Need review on hydraulic hail Mary.

[amashinga]

OK, I will keep it to a hydraulic fluid change without flushing.

I am making fair progress, except for one cylinder that is pretty close to locked up. I wonder what I will find when I get it open.

Any preferences between ptfe and polyurethane piston seals ?. I seem to be able to get either for this application.

Thanks
Bruce

 

[Wayne County Hose]

OK, I will keep it to a hydraulic fluid change without flushing.

I am making fair progress, except for one cylinder that is pretty close to locked up. I wonder what I will find when I get it open.

Any preferences between ptfe and polyurethane piston seals ?. I seem to be able to get either for this application.

Thanks
Bruce

polyurethane

 

[Willl]

3. Its a minor irritation, but when the lift arms are fully extended and the relief valve goes, the bucket starts tilting slightly.

This almost sounds like a cylinder miss match. Are both left and right cylinders identicle ?

 

[amashinga]

They are, but it is the tilt cylinder that is partially locked, so I think the chances are good that when I resolve that issue, I resolve the creeping issue too.

What I mean by partially locked is that the cylinder will move, but I have to use a lot of strength to get it to move, even though all the fluid is drained out. Pretty much I have to put a bar through both ends and operate it like a double handled pump to be able to move it. When it moves, it jerks, so I know something is wrong there.

 

[Wayne County Hose]

What I mean by partially locked is that the cylinder will move, but I have to use a lot of strength to get it to move, even though all the fluid is drained out. Pretty much I have to put a bar through both ends and operate it like a double handled pump to be able to move it. When it moves, it jerks, so I know something is wrong there.

Maybe a problem, maybe not. You may take it apart and find everything normal.

 

[amashinga]

Next steps, and further questions

I have popped all the cylinders. 2 of the pistons look ok, one has a bad score and I may decide to replace it, and then the one that was sticking looks like it got used in a game of street hockey.

The seals show varying signs of wear but given that they are all really cheap, I think I will just replace them all anyway.

So here come the questions.

I cannot find a supplier for pistons. Is this something that you usually just take along to a machine shop, or can someone point me to a website ?.

The second and longer question, the seal catalogue I was looking at has tolerances listed for the OD of the piston as well as the bore diameter. Assuming a bore of 2.5 they usually indicate a piston OD of 0.004 below this. My pistons seem to be more like 1.490 even in areas that the milling marks are still visible, ie limited wear. Is 0.01 an acceptable tolerance in this application ?

 

[Wayne County Hose]

I cannot find a supplier for pistons. Is this something that you usually just take along to a machine shop, or can someone point me to a website ?.

Hercules Sealing Products You want the Cylinders & Repair Parts catalog.

The second and longer question, the seal catalogue I was looking at has tolerances listed for the OD of the piston as well as the bore diameter. Assuming a bore of 2.5 they usually indicate a piston OD of 0.004 below this. My pistons seem to be more like 1.490 even in areas that the milling marks are still visible, ie limited wear. Is 0.01 an acceptable tolerance in this application ?

Don't worry about it. But, if you are going to get 1 piston, you might as well get them both.

 

[amashinga]

Thank you Andy. I live in Canada but if it is in any way worth your while to ship the items and its something you deal in, just send me a PM.

 

[Wayne County Hose]

I don't stock this stuff and I would need your old ones in order to measure them. I would suggest locating a local hyd shop. Otherwise, you could ship them to me. Another suggestion would be to look in the Hercules catalog for a pair of cylinders that are close to the same measurements and go with new. By the time you buy pistons and seals, a new cylinder isn't much more and you have new cylinders instead of old junk.

 

[john_bud]

H&D Distributors, Inc. Your Complete Source for Seals

if you follow the link and down load the catalog you will become an expert. It's like 10 meg and includes pictures. Prices are ok, delivery in US is good. But, the understanding you get from comparing the parts in hand to the pictures is priceless.

jb