Hydraulic leak on port weld

[botaplayer]

So I have developed a pin hole leak on a SMC loader model 64QS on one of the bucket cylinders. It is dripping about every 5-6 seconds . See circle in picture, I wiped it off and took a picture just as a drop was forming, it is the weld around the port. Can I drain the cylinder and spot weld this? what is the suggested fix. Thanks

 

[metalbender]

With the piston at the cold end, tig weld would be the preferred method. All about control.

 

[Billrog]

I've done a few, piston at opposite end good and clean no oil grind it out good and deep then weld it up.

 

[botaplayer]

I was originally thinking about just replacing so I guess I really have nothing to lose by trying to fix it. It has lasted for 27 years with original equipment. Thanks everyone!

 

[dfkrug]

I have had these pinholes numerous times. If you don't grind it out well, AND burn the oil out with heat first, you will get more pinholes.

I use MIG, but brazing works well, too. TIG, if you have it.

 

[muddstopper]

I think I would try the sharp punch trick before welding. I have stopped quite a few leaks with just a punch and hammer. Take your sharp punch and place it right in the middle of the pinhole and give it a good hit with the hammer. Then make a series of otherstrikes around the outside edges of the centerpunch mark. This squishes the metal around the pinhole and closes up the hole. This method wont work on a crack, altho using on a crack might buy you a little time until you can fix proper.

 

[dfkrug]

I have stopped quite a few leaks with just a punch and hammer.

I have never tried that, but it is worth trying. I will try that next time since you do not need to take the cylinder out of service to try it. Good idea.

Sometimes the pinholes are microscopic. I have had some (rare) that pass the air test (120psi with soap), but fail in service (2500psi). I always air test first, since it does not contaminate the pinhole with oil.

 

[Tractor Seabee]

I have never tried that, but it is worth trying. I will try that next time since you do not need to take the cylinder out of service to try it. Good idea.

Sometimes the pinholes are microscopic. I have had some (rare) that pass the air test (120psi with soap), but fail in service (2500psi). I always air test first, since it does not contaminate the pinhole with oil.

Back in my industrial refrigeration days always carried a ball peen hammer and center punch. Shut downs for weld repair have to be scheduled around plan ops. Prick punching as described makes a good temp fix. Even have went back several years later said; "hey did you ever have that pinhole fixed?". Often come back was; we forgot and it does't leak so why fix it now?" These are ammonia lines so a leak becomes evident in a hurry.

Ethics of this: never do that to a customer's plant w/o them knowing what you are doing.

Ron