type of non-scratch scouring pad that does not contain aluminum oxide for working on my car. I suppose something like that would reduce the risk of damaging the rod but obviously be less effective. We could initially try lint-free rags and solvents. Would solvents harm the chrome coating?

The other thing I'm trying to encourage our operations group to do is to exercise the arms through their full range of motion at least once a week. I am hoping that allows the piston rods to cycle through the wipers, and to circulate any dirty oil through the reservoir and filter.

EDIT: I've also had another thought. The rust build up is a probable indication of the chrome coating failure correct? Is there any way to re-chrome or protect the rod in place? We would have to do this regardless of the method of rust removal; mechanical or chemical.

 

[hydtools]

Is there space to install rod boots to protect the rods?

Ted

 

[PNachtwey]

I would use WD-40. It was meant to remove rust. I wouldn't use anything abrasive. If the rod is pitted you can live with it or you may need to replace the rod which may be an almost impossible task.
If you retract the rod when not in use it won't be exposed to the elements.

Peter Nachtwey
Delta Computer Systems

http://www.deltamotion.com

http://forum.deltamotion.com/

IFPE Hall of Fame Member

 

[TugboatEng]

Cleaning should involve rinsing the rods off with fresh water to remove salts.

Hard chrome doesn't provide good corrosion protection. For marine applications a layer of nickel needs to be plated on to the rod prior to chroming.

Minor pitting can be grit blasted and filled with a metal filled or abrasion resistant epoxy.

 

[boofi]

Thanks everyone! I will specify Solvent and lint free rags to try cleaning the rods. Rod boots are also a great idea to help protect.

Some of the rods are not able to be stored in the retracted position, annoyingly.

 

[TugboatEng]

Rod boots can trap water and exacerbate the problem. Leaving the rod open where it can be easily rinsed with fresh water is likely best.

 

[SwinnyGG]

You really need to specify the fresh water rinse that others are mentioning as well.

You need to apply a solvent which will dissolve salt; the best solvent for salt is water.

 

[Jacc]

It has been mentioned twice before already in this thread but I'll say it again:
FIRST, Rinse the rods properly with clean water to remove the salt, THEN wipe them off, THEN apply your choice of oil to prevent rust.
What type of oil you use is not AS important as rinsing and wiping off the first.