Vacuum evacuating and filling shockabsorber with oil

My homebuilt tools for vacuum evacuating the trapped air and filling shockabsorber with oil.
Real shock parts in plexiglass housing. Must replace o-rings that leak.

[@MrAirbleed]

However old this video, this is so helping me sir. Thank you very much

[@HP_rep_mek]

The idea is that I will get back to this and redo the piston and seals so they are not letting air pass by, but with many other projects it’s still on the waitinglist😇

[@crice1uk]

Correct me if I'm wrong but you're pulling the vacuum/oil from a place on the shock which wouldn't usually have a port? Also why does the floating piston move to the opposite end of the piggyback reservoir if you're pulling a vacuum, that one really confused me??

[@HP_rep_mek]

Most shocks have a bleedport, or a port for a rebound adjuster (I have adepters for those).
This is a shock absorber manufactured from acrylic tube by me to see how long it takes for the airbubbles to disappear).
If you draw vacuum, the low pressure sucks the piston (or anything thats moving freely, aka the shaft is drawn into by vacuum also as you can see).

[@mx1209]

Awesome. Good work on the acrylic shock, amazing.

[@RiddleKingOnline]

Please correct me if I'm wrong about this video. Is what's happening here the cycle of vacuuming an oil reservoir (the metal tank on top) which is attached to the shock to pull all the air out of the system where it rises to the top of the reservoir and then pumping pressure into that same reservoir forcing oil back down into the shock and is this achieved by the air in the reservoir rising to the top and the oil being pumped in via an outlet at the bottom of the reservoir to avoid pushing air back down the tube? If so, it almost all makes sense, BUT, why then is the entire process done under pressure? Starting to think I've gone wrong somewhere. Please help I really want to tune my shocks properly and really really want to understand them.

[@RallyRat]

Pulling a strong vacuum causes air bubbles to expand greatly. By reducing the pressure to 5% of atmospheric, for example, air bubbles will expand to 20 times their original volume causing them to rise very easily. Much of the air will come out through the tube connected to the bottom of the oil tank, when air is allowed back into the top of the oil tank, the expanded bubbles left in the shock will collapse and draw oil in. After a few cycles almost all of the air will be pulled out; any air volume that is left will be further reduced by a factor of 5 to 20, depending on the final gas charge pressure.
The shock is shown placed inside a vacuum chamber, this may be to prevent seals (all of which are designed to contain internal pressure, not external pressure) from letting air in during the bleeding process.

[@nvmcrider8475]

Great job on your video! Have you or could you do another one explaining your setup in more detail?

[@HP_rep_mek]

NVMCRIDER it’s a really old video😋
I think I have some videos somewhere, you might try to look in my older Instagram posts:
instagram.com/hp.rep.mek/
It’s a vacuum pump with a tank for shock oil, and one hose only to the shock:s bleedport.
This was a homemade shock made out of lathe turned acrylic, all kinds of leaks. I have it and an Öhlins shock with body of perfect sized acrylic instead.
Someday I will get to that and make some better video describing how the trapped air is flowing out of a shock when filling it with oil!

[@nealblath]

WTF