hydraulic cylinder rebuild

JOB · Jul 29, 2014

On this hydraulic cylinder I had one of the ports leaking. A half inch pipe thread fitting was put in a o-ring fitting hole. To weld a new one on I had to take the cylinder apart. Might as well rebuild it while it is apart.

On a piston as pictured when you buy a seal kit do you get the correct number of seals in the package or is there extra if your piston does not require as many as in the package. As you can see I have two extra, each side had three seals on it, and I had four in each package????

bison · Jul 29, 2014

Did you compare the thickness of old stack of 3 V-rings including the cover cone with the new set of 4?

Tvertiz · Jul 29, 2014

From what I have seen there is usually the correct number of seals if this is from a dealer. Now if it is from a hydraulic shop that put,together a kit for you I could see them messing up. I would look close to see if it was rebuilt wrong before you got to it. That being said if it was only the fitting that was leaking before I would go with what was there.

Steve@Advance · Jul 29, 2014

It's common to get extra parts in a seal kit. Some kits fit more than one application, sometimes there are design changes to the cylinder, sometimes there are design changes to the seals themselves.

You really just have to look at what you get and put it together as best as possible. If it doesn't look right, it probably isn't. Might give the supplier a call, see if they have any technical bulletins, or recheck to see if there are other possible kits for your cylinder.

The picture looks good from here...

Alan K · Jul 29, 2014

That looks like a "V-pack" seal kit. I had some replaced on a loader cylinder. I had the hydraulic shop put it together as they went in hard enough. I was worried about damaging them.

NCWayne · Jul 30, 2014

I wouldn"t be too worried about the extra rings, if three was all that came out. Like another post said, often these kinds of seals come prepackaged as a set, with a certain number or rings for the most common applications. If you have less, it's not unusual.

That said, if the stack height on the three soft seals, along with both the hard face and backer rings, is slightly more than the distance between the center and metal ends of the piston then you should be fine. You want the seal pack to be under just a little bit of compression in order to force the seal faces out and help them seal at lower pressures.

If you see the seals aren't tight with just the three then you may need to go ahead and put the forth ring in each side. If it is too much then you will have a hard time putting the piston back into the barrel of the cylinder because the extra height will cause the pressure on the seal pack to be greater than it needs to be, thus pushing the seals further out.

Beyond that, V ring packing is pretty much the simplest kind there is, so it's going to be hard to mess up. Good luck.

JOB · Jul 30, 2014

I bought the kit along with the wipe and gland seal
and a couple of O-rings at a hydraulic shop. I
figured when I showed them what I wanted they would
give me the correct part and no problem. Looks like
the kit fits in more than one cylinder.

JOB · Jul 30, 2014

I got this cylinder back in 1979 for a wood splitter I was going to build and have no idea what it came off of. So I could not go to a dealer. The stack of seals were in a sealed package.

As for being rebuilt wrong it was missing the flat ring that goes behind the O-ring on the gland. That gland O-ring was a little messed up but never leaked.

When I pulled the rod assembly out of the barrel there was little to no resistance so I thought I might as well put in new seals.

JOB · Jul 30, 2014

I should have looked at what I had before I started to put it together. I had it all together and the seals were so bulged I said you are never going to get this into the barrel. That was when I counted the parts and took one ring out of each side. Looks a lot better now but I would bet it will not be easy getting this back in the barrel.

JOB · Jul 30, 2014

I am going to lube up the seals real good but I am betting it will go together hard.

JOB · Jul 30, 2014

What you see in the picture is the piston ready to be put back in the barrel. The extra ring made the seals bulge too much and I thought it would be impossible to put the rod assembly back in the barrel. So I did remove the extra seal, should have counted first. Hope I did not expand out the seals that are still on the piston by compressing all of the seals when I tightened the rod nut down before I removed the extra seal. Should have it back in today if I have no problems.

hydraulic cylinder rebuild

JOB

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bison

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Tvertiz

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Steve@Advance

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Alan K

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NCWayne

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JOB

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JOB

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