I just replaced the O rings in an 880 and she shoots real good but if I pump it up and leave it for say 15 minutes the air is gone. How long should it hold air?

Certainly longer than 15 minutes.

Thanks Russ...that's what I was thinking.

I also have one of these. It's about 25 years old and I recently bought a seal kit and replaced them all. However, it still leaks some air. I was so frustrated that I went out and bought a new one that only lasted 4 months before the seals went bad. Its back at Daisy right now hopefully getting fixed. The manual says to use motor oil on the felt pad in the pump, but is that right? Shouldnt one use oil designed for airguns? Is the motor oil possibly hurting the seals?

Where did you find a seal kit for your 880? I've got one of about the same vintage, and I would love to get it back working again Currently, it only chronies at ~265 with 10 pumps. Also, how did you remove the c-clip honding the exhaust valve piston on the exhaust valve? That's where I gave up during the last tear down.

I orderd my seal kit from:

Jim Coplen
P.O. Box 7297
Rochester, MN 55903
Telephone: 507-281-2314

I called to confirm that he still had them and mailed him a check for $15. It arrived with a set of instructions that I had some trouble figuring out, but I eventually got all the seals replaced. The one on the pump/air piston right below the felt pad has to be compressed some to be installed and that gave me a little trouble. After playing around with it on my vise, I got it on. BTW, I removed the C clip very carefully with a small screw driver and small pair of pliers.

As an update, mine works much better now. It is holding air better and longer. It seems to be getting harder to pump and shooting stronger. I think it just takes time for the seals to seat themselves and for the oil from the felt pad to seal them. I'm still suspicious of using motor oil as the manual says to do. I would think that motor oil would eventually break the seals down. The ones I replaced were black goo when I removed them. I may eventually try some Crosman pellgun oil.

Daisy still has the new 880 that I sent them to fix. We'll see how that goes. I hope this helps and let me know how yours turns out.

Thanks for the address; I'll give him a call after the holidays. Having all of the seals in one pack will save me a lot of shopping around for o-rings at the local hardware stores.

I have used motor oil in the far back in the past for my 880, and the o-rings are still intact. I think that you would want to limit it to non-detergent oil such as chain bar oil because the additives might break down the o-rings. They're too stiff from age to hold much of a seal anymore, but I don't believe that the motor oil hurt them outright. That being said, I don't recommend it any more.

I use pellgun Oil now with good effect, but it does take some time for the oil to work it's way through. And it is a little pricey. After my last tear down, the gun started at 215 fps and climbed steadily to 265 with about 5 drops of pellgunoil on the foam wiper.

Many people have reported success using automatic transmission fluid as well, as the rumor is that pellgunoil is just ATF with some additives. I've used it but found it too hard to control how much you put on the wiper. I can say that if you put a couple of teaspoons down the gun (oops) like I did once, then the velocities will definitely decrease until the excess oil blows through :-)