Saab SONETT III Service Manual page 24

GENERAL HINTS
General
All shop personnel will be aware of the importance of
tidiness and good order in the shop; similarly, every expe-
rienced nnechanic realizes that certain parts of a car must
be treated with care and protected from din and foreign
matter while being serviced. For the new man, who may
not be so familiar with the kind of work involved, the
following hints may be of help:
1. Protect fenders and other painted areas with suitable
covers while working with the car. It is easy to get
grease stains or scratches on the paintwork, but it is
far more difficult to remove them.
2. Protect the upholstery from oil, etc., by using protec-
tive covers.
3. Clean the car thoroughly under fenders and around
the rear axle before starting work on hubs and axles.
Apart from making work easier, this prevents dirt and
grit from getting into bearings and other susceptible
parts.
4. Before removing a spark plug, carefully clean the
recess around its head.
5. One of the basic prerequisites of good service is the
choice of a suitable place for each job. It would be
most unsuitable, for instance, to dismantle an engine
or a gearbox on or near a bench used for filing or
similar abrasive operations.
Thread system and wrench sizes
The thread system mainly used in the Saab car is the UNC,
i.e. UN IF I ED COARSE TH R EADS, in which inches are
the unit of measurement.
Wrench sizes for nuts and bolts are expressed in inches
and the dimensions are the same as the designations of
the tools. In a few cases, UNF, i.e. UNI Fl ED FINE,
threads are used.
An important exception is the engine, which has metric
thread system.
Exceptions to the thread system will also be encountered
in the case of components supplied by sub-suppliers, such
as Bosch, where metric threads will be found.
Nov. 1972
SAAB
100-1