I'm wondering if anyone has had a problem with the hydraulic tank cracking on a Deere 135C RTS excavator. I have a customer's machine that had a leaking hydraulic tank. On the side of the tank facing forward there was a small pinhole leak but it was about 1/2 way up a 6 inch long verticle crack. The crack is about 1/2 inch in from the side of the tank. I vee'd it out going an inch past both ends of the crack and welded it vertical up with 6010 rod, 3 passes. They ran the machine 2 days, got it stuck and by the time they got it out, the tank was leaking again. The weld cracked in the same exact place as the previous pinhole. It is a square tank which is a little unusual in modern excavators but now I'm wondering if the tank is in a bind? Or if things are moving around a bit when the machine is used hard? I checked with a used parts place that had wrecked one of these machines and they had sold the tank and have not been able to locate another used one. This makes me think that others might have had this problem. Any thoughts? At this point I'll go back on Monday, suck the oil out and reweld it and maybe try to watch the tank while they operate the machine. Thanks.
Check for tank pressure relief. If relief is plugged, excessive pressure can work the metal and cause crack. Did you overfill tank?
Because the tank sight glass was unreadable it appears that the tank had been overfilled. Welded up the cracks, replaced the sight glass and refilled to the correct level. It has been operating now for a week without any more problems. Thanks dozer for the info.