Sherwood Oasis second is supposed to trail bubbles?

[Fishpie]

No real science.
Just don't want to push what's clogging the filter further down the pores.
Yes, try Dawn....and vinegar too.
I haven't tried an ultrasonic but would probably go the least aggressive route and work up if that was unsuccessful......again not hypothesis tested.

 

[tbone1004]

I'd try dawn and white vinegar in a heated ultrasonic with the filter vertical and give it a few cycles, that should clear it up quite a bit....

 

[tech_diver]

I have been watching this thread with a lot of interest and nostalgia. Years ago, I worked for Sherwood for quite a while and have seen the dry bleed system destroyed in ways I would've never imagined. I've seen them sealed with silicone glue, I've seen screws with o-rings driven into the bleed port. As others have pointed out in this thread, the older model pistons with the sintered element were very susceptible to clogging. Even the oils from the the technicians fingertips could affect the flow rate. If the flow rate was out of spec, the first stage would not balance properly against ambient pressure.
I had heard stories of the old filters being brought back from the dead but only in legend. The process that Fishpie outlines sounds very intriguing. I know people who have tried to bring them back to life in the ultrasonic cleaner but the contaminants that float on the surface of the cleaning solution can recoat the part as you take it out of the bath.

It would be interesting to hear more stories of zombie pistons brought back to life.

 

[ams511]

I know people who have tried to bring them back to life in the ultrasonic cleaner but the contaminants that float on the surface of the cleaning solution can recoat the part as you take it out of the bath.

In the Vance Harlow book he recommends laying a paper towel over the surface of the solution to trap the oil. May not get 100% but it would sure be better. I would try boiling and steaming first before starting the ultrasound. I would assume you would need more than one pass to try to clean it.