O-Rings and Seals

After digging here and getting some feedback on my machine, I’m beginning to realize the biggest obstacle I’m going to be tackling is O-Rings and Seals that are brittle and dry from sitting.

As I start to dig into valve body, pumps, etc. any advise? I’m just going into the pull Apart what leaks and out back together phase.

thanks

when I get hoses made, the shop puts the proper O-ring in a baggie zip-tied to the hose. IMO I don't go looking for trouble much. A little weep here or there is not worth downing the machine for who knows how long.

Get a parts blow up for what you're working on. There are so many variations. Quad rings, o-rings, O-ring face seal, o-ring boss, metric, German metric not to mention durometer rating. It's a fluster-cuck with a non-definitive sample. Better to go with the Mfrs OEM part. Less likely to invite problems.
On my truck I have a Volvo kit, a Komatsu kit, assorted generic kits and a German metric kit. And on any given day, I will find myself lacking the correct seal and get by with a "will fit" part till I can get the correct one ordered. I miss the good ol days, o-ring boss or pipe into a block and fittings were JIC.

I have a 120-3, it was leaking a bit from the swing relief valves. I noticed the right swing/left stop was kinda lazy also. I pulled the front valve and after many attempts with plumbers tape and general screwing around I eventually went an got a semi-correct o-ring fitted to it. Inspired with confidence at how brilliant I was decided to do the back valve, unscrewed it, found 2 o-rings damaged, replaced them, tried to screw the valve back and hey presto the little bollox was off thread. Spent the next 3 hours with a fine point screwdriver tracing and smoothing the threads on the valve, after many many attempts it fitted.

All is good and dry now and the lazy swing is fixed for some reason. What should have been a 5 minute job took 3.5 hours. It hasn't dampened my spirts to learn and fix the machine but ill be a little more cautious in the future, for now.

What should have been a 5 minute job took 3.5 hours.

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That is literally every single day at work. “Should” and “does” are two different things.


If you are lucky your manufacturer has standardized stuff fairly well so you can get a decent kit for what you need vs trying to “make work” generic stuff. For what I work on, a good set of ORFS, STOR (oring boss) and square seals for flange hoses does 90% of my needs and I know what size I need for the ORFS stuff by what wrench size it takes to get it apart.

I did pickup a “valve body” kit, “pump kit” and “swing motor” kit

I do have a hesitant boom up (push boom down with pressure and it goes right up)

been advised that the safety stop/safety valve is most likely stuck. It will be my first unscrew. I have been studying parts and service manual to wrap my head around how it works.

Seal Source in Portland may be your new best friend if you haven't already found them. Not much they won't have or can get/make if they can identify it for you.

lantraxco said:

Seal Source in Portland may be your new best friend if you haven't already found them. Not much they won't have or can get/make if they can identify it for you.

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Awesome! Thanks. Yeah I plan on measuring out every part as I disassemble and make sure I use the right seals/rings