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FAS604 Repair
Posted: Sun Nov 05, 2023 7:51 pm
by fc60
Greetings,
I have disassembled my FAS604 into the basic components.
Now I am stuck.
How do I remove the plunger in the photo to replace the O-Rings?
Cheers,
Dave
Re: FAS604 Repair
Posted: Mon Nov 06, 2023 12:22 am
by marky-d
Pull hard.
Mine was stuck pretty badly -- the o-ring had turned to paste. I don't remember what I finally used to get it out; I think I may have used a piece of wood or brass to wedge under the 'button', then levered it against the body.
marky-d
Re: FAS604 Repair
Posted: Mon Nov 06, 2023 1:56 pm
by fc60
Greetings marky-d,
Many thanks!!!
I shall go and exert more force.
Cheers,
Dave
Re: FAS604 Repair
Posted: Mon Nov 06, 2023 9:07 pm
by fc60
Greetings,
I am at the O-Ring point.
Looking at Buna-N (70A) material as it is oil resistant. (I ordered a tube of Crosman PellGun Oil.)
Interesting as the O-Rings I removed (Piston and valve) were Red suggesting they were Silicon.
When I put the beastie back together, what FPS via the chronograph should I get with 7 grain pellets to assure myself I did a good job of assembly?
Cheers,
Dave
Re: FAS604 Repair
Posted: Tue Nov 07, 2023 8:04 am
by Rover
Not too long ago, there was a thread on rebuild for max velocity. Go hunting!
One thing I did notice was that you could get a velocity increase of around 20 fps by using RWS Meisterkugeln Blue (pistol) pellets.
Re: FAS604 Repair
Posted: Tue Nov 07, 2023 9:13 am
by Gwhite
fc60 wrote: ↑Mon Nov 06, 2023 9:07 pm
<snip>
Interesting as the O-Rings I removed (Piston and valve) were Red suggesting they were Silicon.
<snip>
Unfortunately, O-ring colors aren't standardized, and are often meaningless.
https://www.globaloring.com/oring-colors/
"
It is never safe to assume an o-ring is a specific material based on the color alone." They are also happy to make custom O-rings in any color you want...
I think the colors used in the US are also different from what the Europeans use. Walther used to use green polyurethane O-rings in their CO2 pistols, but I think the green O-rings Steyr uses now may be Viton.
Nitrile should be fine, but you may find that a harder (like D90) O-ring holds up better in some applications than the standard D70. The FAS isn't a high pressure application, and the D70 is probably fine.
Re: FAS604 Repair
Posted: Thu Nov 09, 2023 4:48 pm
by brent375hh
Rover wrote: ↑Tue Nov 07, 2023 8:04 am
Not too long ago, there was a thread on rebuild for max velocity. Go hunting!
One thing I did notice was that you could get a velocity increase of around 20 fps by using RWS Meisterkugeln Blue (pistol) pellets.
Where can one purchase these blue pellets?