TargetTalk

My LP10 was leaking badly after screwing on cylinder.

After examine the cylinder, all contact O-rings, the problem came down to leaky pressure decreasing valve. Opened it up, noticed the 0-ring distal to the washers were threaded. They were 10-15 finely perfectly formed o-rings, each thickness of hair strand.

They must be shaved off from the original O ring.

What caused that?

What to replace it with? Nitrile or harder Viton o ring. On the LP10 diagram, that is a very odd size o-ring 8.92 X 1.82 (part 29.8)

http://www.pilkguns.com/wp-content/uplo ... 10_man.pdf

Those 10-15 shaved off Orings caused by abrasion against guiding sleeve (part 29.6)?

Its a British Standard O ring,
O-ring BS904 8.92mm ID x 1.83mm CS FKM 75
I have found Nitro 70 or 90 both work well.
Dont forget to lube the Oring on install.

The AS568 -904 part number meets those o-ring dimensions. McMaster Carr sells 100 of these Buna-N o-rings for $3.35: https://www.mcmaster.com/#9751k114/=1axwvhc. Dow Molykote 33 is a good o-ring lubricant, along with SuperLube grease.

The pressure decreasing valve is still leaking air. Not at the end where cylinder screw on, but from the other end of regulator.

Changed #13 O-ring 18x2 on the other side of regulator. Also changed O-rings inside, "close" but not the exact sizes.

Just wondering, if it is leaking at the 18x2 O-ring side of the regulator, leak must be coming from that O-ring, right? Leak could not have come from O-rings INSIDE the regulator if 18x2 O-ring at outside back of regulator is sealed functionally, right?

Fixed leaky pressure decreasing valve for LP10

Lesson for people with similar problem later

Leak at distal end, not from the side that cylinder screws on, can come from two O rings. One on the inside and one on the outside.

Once inside O ring is placed, the whole assembly MUST be properly pushed into the hole enclosure. Push it in, make sure it is push and seated tight in the hole retainer.

If it is somewhat loose and o ring is slightly outside of hole retainer, the guiding sleeve with repeated firing of pistol, will shear/cookie-cut the outer edge of o ring to pieces.