Welded VS Bolted hydraulic cylinder?

[joes_427_vette]

Renze;
I bought a used Kubota plow and frame to mount on my John Deere. To rebuild the cylinders I had to cut them with a bandsaw and reweld them. The local hydraulic shop said I wouldn't be able mto get them apart for seals. When I brought the pieces back for seal comparisons he laughed and said, " I see you found the secret to getting them apart. " I normally wouldn't have done this but without seals they leaked and would have been junk anyway. This must have been some Japanese engineering.

 

[Renze]

When I brought the pieces back for seal comparisons he laughed and said, " I see you found the secret to getting them apart. "

A hydraulics shop where i once been on behalf of my former boss, had a special bench to clamp and unscrew cylinder caps. They have a little notch in them, comparable as how you mount tapered bearings with a nut and special wrench.

When i rebuilt the cylinders of my loader (63mm, 2.5") my pipe wrench wasnt big enough, so i notched it with an angle grinder and tapped the head loose with a chisel.

On some cylinders, like the assister rams on a tractor 3pt hitch, have a small nut which you can unscrew. then when you shake it, there are a load of securing balls rolling out of this hole, after which you can easily take the plunger out of the cylinder.

I think the hydraulics guy was either pulling your leg, or just uninformed. He probably said that because he wanted to discourage you to generate some work for his shop, or he just wanted to sell you a set of new cylinders...

The 300 bar, 100mm diameter cylinders we build into the loaders at my daytime job, have the pistons screwed onto the rod with a tightening torque of 2200 N/m which is 220 kg/meter. I have no idea how much foot/pound this is, but its HUGE. The average 80kg person would require a wrench length of allmost 3 meter to generate this torque by his/her own weight...

We dont sell spare piston rod seals for them because there is no way a local shop could get the piston off the rod to take it out of the cylinder cap. We have piston rebuild kits, but when the rod seal leaks, you're going to need an exchange cylinder. The customer gets a rebuilt one and trades his old cylinder, for the cost of labour and seals. Once rebuilt (in the hydraulics shop we deal with) the cylinder goes back in stock for the next exchange customer.

 

[Wayne County Hose]

Renze;
I bought a used Kubota plow and frame to mount on my John Deere. To rebuild the cylinders I had to cut them with a bandsaw and reweld them. The local hydraulic shop said I wouldn't be able mto get them apart for seals. When I brought the pieces back for seal comparisons he laughed and said, " I see you found the secret to getting them apart. " I normally wouldn't have done this but without seals they leaked and would have been junk anyway. This must have been some Japanese engineering.

Can you take pictures of this cylinder and post? I have never met a cylinder I couldn't take apart without cutting it. Well, no, sorry. There was this one Yanmar loader cylinder one time. It was supposed to unscrew, but even heating the tube cherry red wouldn't loosen it, but that's another story. n