Theres a crack in the weld at the end of the boom cyl. Whats the best way to repair? Can it be re welded on the machine?
What I read on that is to remove the ram/piston, grind out the old weld and then reweld. Removing the boom cylinder should not be to hard. Reason I would is that once you weld, there is a very good chance you will burn the oil inside the cylinder.
My SuperL boom cylinder cracked in the same spot and had been rewelded before we bought it. They didnt do a very neat job and it seeps a little. We are getting ready to pull it and take it in to get welded right. I called ESI in Columbus OH thinking I could get a used tube at a reasonable price.... I think they wanted $1200-$1500 for a used tube!! I will have mine rewelded.
Mine was also rewelded sometime before I got it. A couple hundred hours later I developed a tiny leak. I patched it up with my 110 mig welder. 10 hours later leaked again, patched again. Short while later it was leaking again. This time I drained some fluid and got the grinder out. I worked in areas about 1.5" long, grinding old weld out and creating a grove. After it was all done, I continued all day (left time to cool between welds) to weld more. My final weld bead is about 1.5" wide and 0.5" thick. Shortly after I discovered my rod to piston nut was loose, took it apart and the nut was only on about 3 threads. The slop could have been why my weld was cracking. Every things held up so far and that was 700 hours ago. I'd take it off, drain all oil and clean. Remove rod and piston or make sure cylinder is extended, as to not damage seals. Cover all important areas. Grind and clean, but not so much eye falls off tube. Stick weld. Let air cool and flush cylinder a couple times. Put back on. I'm no expert, just my own plan if it happens again
Very common problem - I always strip the cylinder. Which ever method you use, the original weld must all be completely removed & the barrel rewelded all the way round. When removing the old weld you will find the crack travels for some way under the visible cracked area. You can grind out the old weld, however, gouging with oxy or arc, or by machine shop lathe, is far more efficient.
I had the same problem when I bought my 580 SL 2.I removed the cylinder,drained the oil,but did not disasemble.I moved the rod all the way out and ground out the crack and then heated it up with the torch to burn out the oil and then welded it with my 200 amp Miller mig.So far no leaks.I have never had any luck welding with oil in the system.You always end up with a pin hole.I pefer using the mig in the spray mode than stick welding and have made cylinders from scratch with no problems.
Done similar repairs to various cylinders. As said, the best way way is to fully strip, gouge and arc it up, full radius. That said, I've had good results repairing cracks when the cylinders are still on the machine. It's important to ensure the hyd tank is de pressurised, and the gland inside the cylinder is at the other end to where you intend to weld, obviously rest the implement and allow oil to drain out of the ports. To wrangler; re pin holes from oil being in the system, I could that sticking the crack, real hot, 65% (give or take) (driven from a 300amp Mosa) burns all the nastys out making a nice weld.
It looks like I have a swing cylinder that is leaking that could have a crack. I will have to clean the area after I pull the floor plate to see what is what. Then again, I might just wait till I finish the work I'm doing. Being so wet, All I need to do is just stack trees to burn at this point. The dirt work from digging will have to wait to level out once it dries up some. That will be a good time to address a bunch of problems on my hoe.
The biggest problem with the cylinders was not just the crack between the base cap and tube. Look carefully for fractures in the eye/mounting pin hole. These cracks can cause the eye to fracture and drop the boom suddenly. A good hydraulic shop can machine the cap off the barrel and reweld. The cost here in Canada is about $300. If there are cracks in the eye/mounting hole for the pin they will not weld them. Some of the caps had an O Ring on them so even burning off oil would not completely burn the O Ring up and you still end up with pin hole leaks.
I talked to a guy today that said he's been working on these machines for 25 years. He said he's never seen a weld hold up for more than a year no matter how good of a job was done on it. He recommended getting a new tube and cap "made"?? Anyone have any experience with doing this? Thanks for the heads up about cracks in the pin boss. Ill look at that.
I've welded on PLENTY of cylinders... On or off the machine... Yes you need to gouge out the crack.... Heat helps you follow it... If it's oily.... Use a 110 mild steel rod to seal it... The rest with 7018... Your results may vary... Success: it comes in CANS . . Gotta Fly... Mike & "Jaz" the Flying Dogz . .
Oooops, I can't edit it... I meant 6010 to seal it... Then 7018
I've had this problem on a couple backhoes. The most effective repair was removing the cylinder, extending the ram, V grinding the entire circumference of the cylinder, heat the V grind with a torch to remove all fluid residue then having a good welder build the weld up in stages. Once that's done make a strap about 1" wide and about 1/4" thick that will fit over the weld, shape it to fit the cylinder then slowly weld it in place completely around the cylinder. The strap strengthens the repair area as well as the entire circumference of the cylinder. The last time we did this was about 8 years ago and I still have that backhoe.