Welding on Hydraulic Cylinder OK without disassembly

[rich_ncal]

One of the two Hydraulic fittings on my log splitter hydraulic cylinder broke. The fitting cracked in the threads for a hydraulic line connection and the end broke off. The other end of the broken part is welded to the hydraulic cylinder

I am planning to grind off the few remaining threads and have new part with threads welded on. This weld would be about 1.5 inches from the cylinder body.

Is it OK to weld on this connection without disassembly of the hydraulic cylinder? Is this a common way to do the repair this? Is there any danger of fire or damaging the cylinder?

 

[Cat_Driver]

Disassembly is always best.

 

[radman1]

I have welded with the cylinder assembled. I extend or retract the rod to get the seals as far away from the weld as possible. You could wrap cold, wet towels around the cylinder to pull some of the heat away. I have done that but not sure if needed. You can also weld part way, let it cool and weld again.

 

[tommu56]

Let it cool before you move piston back to "hot" area so you don't melt seals


tom

 

[Wayne County Hose]

I have welded with the cylinder assembled. I extend or retract the rod to get the seals as far away from the weld as possible. You could wrap cold, wet towels around the cylinder to pull some of the heat away. I have done that but not sure if needed. You can also weld part way, let it cool and weld again.

I have done it this way many times with never a problem.

 

[Leejohn]

Try this before you go to all the welding route. Get a screwdrive that just starts about 1/4" and tap it in until just good and tight. Don't hammer it real hard, now get something to unscrew the NPT while pushing on the screwdrive real hard. Don't use a easyout. Has worked for me many times.

 

[rich_ncal]

"Disassembly is always best." was a good answer in this case. The welding was just to close to the seal on the hydraulic line.

After it was all together the seal leaked. The seal and the back up ring for the seal at burnt from the welding.

So now I know how to get to the snap ring and pull the seal.

I don't have new seals yet. Any special tricks to install the new seal? Should be easy to put the seals on the cylinder head. I just wonder how easy it is to push the assembly with new seals past the groove for the snap ring.

(Photo of the welding attached).

 

[kennyd]

Seals are easy, just lube them up with some hydraulic fluid to help them slide in. I have also used some brass shim sheet material wrapped around the seal to help the lip get past the groove for the clip.

 

[Wayne County Hose]

I wish you posted a pic before. I guess I should have asked for one. I would have told you that it needs to be disassembled to be welded.
In order to slide the rod in without damaging the seals, lube it up real good, grab your rod with both hands, and wiggle it as you put it in. I like a nice circular motion as you gently push it in. This helps the piston seal work it's way past the snap ring groove. You will feel it, it's a great feeling once it slides all the way in and hits bottom. Be careful, many first timers tend to get excited and push it in too fast. You will enjoy this sooo much you may even want to share your excitement with your wife.

 

[Leejohn]

I think I'm going to rebuild all my Cyls. now, on both tractors and anything else that has a cyl. And not share the excitement with anyone.