843 hydraulic leak problem

[ajwgator]

Hi guys, all is doing ok here in Kentucky execpt for the drought! Its been some time since I have been here since all has been going pretty good with my 843. Well until now... I developed a hyd leak on the retract side of my right lift cylinder the other day. I felt certain it was the hose since is seemed to be seeping pretty good at the lower end of it inside the engine compartment. I had one made, changed it, also discovered the extend line to the same cylinder in the engine compartment was chaffing two lines also. I removed it (line from the control valve to the extend hyd hose), rerouted it properly, and got my machine all back together.
Checked the hyd fluid, wasn't showing on the stick, added 2 gallons of John Deere hyd oil and started it up. I let it run for about 5 minute, ran the lift and tilt through some but didn't they didn't want to come back to neutral. I got out and was checking for leaks after my repairs. I found the fluid leaking from the back of the same cylinder into the engine compartment still. I shut down with the bucket lifted about 1/4 high, and tilted down almost full. I just assumed (you know what that means) I had a little bit more air in the system than I anticipated since I had both sides of the cylinder opened.
My lift cylinders are the old type with welded lines. I discovered that the retract line on the cylinder was not secured to the back of the cylinder. It looks as though the weld had been ground off for some reason either to repair it or change the hose like I had just done. I didn't remove the cylinder to change the hose. Anyway the line appears to have been brazed before and it is leaking at the bottom side where it would have been normally welded to the cylinder. I guess I will have to remove it and get all the oil out of it to braze it again. Has anyone ever tried to braze a leaking line on the cylinder with it still installed on the machine? I want to try it but not too sure if I can get enough oil out of it since it can't be removed from the cylinder.
Thanks for any input. Jay

 

[sterlclan]

welding with fluid in the cyl is a bad idea hard to get the heat right best to remove it and fix on the bench just my 2c Jeff

 

[Tazza]

welding with fluid in the cyl is a bad idea hard to get the heat right best to remove it and fix on the bench just my 2c Jeff

I have to agree, pull the cylinder off the machine and extend it all the way forward so you don't cook the piston seal. Give it a good clean, a wire buff works well here. Then re-braze the joint.
You said it looks ground, you are talking about the joint for the fitting? i have seen them wear on the sides where the base is welded on that has worn through the welds and caused it to leak.

 

[ajwgator]

I have to agree, pull the cylinder off the machine and extend it all the way forward so you don't cook the piston seal. Give it a good clean, a wire buff works well here. Then re-braze the joint.
You said it looks ground, you are talking about the joint for the fitting? i have seen them wear on the sides where the base is welded on that has worn through the welds and caused it to leak.

Jeff & Tazza, I'm sure your both right. I will take the cylinder off the machine to do it properly. After I got it started again, its defenintly leaking from the line itself. Its not where the line is brazed into the cylinder but in the middle of the line itself. This line runs from the front of the cylinder to the back where it connects to the hydraulic hose. About 3/4 ways back the line is suppose to be welded or brazed to the cylinder body to keep it from vibrating and moving during operations. Someone in the past has cut this weld apart and it is no longer secured to the cylinder. It is at that area where the line was secured that is leaking. The cylinder has a few grind marks in it but its not leaking. I really don't know why someone would have to cut that with a grinder like they did, but I will have to deal with it now. I have them clamped together now with 2 Adel clamps, one around the cylinder and one around the line to stop it from moving.