Questions about poppet valves?

I recently purchased 4 used cornies, 2 from one homebrewer and 2 more from another. I proceeded to take apart one of them and found that most of the O-rings were in pretty bad shape and so I decided to replace them all. My questions are regarding the poppet valves:

1) Is it worthwhile to replace the poppet valves given that the other O-rings were not in very good shape?

2) If I remove the poppet valves and find that the O-ring on them is in reasonably good shape, can I pop them back in or does removing them damage them too much? Is there a good way to remove the poppet valves without damaging them? As near as I can tell, the only way to remove them is to push on them until they give, which risks damaging the little legs which hold it in place.

3) One of the guys I bought from gave me some spare parts with the kegs. These included a couple of extra poppet valves and a couple of extra ball lock assemblies. Unfortunately, the poppet valves won't "pop" into place as the little legs on them seem to be damaged/snapped off. However, I noticed that if I put these damaged poppet valves in place and screw the ball lock assembly onto the keg, the poppet is held in place and seems to work fine. Is it OK to use the poppet valves in this manner or do you need them to be snapped in place in the ball lock assembly?

Thanks for any and all replies.

Cheers,

Greg

Those damn poppets will drive you crazy. I am in a similar boat and have had to replace several, I have a couple of stems that I simply cant find suitable replacements for after buying one of every one I could find online.
I have several that only stay in place when they are screwed on.
The only test you need to pass is "Does it hold pressure?" If it does, don't muck with it.

I've reconditioned a lot of kegs and almost every one had the poppits easily come out just by pressing a screwdriver on the poppit from the top and giving it a sharp rap (most of them actually just fall out).

The poppit does not need to "snap" into place, most of them done that I've seen. The spring gets compressed by the little feet sitting on the dip tube top.

Also in the 50 or so kegs I've done I've not replaced any poppits, overnight soaks in star-san, new Orings and they are good to go, holding pressure.

As already said above, the poppets do fall out or are easily pushed out. I'd add that you get yourself some Keg lube, (Food grade o-ring lubricant) I got some on the Dow Corning web site. Look for Compound 111, you can request a free sample. I got mine last week. It is a 150g tube. That is enough to last about 10 home brewers their whole lifetimes.

A very little bit goes a very long way

dp