cleaning up a hydraulic cylinder

[Oldtoolsnewproblems]

I'm a little sad to give up my 100% hand split status but a good enough deal turned up that now I am working on a log splitter project. I got a 5" parker ram that looked in good shape, brand new hoses and a pump, but when I got home i found the flys in the ointment, or more specifically the water in the cylinder. thankfully the pump and valve were mostly capped up and had oil in them. now the cylinder on the other hand had a good squirt of water in it, so i pulled it apart, it's the flavor with a plate cap and base. the piston is perfect, only rust on the threads, plating is mint, but the cylinder walls have long lines of light rust in the top 80%, and the pocket under where the piston was hanging out has a fair bit of rust and pitting. I'm gonna use this thing regardless, becasue even with plenty of bypass it will still make a decent splitter, better than a "10 ton" electric one that puts out about nothing.

so the question is whats the best way to clean up the cylinder wall. should I take a wire wheel to it or is that too aggressive? my gut instinct is a scuffy pad on a whizzer, but if even thats too much I could cap it and put a quart of evaporust in there and roll it over once a day for a week or two. I'm hoping the 4 castiron rings will be a bit more forgiving of the pitting than o-rings would be.

 

[sean donato]

Depending on exactly how bad it is it will need bored, or chromed to fix. If not all it will do is tear up the piston rings and seals. Bypass just gets worse with time amd use. A scotch pad should clean up the rust just fine. Pitting is going to be the problem, hopefully it's not too deep. The evaporust would be a decent idea too, I think.

 

[rancher2]

I would take it to a hyd rebuild shop and have them take a look at it. Barrel may just need honed out. If the chrome on the rod has pitting that's going to be a problem. If its repaired right you never touch it again.

 

[Oldtoolsnewproblems]

the rod is perfect for some dumb reason, but the pits on the cylinder are pretty dang deep. I'm gonna fill it with rust remover to get rid of the high marks, and put it back together with oil o preserve it. gives me tiem to decide what to do, a well as mockup the rest of the project.

 

[muddstopper]

Hard to make a recommendation without actually seeing the amount of rust myself. You mentioned cast iron rings which makes me think your odds are good that simply honeing out the rust and replacing the rings and seals and your cylinder will seal and work for years. If you can find, borrow or buy a ball brush hone, run it thru the cyl barrel until you have a good crosshatch pattern and reassemble the cyl.

 

[Oldtoolsnewproblems]

really is a cross hatch correct in a hydraulic cylinder? I used to build engines for a living so i'm full aware of the point and value of cross hatch in infernal combustion engines, but for hydraulics I am out of my depth, but intuition says smooth is better, since unlike an engine, anything leaking by is a lubricant, not an abrasive like air.

I put it together after doing 3 days of evaporust and rotating it every 6 hours. I only have part of a gallon of the stuff so I:could hardly fill it. looks miles better, I lightly honed the very worst of it to be sure there was no high points, but essentially put it back together as-is, aside from replacing a bad looking o-ring in the gland. I want to get this thing all mocked up asap, then I might send the cylinder out to get touched up later, after seeing how it works as is. for sure the evaporust took off all the high spots, very happy with it, if it werent for the water pitting at one end of the cylinder i'd bee %100 its good to use as is. I't salways hard to estimate pits depth, but they could have easily been .020 on the very worst of them, but most were under .006. I put the bad end at the end of the stroke, which with luck I'll be able to avoid using all together and make it a non -issue.

 

[rancher2]

If you are going to all the work to build a splitter around this cylinder why not take it to a hyd rebuild shop and have it done right and you will never touch the cylinder again. Tell them how you are going to use the cylinder and there are different seals they can install for a cylinder that is going to be stroked a lot. In the old days I resealed a lot of cylinders now days they go to town and are done right. If the barrel won't hone out to specs these is no use in using it.

 

[Sidecarflip]

I have a multitude of hydraulic cylinders on my farm equipment and if I get a leaker, it goes to the hydraulic shop for a rebuild, no exceptions. They have the tools and the knowledge (and usually the parts on hand) to do it right the first time and it's not all that costly either.

