We are repeatedly queried about the significance of the PR numbers used in our catalogue for VW, Audi, Seat and Skoda vehicles. A note in the manufacturer’s documents gives this explanation:

"For process control reasons and in order to ensure unmistakable identification of the brake system in a vehicle, it is necessary to write up brake parts with PR numbers. These are to be found on the service data medium in the trunk and in the service booklet."

This means: identifying brake parts is no longer possible solely by taking the vehicle, its production period and/or the chassis number. The PR numbers permit the only exact determination.
These numbers always have THREE CHARACTERS; they read, for example, "1LB" or "1KD".
PR numbers have being seeing use at VW since 1999.

In our paper catalogue K14 it looks like this:

The "service data medium", that is, the sticker in the trunk and/or the service booklet, might look like this: (The two arrows mark the PR numbers used in this case for the brake system).

Incidentally, all other PR numbers likewise serve to identify the brake parts used, but do not refer to the brake system.