Peugeot Tandems
Maintaining and Updating The Peugeot Tandem

Rim brakes
The Peugeot Tandem is equipped as standard with 3 brakes. This is very common on tandems, to cope with the additional weight. The rim brakes are special Mafac Tandem cantilevers mounted on brazed-on bosses on the forks and seat stays.

The third brake is a drum brake fitted to the rear wheel and is intended as a "drag brake" for scrubbing off excessive speed and controlling long descents before bringing the machine to a halt with the rim brakes. The arrangements for controlling the brakes is unusual, though not unique. The drum brake is controlled by the left hand lever and both rim brakes are controlled by a special design of lever with a dual cable entry. This arrangement works well in my experience, but some teams have adopted the more common arrangement to control the hub brake of a lever on the stoker's handlebars or a ratchet gear shift lever on the captain's.

The drum brake is covered in the Rear Hub/Brake blog of this website. this blog covers the rim brake arrangements.

Rim Brake Details
The spacing of the bosses for the cantilever brakes is wider than those on modern bikes, so the standard cantis can not easily be upgraded to "direct pull" brakes otherwise known as " V brakes", which are made for a post spacing of 80mm. Neither are new cantis available for this post spacing (62mm). The best option is stick with the existing brakes, which are more than adequate.
Note some later Peugeot tandems have "standard" cantilever brakes rater than tandem ones. These are less effective.