I don't think the rear brake has an adjusting barrel, but I'll have to dig through the parts I took off my wife's bike. The Peugeot has a french threaded bottom bracket so you;ll probably need a square taper BB that's french. Depending on the year, the Motobecane is probably Swiss. Do a forum search, there's a lot of discussion on this topic. I re-built a UO-18 for my wife...replaced the brakes, crankset, wheels, saddle, shifters, and RD.