Just picked this up yesterday and trying to find out more info about it. Figured it would be easier to share a link full of photos vs uploading them all here. Please let m know what you think.

https://www.icloud.com/sharedalbum/#B0MG4TcsmG5SmwZ

UO-8/UE-18 around 1973-74 would be my guess.....Looks in nice condition.

Very nice; lots of original parts on this. Looks like a UO-8 to me as well.

Awesome. Now time to clean it up.

Those derailleurs are famous (or infamous) for not holding up all that well. They worked well when new but the delrin, plastic derailleurs just did not hold up well. I'd be tempted to take them off and find something used. If there's a bike coop nearby, that's a good place to find some decent used derailleurs.

rear shifting is actually the thing that doesn't work on the bike. No doubt already past end of life.

Nice and clean.

My daughter's college bike is also a UO-8, with the original Simplex Prestige plastic derailleurs. They work fine, until they crack, which might be tomorrow or never. So keep them lubed (the plunger that slides in and out of the front derailleur especially), periodically apply some Armor All or other plastic-vinyl protector, don't over-tighten the front derailleur's mounting screws, and worry about replacing them when they actually need replacing.

The rear derailleurs held up better than the fronts. Your bike looks barely used - freewheel teeth show little wear - and I'd clean up the rear derailleur then start troubleshooting. It probably just needs an adjustment, unless you see an actual break or crack in the plastic.

So, from what I am reading I really need to change out the stem or else I am going to die from failure.

The odds of an Ava "death stem" snapping are probably overstated. But on the other hand, if it does break, you're going to suddenly lose control of the bike and you're probably going to crash. Personally, even though I thought the risk was pretty small, I replaced the stem on my own Peugeot UO-8. But I also did it to accommodate a wider handlebar since the stock bar was uncomfortably narrow.

I can see from your pics that your front derailleur's cracked. No surprise there! SunTour made a couple of derailleurs that use similar cable routing. A SunTour Spirt or Compe-V can typically be found for $10 or so on eBay, often still in its original packaging, and would be a plug-and-play replacement. A rear SunTour derailleur from the same period also makes an excellent replacement for the Simplex rear, if necessary. Just because your rear isn't shifting right doesn't mean your derailleur's broken, so you may want to troubleshoot before replacing it. (On the other hand, a decent replacement is bound to be more reliable, so it's your call.)

If you're curious to pin down the date of your bike as closely as possible, you'll probably find date codes on a few components. On the backside of the rear derailleur's cage, right between the two pulleys, you'll probably find a stamp with the month and year the derailleur was made. You may also find date stamps on the rims and hubs.

Well the good news is the stem came off freely and I was able to remove the seat post. However, there appears to be a spacer inside the seatpost. is this ok to remove if I plan on changing out the seatpost. I suspect it is. I haven't actually removed anything, just made sure I could remove stuff if I wanted and when I am ready.

It's a UE8, as opposed to a UO8. You can see the generator mounting tab on the non-drive side seat stay. it's missing the head light, generator, wiring harness, toll kit and pump. Outside of the saddle and bar tape, it appears to be OEM. It still has the mini-hoods, brake lever grips and rear light lens, which is quite rare to see.

UO-8's and similar Peugeots used an odd-sized skinny seatpost with a shim, as you've discovered. It would be OK to remove the shim and use a bigger seatpost -- you wouldn't be the first to do so -- but you might want to have the seat tube reamed since the tube may not have been reamed at the factory. And there seems to be some disagreement about what size post these frames would take, so it may be a good idea to have it reamed and measured at a local shop.

Sheldon says 25.4.
Forumite twsindypa used a 25.6.
A few other forum regulars measured theirs to be 26.0, but a tight fit.
...and I'm not pulling my own UO-8's seatpost and shim to measure. ;-)

Well I can and should just leave it be. It's not like anyone is going to see the seat post anyway so who cares. And this bike is just at the max size for me when I straddle it, so I don't think I am going to have much exposed anyway. I think this would end up being something I would spend time and money on that just wouldn't make a difference. But can I get normal seats to fit on that tiny post I guess is the question.

Yep, the old school clamp on that post will fit a standard saddle just fine. The down side to the original post & clamp, other than a little bit of extra weight, is that the notches in the clamp don't allow very fine saddle angle adjustment. If you find that you can't get your saddle angle just right, try flipping the clamp over since the notches may not sit at the exact same angles with the clamp upside-down.

The "broken" rear derailleur ending up being the butterfly nut wasn't tightened at the shifter. I was able to shift both front and rear without any issue. I took off the rear derailleur and cleaned it up. uploaded additional photos.

Wow those wheels are crazy heavy. I think the back one is 10 lbs. Also removed the luggage rack and fenders.

So since there is a "72" stamped on the back of the derailleur, can I assume that is the year? So then this now tells me the bike is a 1972 Peugeot UE 8.

So that means at least the RD is from 1972! I think you are safe assuming a 72 UE-8 since figuring out Peugeot build dates is more art than science anyway. And FYI UE series only differed from the UO series by the brazeons for the rack and generator, so yours is the equivalent now of a UO-8.

Looked like the stem was a ATAX so the stem should be fine.