 

[muddstopper]

https://www.hemsltd.com/blog-hydrau...,is visible on the cylinder walls. More items

 

[muddstopper]

I will agree with those saying to take it to a shop that deals with rebuilding cyl, but only up to a certain point. Hyd cyl are not that hard to rebuild, but if you dont have the tools then letting someone else that does have the tools is the best and probably cheapest way to go. One thing I know about my area is that none of the folks around here owns or has access to a honing machine. What this tells me is that most likely those folks offering rebuilding services cant really do a better job that I can in my own shop. Not knocking what those rebuilders are doing, most of them dont focus or specialize in rebuilding hydraulic cylinders. And not knocking the folks that use their services because to a lot of them, taking the time to tear down a cyl, order the parts and re-assembling the cyl isnt something they have a lot of time to do themselfs. My personal opinion is that if you have the ability to tear a cyl down and put it back together, then unless you are expecting a perfectly working cyl and plan on replacing the cyl barrel and piston, then I would just do it myself and live with the results. Pits in cyl walls caused by rust will wear out seals faster than a smooth bore, but with cast iorn sealing rings, Its something I could probably live with.

 

[muddstopper]

There is always this option. https://www.surpluscenter.com/Hydra...Hydraulic-Cylinder-Monarch-647969-9-12098.axd

 

[Oldtoolsnewproblems]

the sad thing is I have a very nice Sunnen cylinder hone but the larger mandrel got stolen, and even if it hadn't been, it doesn't have the travel to do the whole cylinder.

 

[Oldtoolsnewproblems]

this was great, thanks! I've read like 20 vendors ad copies for either their tools or honing services, but all of them just keep saying things like "honing is really improtant" and "make sure you get the correct surface finish" but none i could find gave actual numbers. judging by that, smoother is better, as the only point against 320 or finer grits is that it is ineffecient, not that a mirror finish is a bad thing. I have some 400 grit flexi-hone stones as well as the normal coarse one so fluff and buff will happen. fun hack for a final polish/knock down high peaks which is much more important in motor cylinder finishing is to wrap the stones in a red scuffy pad and run that in there with plenty of fluids, and it will buff the micro high spots while not really removing any material. the other hack is if you don't have a fine enough stone is to not flush your fluid as fast and let teh grit build up, this actually results in finer cuttting, not more aggressive. at least when you are using real honing oil or motor oil as a lube. if you use wd40 or somethign super thin you may not get the same results. I used to use an ATF/wd-40 mix for my final hone as the thin coolant removes grit and swarf from the bore much faster, but it does make that final cut a bit more aggressive so its all about balance and understanding the requirements of the job.

 

[Oldtoolsnewproblems]

also as a side note, since I know random strangers will likely stumble across this thread 5 years from now trying to do the same thing: this is a parker 2H cylinder, with the 4 long tie rods holding it together. those are 100ksi min yield studs, so they are not as strong as you might expect, likely to keep them ductile or whatever, but they are more like a grade 5 bolt, grade 8 is 120ksi proof, vs 85ksi on grade 5. this means torque spec for these should likely be around 350psi with lubricated threads. be super careful putting an assembly like this together to make sure all bolts are balanced and drawn up evenly, you don't have junk in your surfaces etc etc but that should be clear. all those numbers are for my bolts, which are 7/8-14, numbers change with different bolts but I would assume most all log splitter sized cylinders use the same rods. thank god for rolled threads.

If you wanted to be a total nerd about it, which is unneeded but since i have the ref in front of me right now I might as well write it down, the pre-torque on all 4 studs should be about 100ftlbs torque before going to full weight. Final assembled preload is about 65 tons of force, with a yeild of around 100 tons best case, which we all know we will never get outside the lab.

now to be the opposite of a nerd, those numbers are slightly concerning as my impact was able to remove these bolts (I think, christ I already forgot) and my impact is advertised 650 ftlbs, but i was on a long air line and there is NO WAY it puts out 650, i was even using an adapter at the time. But who knows, previous owner may have had it apart once, maybe I got lucky, maybe I hit teh resonant freq of the studs, maybe some other made up reason is the answer.