On my komatsu d41s3 I had a mystery leak on the hydraulic rank area. Turns out it is the tank itself. You can see where the fluid had washed away the dirt, I cleaned it and literally watched the fluid seep through the metal. I am guessing a hair line crack I cannot see. Is the only repair pulling the tank and having it welded Or do you think a good cleaning and epoxy might hold? I don’t think it is under any real pressure only return fluid. Seepage is right at the point of the red arrow
I would clean prep then JB weld in a thin line. After drying, clean light sand and another coat little wider. Repeat for at least 3 coats I repaired the transmission pan on my 955 some years ago and it's still good. Used acetone before each coat
That was what I thinking…drain the tank so it doesn’t seep, clean really well
That's also the reason the first layer is as thin as possible, so if there is a small amount of oil then first layer it will hold long enough to get the other layers on
Pic. is too fuzzy and too close up to tell what orientation the crack is. I don't know if it's on the bottom or not? If you can get at it, you could probably weld it. Would have to drain the tank and grind a bit of a groove in the crack. If the crack is on the bottom would be good to rinse the tank out with varsol or solvent to get most of the oil out. Then would need to heat all around the crack to burn any oil out that has seeped into the crack or could seep into the crack. The heat would hold back any oil from running into the crack. Pretty much the same technique as repairing a cracked hyd. line. It can be done but has to be perfectly clean of any oil to prevent pin holes.
Is explosion an issue of a drained tank?
No, it's oil not gas. You'd want to leave the fill cap off. You need to remove all signs of oil residue from the tank prior to welding.
Id probably try welding it as is... cause never mind pulling a tank
I cannot get to the spot to weld it without pulling it…I may could clean and epoxy it in place
You could try epoxy but you'd still need to clean it and make sure there was no oil residue seeping through. That would involve draining the tank and probably heating it some to get rid of any oil residue. They make stuff for leaking fuel tanks but they're more for temporary repairs until the tank can be properly repaired or replaced.
While a good weld repair would be the best and longest lasting. I would give AllDodge's idea a try. About all it will cost is some time and a couple tubes of epoxy. If there is anyway you could pull a vacuum on the tank while doing it that might help some. Not knowing the design of that machine maybe just connect a shop vacuum to the filler neck?
If the machine could be parked on an angle with the crack at the high point so any left over oil would run down from the crack may help. I think if you're going to try to repair it, it would be best to try and keep it free from as much oil residue as possible.
I can drain the tank easily, I think I will do that and see if I can get a small torch in there to burn the fluid away, then clean real well with brake clean…epoxy and see if it holds…muh job is getting in the way of my fun time tho