Spare parts groups
Back in the days (in the 50's and 60's) when most spare parts numbers consisted of a model code and a number (possibly followed by something more), you could tell directly from the first digit in the spare part number, which section of the car, the part belonged to.
This type of spare parts numbers consists of a letter prefix denoting the model, a group number of normally 3 digits that is specific for each part of the vehicle (the first digit of which denotes the main spare parts group, the main subject of this article). This 3-digit number is also used in repair manuals and other places as a reference to a particular part of the car. Then follows yet another number of 1-3 digits for each particular spare part, and finally there might be a letter denoting versions/variants of the particular part, i.e. left/right or change in appearance/design. For example is AZ 313 01 a clutch disc for a 2CV, of the type used with a thrust bearing in graphite, whereas AY 313 01 is a clutch disc for use with a ball bearing. AZ 313 01 a is a disc with 10 splines used until April 1966, whereas AZ 313 01 c is a type with 18 splines, used after this date. If such suffix letters are used to denote the difference between left and right, the first letter in alphabetic sequence usually signifies left side.
The group prefix starts with a digit, corresponding to which main part of the car the spare part belongs to. In french, this is called the organ group (groupe d'organes). This group number is followed by a one- or two-letter code that denotes the model, the spare part was originally intended for. This model code is explained in another article here on the site.
Below, you find a summary of the spare parts groups. These have changed somewhat over time, so the precise division for each model and period must be seen in the particular spare parts catalogue. In general, however, the groups are mostly as in the table below.
|Organ group||Old classification 1948-70||Newer classification from 1972|
|1||Motor (only)||Motor, gearbox, gear change|
|2||External organs for the motor||External organs for the motor: ignition, generator, starter, carburettor, air filter, manifold|
|3||Transmission (clutch, gearbox, drive shafts)||Wheels, suspension, hydraulics, steering|
|4||Liaison to the ground (Suspension, brakes, steering)||Brakes, brake pipes, brake- and clutch pedals, drive shafts|
|5||Electrical system||Instruments and dashboard, electrical system|
|6||Security, comfort, tools||Motor suspension, fuel system, exhaust, cooling system, air conditioning, bumpers|
|7||Chassis, platform, (structural) body parts||Exterior body parts, windows, locks, dashboard|
|8||Body parts||Interior trim, tools and wheel accessories|
|9||Interior trim||General parts, not belonging to a particular group|
|10||Parts specific for electric vehicles|
When the change occurs from the old classification to the new is not a precise point in time, but the main rule is that the old group numbers kan be seen as the first digit in spare parts numbers of the type H 912 6 (where, for instance, the group number is 9), and as first digit in sheet numbers in spare parts catalogues and in numbers of operations in repair manuals. The new classification can be seen as the group numbers in prefixes to spare part numbers and as the section numbers in spare parts catalogues after around 1972.
Some examples: For a number of years in the first half of the 1990's, Citroën used this type of labels where there was a special "family" field, which sometimes contained the complete prefix (group+model) and sometimes just the group number - here "8", which shows that this is a part of the interior.
The model code is not missing because
the parts fits several models - this part only fits a Visa.
Gradually, during the 90's the prefix was transformed into the just the
group number, as here, and further to the point where it completely vanished
from the spare part labels.
Here, the spare parts group 7 is part of the prefix 7GX in front of the
proper spare part number.
Here, there is no separate group number, but we don't need it since this part
is named according to the classical scheme 1948-70, making it simple to
see that this part belongs to a HY in group 2.
If you look closely, you see a small "4" between the asterisks in front of
the spare part number. This shows that it is group 4 - hence a
brake part - but no hint as to what model we are dealing with (CX, actually).
This screw fits on an LN (as you can see from the model code RB), and since
there is a prefix (9RB) of the newer type after 1972, we have to use the
newer classification where 9 means the this screw is a general type that can
potentially belong in several places on the car.
A word of caution, though; On the newer parts, there is no group number
on the label. This reverse light switch for an AX belongs to group 5
according to the catalogue, and the number "1" on the label refers instead
to the quantity (quantité) in the package.
When this system of classification into groups started, Citroën actually
used a couple of pages in the spare parts catalogues to explain it.
This listing is taken
from the first 2CV spare parts catalogue (1953):
An example of the newer classification - here from a 1987 price list.
Mysteries for the hard core nerds 1971-74
Lastly, a small addendum for the more nerdy enthusiasts. In those years
right after 1970, where the new numbers of the type 5 000 000 emerged
and the new classification into 8 groups started as chapters in the spare parts
catalogues, these numbers were preceded with a prefix consisting of
one digit and one letter. The letter is clearly a
model designation, but the number is not
any of the known group numbers described above - neither according
to the old or the new system. The number may even be 0.
A example of this can be seen in the D-model catalogue 611 from 1972, where a
complete motor is in group 8. This, of course, makes no sense according to
the group classifications we are otherwise used to.
...and from the same catalogue, you see a bunch of clutch components belonging
to group 1, whereas the clutch control unit is in group 9
Yet another example from this catalogue, where the air intake to the fuel
injection system is in group 4, while the throttle axle is in group 1
From the Méhari catalogue 632 from 1974, where the washer pump
is in group 2 (instrad of group 5, where it usually belongs)
This type of prefix was alsp used on the labels of the spare parts.
You can see an example of this in this mirror, which is normally in
group 7 (or 5 according to the old system),
but at this point in time it belonged to the group number 2.
This practice (of "strange" group numbers), I have observed from catalogue 601 (H) from 1971, up to and including catalogue 648 (D) from June 1974. In this D-model catalogue, you can see group numbers according to both the new and old system, side by side in complete disorder. It actually looks as though the new system has been gradually phased in, already from 1972, meaning that this system of "strange" numbering only were the order of the day for a year or so!
The next catalogue in cronological sequence, I have access to, is no. 659 (2CV) from April 1975. With only a few exceptions, this catalogue solely contains the new group numbers.
I have made an attempt to list the observed groups from this period here:
|Spare parts groups 1971-74||Types of spare parts in the group|
|0||General small items (nuts, bolts etc)|
|1||Most things, smaller model-specific parts|
|2||Larger model-specific parts: motor parts, electrical parts etc|
|3||Carpets, textile roof|
|4||Air intake, exhaust and fuel system|
|5||Pipes and hoses|
|6||Seats and interior|
|7||Chassis, body, wings, doors and bonnet|
|8||Motor and gearbox complete and large parts thereof|
|9||Larger assembled units (some motor parts, dynamos, hydraulics regulators, relay box)|
This suggests a similarity with the "Rayon" system, which was used in the time leading up to this period. The "Rayon" system had been simplified into just three categories and it seemed like it was otherwise destined to disappear completely. But here, it is like the organization of the spare parts stock and handling is visible to us again - for a short while.