Walther LP2 velocity variation

[jgb133]

I've had this gun for a few weeks, I shot 150 rounds through it initially and it seemed fairly consistent. Yesterday I went out and now it seems there's hardly any pressure in it it all and the velocity varies from shot to shot. John Gronewald (JGAirguns) rebuilt this back in February. I don't know how much action it's seen since then. I do know he replaced just about everything that was rubber. Is there anything I need to know? I do see the oil hole in the side of the grip. Does anyone know what sort of oil I should use, what quantity, and what frequency I should oil this gun? Any assistance or advice would be appreciated.
Regards,
Jim Beier

[RobinC]

Jim
It does have the ring of failed seals, although it could be the valve itself as the springs do go weak and the valve can have wear. If rebuilt with the correct factory parts they should last near enough a lifetime, usualy they rot with old age rather than wear, when we used these guns in the days when they were state of the art they rarely failed.
I've heard that some of the so called web "experts" use cheapo non standard parts, and revel in making their own modifications, but the original is best, and most parts are still available. The only lube should be done at build and last the life of the system, oiling will cause more problems. It may be dirt in the valve if its been oiled, take it apart and see, if you can see no deteriation or damage, clean it and rebuild it dry, it may sort it. I've done a couple of LGR's which is a similar sytem and the easiest way to fix them is to replace the valve as a unit ( about £25). Speak to Bill, at the contact I gave earlier.
Best of Luck
Robin

[jgb133]

Robin,
When I cock the lever down, the air gets sucked in. When I cock it back up I hear air escaping out of the barrel. I noticed that if I cock it 2-3 times, the pressure increases. Is this indicative of the valve failure you spoke of? It seems from the illustrations I've seen, that replacing that o-ring doesn't seem so bad. I've seen many websites where they have an assembly diagram for an LP3, but only a partial for an LP2. Would you know if one exists and if so, where I might get a copy? It never fails that when you have something planned, things break.
Regards,
Jim Beier

[jgb133]

Everyone,
Robin and others suggested it could be the exhaust valve seals. I was thinking to myself, that can't be, these were changed 9 months ago. This gun has been sitting in my fathers basement for 35 years because the seals died on him in the early 70's. We live in the middle of nowhere in Illinois, and you couldn't find anyone back then to work on these, so it just sat. He asked me to find someone in January this year and I did. We informed the repair shop that this gun hasn't been shot in 40 years and to go over it well. I assumed that is exactly what happened.
Imagine my surprise when I take the valve asembly apart and see a flat seal that is imbedded into the metal and all the other parts covered with 45 vyears worth of film. It appears that this wasn't even touched! So, here's my question "Wouldn't you have looked at this and cleaned it knowing it's sat for so long and these parts are subject to failure?" I'm ordering a new flat seal, spring and o-ring. I hope this fixes this for a while.

Thanks Robin for your advice!

[RobinC]

Jim
The problem is there are so many self styled experts about, these things are not rocket science so that just indicates the level of engineering expertise of some of these people.
Al that is needed is good engineering practice, common sense, and attention to detail. There are breakdown drawings on the Carl Walther website, look in downloads. If you have any dificulty getting parts contact Bill, he is Walther factory trained, and has a wealth of experience. I would recomend changing the complete valve as a unit.
I presumed you were in Florence, Italy? Are you in the USA?
Best regards
Robin

[jgb133]

Robin,
I'm in Florence, South Carolina. I did contact Bill and I gave him the laundry list, which includes everything you recommended. I'm awaiting his reply. I'll report back when I get the parts and having fixed the gun.
Best Regards,
Jim Beier