Leaking tilt cylinder

[oldcarguy]

I have a Gehl 3635 one of the tilt cylinders is leaking through the weld under pressure, is there any tricks to passing a bead of weld over the leak, other than cleaning it well. should i disassemble the cylinder.

 

[bobbie-g]

I'm no expert here, but here are my thoughts. I assume you are talking an arc welder. Oxyacetylene will get it way too hot. I would guess a stick arc welder will probably do the same. Not sure if a wire feed turned way low might do the trick. Too much heat will char the oil on the inside of the cylinder, if not blow a line open because of boiling the oil (that happened to a guy with a torch heating up my backhoe, he blew a nearby line open, went off like a shotgun). It will also fry any seal or o-ring that happens to be too close to the weld site. I know you don't wanna hear it, but I'd sure not take a chance on either putting charred oil in my system, or blowing a hydraulic line or hose out because of excess pressure build-up from heating/boiling the oil. You do have a closed system there, and heat could cause a rapid and potentially catastrophic pressure build-up. I'm not sure where the relief valves are and whether they'd release the pressure, but you still have the charred oil problem. I'd disassemble the cylinder. ---RC

 

[oldcarguy]

I'm no expert here, but here are my thoughts. I assume you are talking an arc welder. Oxyacetylene will get it way too hot. I would guess a stick arc welder will probably do the same. Not sure if a wire feed turned way low might do the trick. Too much heat will char the oil on the inside of the cylinder, if not blow a line open because of boiling the oil (that happened to a guy with a torch heating up my backhoe, he blew a nearby line open, went off like a shotgun). It will also fry any seal or o-ring that happens to be too close to the weld site. I know you don't wanna hear it, but I'd sure not take a chance on either putting charred oil in my system, or blowing a hydraulic line or hose out because of excess pressure build-up from heating/boiling the oil. You do have a closed system there, and heat could cause a rapid and potentially catastrophic pressure build-up. I'm not sure where the relief valves are and whether they'd release the pressure, but you still have the charred oil problem. I'd disassemble the cylinder. ---RC

I planed on taking the cylinder off so i could drain it, also to not have any oil residue near my weld. I will go further as you suggested and disassemble the cylinder.

 

[jerry]

I planed on taking the cylinder off so i could drain it, also to not have any oil residue near my weld. I will go further as you suggested and disassemble the cylinder.

You will have to take it apart and then grind down into the leaky spot. You really have to get all of the oil residue out to get a good weld. I just had one fixed and the welder said old cylinders are sometimes hard to reweld because of oil trapped in the little cracks and so on in the original weld unless it was perfect which it wasn't or it would not be leaking.

 

[Tazza]

You will have to take it apart and then grind down into the leaky spot. You really have to get all of the oil residue out to get a good weld. I just had one fixed and the welder said old cylinders are sometimes hard to reweld because of oil trapped in the little cracks and so on in the original weld unless it was perfect which it wasn't or it would not be leaking.

I have done a repair like this before too. Remove the cylinder for access, drain the oil and as jerry pointed out, grind into the crack then weld over it. If the crack is at an end where there are no seals it will be fine, pull the poston out of the way and weld. If its at the end where the gland is, you will need to pull the ram apart as you WILL burn the O rings.
I personally have not had a problem with burning oil when welding a cylinder with oil residue in it, but i can see it happening. As stated too, the oil MUST be drained, if you hea it, it will have no where to go and will spray out of the crack or blow out somewhere else.

 

[skidsteer.ca]

I have done a repair like this before too. Remove the cylinder for access, drain the oil and as jerry pointed out, grind into the crack then weld over it. If the crack is at an end where there are no seals it will be fine, pull the poston out of the way and weld. If its at the end where the gland is, you will need to pull the ram apart as you WILL burn the O rings.
I personally have not had a problem with burning oil when welding a cylinder with oil residue in it, but i can see it happening. As stated too, the oil MUST be drained, if you hea it, it will have no where to go and will spray out of the crack or blow out somewhere else.

I welded a new fitting on my backhoe attachment cylinder and its been fine since. Just used mig. You can't weld up a sealed vessel though, that don't work it has to be vented.
I would just grind a notch through the leak, extending past the problem area, preheat the area to burn off oil residue then make a pass ot moderate temperature to insure decent penetration without burn through. Then subsequent passes to cap it off. If seals are too close to the area you will need to pull the cylinder apart.
Ken