Doing a reseal on a large 115mm rod x 175 mm bore cylinder. The piston was stuck on the rod. There was foreign metal in the threads between the piston and rod not allowing it to unscrew. Had to cut off the brass cushion and get in there with a grinder to cut out the metal. Had to machine a new cushion and clean up the threads but nothing serious.
Notice the brass cushion to the right of the pistion. Pic is after we got it back together.
Put it back in the machine and within minutes noticed loss of power and fluid bypass.Took it back apart to find the inner back up ring inside the piston had blown out, pushing the o-ring out. That's when I noticed all of this cracking. Called the shop that did it and they said it was some kind of product they put on the piston to fix the damage caused from cutting off the metal inside the threads (like a 2 part epoxy for hydraulics?). The area they put this stuff on is where the cushion sits against. They think the o-ring was damaged when putting it together.
They told me to just clean that stuff off that's cracking and leave it as is because there's enough lip that's not damaged that can hold the o-ring and backup in place without issue, replace the backup ring and use Loctite 515 on the threads to help keep any fluid from pushing threw the threads and possibly blowing out the oring again.
I just do reseals as a side job so I might not know much, but I didn’t know there was any kind of 2 part epoxy or liquid “weld” that's safe inside a hydraulic system? Also I don’t believe Loctite 515 is safe inside the hydraulic system? And I’m also concerned that this area that is damaged where the cushion sits will shave metal off over time from the brass cushion sitting against the damaged area.
I'm looking for a second opinion on what I should do and if what they're telling me is correct. I’ve dealt with this shop for years and they’ve always done me good but I'm questioning this.
Notice the brass cushion to the right of the pistion. Pic is after we got it back together.Put it back in the machine and within minutes noticed loss of power and fluid bypass.Took it back apart to find the inner back up ring inside the piston had blown out, pushing the o-ring out. That's when I noticed all of this cracking. Called the shop that did it and they said it was some kind of product they put on the piston to fix the damage caused from cutting off the metal inside the threads (like a 2 part epoxy for hydraulics?). The area they put this stuff on is where the cushion sits against. They think the o-ring was damaged when putting it together.
They told me to just clean that stuff off that's cracking and leave it as is because there's enough lip that's not damaged that can hold the o-ring and backup in place without issue, replace the backup ring and use Loctite 515 on the threads to help keep any fluid from pushing threw the threads and possibly blowing out the oring again.
I just do reseals as a side job so I might not know much, but I didn’t know there was any kind of 2 part epoxy or liquid “weld” that's safe inside a hydraulic system? Also I don’t believe Loctite 515 is safe inside the hydraulic system? And I’m also concerned that this area that is damaged where the cushion sits will shave metal off over time from the brass cushion sitting against the damaged area.
I'm looking for a second opinion on what I should do and if what they're telling me is correct. I’ve dealt with this shop for years and they’ve always done me good but I'm questioning this.
