Johnson Horizontal Band Saw rebuild...help?

[braddd123]

Ok guys after years of frustrating crooked cuts from chinese metal saws and just dealing with the noise produced from my chop saw I finally found the band saw I've been looking for. Its a Johnson(now Dake) horizontal band saw model "R". It needed some serious help, which I never mind doing for a good US tool, but it was all there. Theres two problems I'm running across:
1. I'm having trouble locating a manual for this model. Only one I've found is the recopies on ebay for 15$, just wondering if anyone has a pdf for one.

2. The bigger problem, I took the hydraulic cylinder that controls the down feed apart to clean up. It was working before but was very ugly and leaked fluid. After cleaning it up I noticed the gasket that lined the very bottom between the cast iron base of the cylinder and cylinder tube was worn out and I believe there should be one matching on top between the top and top of cylinder tube which wasn't even there. I cut two new rubber gaskets out of flat plumbing rubber from home depot because I don't know of any place that would have new gaskets for this cylinder. I placed the gaskets between the base/cylinder tube and top/ cylinder tube. Now I cant figure out how to refill the cylinder? First I tried the little filler on the side but after that little cup fills up in just sits there. If i extended the cylinder shaft the fluid is sucked in but then when the shaft returns the cup fills up again. I didn't want to take the cylinder apart as I have to make new gaskets each time I pull it apart so I unscrewed the top knob that controls the lowering rate of the cylinder and filled the fluid through there. But now the cylinder will not adjust on the lowering rate like it did before.
I will admit this is my first time having to deal with a hydraulic cylinder so I'm totally lost. Anyone have an idea how to fill this cylinder? where to possibly pick up new gaskets? if there is supposed to be a gasket between the top of the cylinder tube and top cap?

 

[jallyn]

If the one seal you made works well that should be enough...no need for two.

Use gravity since air is less dense than hydraulic fluid. Slowly pump hydraulic fluid into the lower port with the top port open to let the air out. Hold the cylinder horizontal with both ports facing up. Move the pressure line to the other port and flip the cylinder over and repeat to let air out of that end. Repeat over and over again, even letting fluid out to make sure you get the last air bubbles out, effectively bleeding the cylinder on both sides. Only when you are happy with the clear fluid coming out of both sides install on the machine.

 

[braddd123]

Ok there is no line on the exterior with a check valve or anything. The one port is that little cup with the top flap. I'm going to try and get better pictures tonight of the cylinder.

 

[jallyn]

OK. I was thinking of a standard double-acting cylinder. More pictures would help.

 

[braddd123]

Ok so here are some pictures I just took taking the cylinder back apart. The knob I painted red is the one you turn right or left to slow down or increase the lowering rate of the saw. Its connected to a shaft that runs down the center of the hydraulic piston shaft and at the tip its pointed like a needle valve that runs in the center of an atomizer on an old carburetor. The little cup on the side is the only exterior port to fill from when the cylinder is assembled other than the center of the piston shaft. the gasket shown is the one I made and you can see what happens everytime I have to disassemble the cylinder, its cut into pieces. There is also one between the cylinder pipe and the base which I also have shown. The bottom one was present when I first took the cylinder apart but the one on the top was not there. So to me it only makes sense that there should be a gasket between the top and the cylinder tube to match the base.

 

[braddd123]

last couple.

 

[paulsomlo]

Here's a manual of another Johnson model: http://vintagemachinery.org/pubs/4162/5253.pdf. They don't show any gasket in that application, which doesn't surprise me. It's common in the design of hydraulics for floor jacks for the tank seal to be metal on metal, relying on good fitting parts with huge amounts of torque to make a seal. When you torque down those three rods, I think you just end up cutting through any resilient gasket anyway. And I'm wondering if the top gasket was obstructing the flow of oil from the cup into the cylinder. I would say, clean things up, get all the oil off of the mating surfaces, smear a very thin layer of anaerobic gasket sealer on the edge of each end of the cylinder, then reassemble. You might run a pipe cleaner through the cup, just to make sure there are no obstructions.