FEL Hydraulics worse than ever

Help please! I am getting really frustrated by the hydraulics on my SH's FEL.

The two cylinders worked and would lift the loader, but both leaked badly, so I replaced the big O-ring at the plug end, the little O-ring at the other end, and the 3 or 4 smallish rings that go on the cylinder (sort of a nested set of dust rings, I think).

New fluid, NO load on the cylinders: I could get the cylinders to extend sloooowly. They barely retracted at all. I figured it was air, so I dropped the front linkage ends to the floor and filled some more. Got a little better extending, but still not retracting. All with no load.

I could manually push them in when the tractor was off, with some effort.(The filler cap was off for this). Figured I"d avoid getting them stuck at full extended position again so I hooked up to the FEL. Now the system doesn"t have enough ooomph to lift the FEL at all.

I cracked the front (linkage) hose attachment and tried to lift. Sure enough, oil spurted out all over the place at high pressure.

So at this point, I"m wondering about the two rubbery cupped fittings at the base of the piston. They guy at the shop said they looked ok, but it seems to me that they must be letting oil flow by into the cylinder.

Is it possible they dried out over the week I had it all apart? The darn thing worked before I started on this mess (aside from the leakage).

Or is it air in the system? How can I bleed it if they won"t cycle in and out??

Given the high pressure oil when I cracked the hose connections, I"m leaning towards the rubbery cupped things, which I suspect should seal tightly against the outer cylinder housing. I"m kicking myself for not replacing them, but the hydraulic shop guy said they seemed ok to him.

Any advice before my next oil bath? Thanks!

you didnt say if the cycls are two-way or single as the H has one way hy system.

The "rubbery cupped things" ARE your cylinder seals. :>)

Allan

Allan, That's what I sort of figured. The rather taciturn guy at the counter (and it's a hydraulic shop!) said, "oh, those are just to guide the cylinder, no need to replace those."

So, I didn't replace them.

Color me irritated. And yes, "rubbery cupped thing" IS a technical term

Hi Gene, it's 2 way. Thought I got all the details in but I guess not.

You will have oil on both sides of the cyl if you have a double acting system.

Two way = pressure up AND pressure down.

Typical loaders around the time of the SH were ONE-way. Pressure up, gravity down.

The upper ends of the large cylinders were often used as hydraulic reservoirs, with the oil just flowing freely back and forth into the hydraulic tank on the SH.

If you've got a period-correct loader, and high pressure on the "retract" side of the cylinder, you likely have one of two issues:

1. Piston seals blown.
2. Hoses hooked up wrong.

Most likely you have single action cylinders. They come basically 3 different ways.. 1. cylinder rod is full size of the bore , so no oil or dead air space above the piston seal...2. rod is somewhat smaller than the bore and there is a breather on the top end and air flows in and out as the cylinder is cycled and 3. as mkirsch indicated, there is no pressure, but that space is used to hold fluid so the reservoir level does not vary so much, in which case there should be a low pressure hose attached to the upper (rod) end.
Long cylinders are notorious for holding air and it takes a while to get it all worked out. One reason is when retracted to ground level, the cylinder is usually not retracted all the way. run the front wheels of the tractor up on something so the cylinders retract all the way and see if that helps.
BTW, the cup things are the pressure seals, the things he gave you are the parts that center it in the bore and prevent metal to metal contact, piston to barrel.

I had an m do that. Had live pump and two way loader cylinders. Pressure seal gave up the ghost in one cylinder. Loader did not want to go up or down without a lot of effort. Had the cylinders rebuilt and wha la, worked fine.