Drippy Cylinder (been rebuilt)

[Richard]

Wondering if you agree with my thought process.

Flexwing mower has two cylinders that change the height. Both were leaking & dead when I bought the mower. Couple weeks ago, I took one apart, took to shop (the rod/piston, the rest of it was at home) and they fitted new seals to it and gave me another set of seals to rebuild the other one when I got home. I also bought a new breather for them (old ones had been torn up)

Yesterday, got mower out to try to find the right height so I can put those height adjusters (donut things on the rod) to get a fairly workable cutting height

Turns out one of the cylinders is leaking (slow leak) from the vent. So I'm presuming one of the following:

1. The seals/gland on the piston got twisted, nicked and fluid is getting past it and leaking out
2. The seals they gave me are size "X" and I need a slightly larger more snug fitting size (although the OTHER cylinder does NOT seem to leak......yet)

3. Question....do the cylinder walls themselves wear down much where all the moving parts could be good but the walls have thinned slightly enough to make this happen?


My hydraulic fluid is something like $130'ish for a 5 gallon bucket so when I see it dripping out I see quarters falling out of my pocket. (it's not dollars yet)

I'll probably live with this for a while to see how much it really leaks but knowing how much that annoys me, I'll tackle it sooner or later.

Thoughts on above?

 

[oldnslo]

My first thought is seals got damaged on assembly causing the weeping.

2) could possibly be wrong size seals but suspect you would have seen this during assembly.

3) cylinders can wear egg shaped but more frequently the cylinder wall will get scored - scratched.

 

[LD1]

Im guessing either damaged on install, or scored cylinder wall.

With a "breather" it sounds like you have single acting cylinders? And the only time they are under pressure is when you lift the mower. IF thats the case, thats good news....because once you get the height stops set.....when mowing there wont be pressure causing leaks. Only when you raise the wheels for transport.

 

[Richard]

Sing acting is correct. This is why I'm not panicked about them. Most of the times the wings are down so as you point out, it's not a major issue.

I just want things to work correctly so that bugs me!!

When I had it apart, I attempted to peer into the cylinder. It was still mounted on mower and had hose attached so I couldn't get a fantastic angle on it....but I didn't notice anything obvious however, I know it doesn't have to be obvious.

There was crud in there from prior years of being ignored. Not that the cylinder was packed with crud.... just like old oil that had dirt/dust get to it.... turned it icky.

 

[Harry in Ky]

Yours is not an uncommon problem, I've seen it many times. Many of the cylinders used on such implements are actually double acting units with one port simply acting as a vent. The piston seals are often just an O ring with a couple backup rings, not a true piston seal. If you have installed new seals and still have problems with oil leaking by, look at the vent port and see if it's the same as the pressure port. It probably is, and you can simply add another hose to that port and use the cylinder as double acting. Then if the piston seals weep a little, so what? The leakage goes back to the tractor, not on the deck.

 

[Richard]

Yours is not an uncommon problem, I've seen it many times. Many of the cylinders used on such implements are actually double acting units with one port simply acting as a vent. The piston seals are often just an O ring with a couple backup rings, not a true piston seal. If you have installed new seals and still have problems with oil leaking by, look at the vent port and see if it's the same as the pressure port. It probably is, and you can simply add another hose to that port and use the cylinder as double acting. Then if the piston seals weep a little, so what? The leakage goes back to the tractor, not on the deck.

Ok, so I'll admit this angle didn't dawn on me at all!!

As I'm picturing this.... I have a single line connected to my remote. Goes to a T splitter and then goes to each cylinder.

(updated brain thought)

I was previously thinking how am I going to attach a single unit to the other port.... but it's just dawned on me I can do that with BOTH of them by simply adding another line and put another T splitter in there then they'd both be under similar pressure on both sides.

I've always loved this forum and again, I'm reminded why!!

 

[Harry in Ky]

See. You're smarter than you thought you were.