Wednesday, January 18, 2017

FWB 124 Replacement Piston Seal Quickie.

My friend Guy, who traded his FWB 124 to me years ago, managed to convince me to trade it back to him a while back. Recently he found it had no power and wasn’t pushing the pellet out of the barrel. We’ve covered FWB 124 disassembly already on the blog, but I thought the pictures of the damage and the replacement Maccari piston seal and spring warranted a quick post.
At first I thought Guy had gotten sand in the gun, but it turned out that the piston seal had completely crumbled, so that even before I got the piston out little chunks were coming out with the spring.
That’s a decomposed seal…glad it stopped shooting before it completely disintegrated.
Had to chew up the old seal to get it out, compare it to the new Maccari seal.
The new spring with spacers, compared to the old bent one. Good to replace it anyway. I didn’t do anything special, the piston seal was a little snug, but not tight so I didn’t machine or sand it. Lubed everything and put it back together. Fired 4 shots before it started to rain (Oregon winter), first one dieseled, but the last three were all 846 fps, which is amazingly steady. I’m sure it will continue to change over time as it all wears in.