Rebuilding Koolance QD3s:

[AnonymousGuy]

 

So I'm going after "fixing" QD3's sticking open on the female component.  If you ask Koolance they're not meant to be disassembled, but in reality it's not that hard to do although it's not something an average PC DIY person is going to be able to do.  The threads that hold the body together are sealed with a clear sealant so you need a 12" wrench to break it open and it will leave jaw marks.

 

So new o-rings everywhere (in a male female set there is 4 o-rings not including the G1/4 ones), fresh silicone grease on them, and a stronger spring to push the "piston" up more better.  The piston is top right in the photo, it slides in the barrel to the left of them around the stem in the center of the photo.  The bottom and left of the photo are the male components.  Top left is the release-ring for the female side.

 

My guess why the female end sometimes sticks is the o-ring lube gets washed out eventually and random shit sticks to it, causing it to freeze in the barrel.  The spring is only about 5lbs of force which isn't enough to overcome this.  I suspect they put more aggressive springs on the newer generations and maybe improved the sealing profile with chrome instead of nickel plating the brass.

 

Assembled: