bulgie 

Also check to see if there is a cork in the seat tube, though I think that may have only been on slightly older models. I have heard from about a dozen people who found them in their PXes though, so I'm pretty sure it was done at the factory.

If it is there, I'd remove it, lest you see this someday:


In case you can't tell from the pic, that is the seat tube, rust-perforated all the way around, i.e. the seat tube is in two pieces.
That happened because the bike was ridden in the rain. In theory, it might only take one time, but most likely it was habitual. The spray off the back tire hits the slit in the back of the seat lug, and thus enters the seat tube. Normally it would drain down to the BB shell, but the cork causes a puddle of water to stay right on top of the cork. The tiny gap that allowed the water to enter isn't big enough to allow much evaporation, especially in our cool damp climate in Seattle, so the puddle can stay there doing its dirty work, as long as it takes.

I love the irony of this happening just below the INOXYDABLE (un-rustable) decal. "How's that workin' out for ya?"

I repaired that frame, by splicing in a new piece of 28 mm (French diameter) Reynolds 531 with a backing tube inside it, that's brazed to the good unrusted metal above and below the ruined part. Probably too much work for such a common frame in such bad condition, but I hated to throw it away, and I'm a hobbyist.

This Flickr story is incomplete, doesn't show it after brazing. I may upload more pics later, but it's on hold for now while I decide what to do next. The braze came out great, but a complete paint job is too expensive, and it looks really crappy as-is. Knowing me, I'll probably hang it on a hook for 10 years, then decide what to do.

Edit: I feel a need to insist that it wasn't me who allowed this to happen! I was given the frame for free, so all I have invested in it besides my time is some brazing rod, acetylene and oxygen, and my time that I count as hobby time, no dollar value.

All my bikes have fenders except a couple that are for sunny days only, and even those get taken apart and aired out now and then, with a spritz of Frame Saver or some such for good measure. There's no way I'd allow a cork in my seat tube, and my bottom brackets have drain holes.

Mark B