Spool Valve Seals

[granitepeak]

So it has always been my understanding that hydraulic spools do not have "seals", but they are just dirt wipers basically. The seal is between the housing and the spool. They are honed to match at the manufacture and the seal is steel to steel. I think you are wasting your time replacing them, it will probably still leak.

It will not hold back operating pressure for sure.

 

[granitepeak]

If you can successfully remove the seal without taking out the spool, then you will have to slide it over the exposed upper part of the spool. That will require that the upper part of the spool is very clean and free of paint, rust, and other bad stuff.

Very true.

 

[the old grind]

Looking again at the diagram, #14 seems to be more a seal on both ends of the sleeve itself, the top one being perhaps changeable by just pulling the sleeve partway out. (O-ring?)

My advice on page one was with expecting #18 to be a lip seal with steel shell/face vs say a poly bushing/wiper, I now agree more likely. If that wore enough to let dirt gum up or mess #14 changing both would seem to vet whether the bores were worn enough that a good #14 wasn't enough to reduce the leak enough.

If what leaked between #14 & #18 could drain to return, would the top one have to contain much pressure? (unlikely :laughing Double-lip seals at both ends of crank/cam shafts contain oil pressure that I bet is fairly higher than return pressure in an OC valve/stack.

 

[granitepeak]

I looked up #14. They call it a ring seal, so your correct. I think I will pull 1spool and prepare myself for a new valve assembly and the work required to make it work.
Thanks
Don