Jeep Grand Cherokee

1993-1999 of release

Repair and car operation

The sizes of fixture

For many reasons manufacturers of cars all apply metric fixture more widely and more widely. However, it is important to know a difference between used sometimes standard (named also American, or standard SAE) and more universal in system of measures metric fixture as, despite external similarity, they are not interchangeable.

All bolts, both standard, and metric are classified on diameter, a step of a carving and length. For example, the standard bolt 1/2 - 13 х 1 has an inch floor in diameter, 13 coils of a carving on one inch and length of 1 inch. Metric bolt М12 - 1.75 х 25 has diameter of 12 mm, a step of a carving of 1.75 mm (distance between the next coils) and length of 25 mm. Both bolts are outwardly almost identical, however are not interchangeable.

In addition to the listed signs both metric, and standard bolts can be identified by head survey. To begin with, the distance between лысками heads of a metric bolt is measured in mm, whereas at standard - in inches (the same is fair and for nuts). As consequence, the standard wrench is not necessary for use with metric fixture, and on the contrary. Besides, on heads большей parts of standard bolts usually are available the radial notches defining the maximum admissible effort of a tightening of a bolt (durability degree). The more quantity of notches, the above admissible effort (on cars bolts with degree of durability from 0 to 5 are usually applied). The class of durability of metric bolts is defined by a digital code. Code figures are usually cast, as well as for standard, on a bolt head (on cars bolts of classes of durability 8.8, 9.8, and 10.9 are usually applied).

Also on labels of a class of durability standard nuts can be distinguished from the metric. Dot labels are applied to identification of durability of standard nuts, проштамповываемые on one of face surfaces of a nut while marks of metric nuts are made with the help besides figures. Than quantity of points, or the above value of a digital code, the above admissible effort of a tightening of a nut more.

End faces of metric hairpins also are marked according to a class of their durability. Large hairpins are marked by a digital code whereas marks are put on smaller in the form of a geometrical figure.

It is necessary to notice that the considerable part of fixture, in particular a class of durability from 0 to 2, is not marked at all. In this case unique way of difference of standard fixture from metric is measurement of a step of a carving, or сравнивание carvings with unequivocally identified.

Standard fixture often name also, contrary to metric, fixture of standard SAE, however, it is necessary to remember that under classification SAE only small fixture gets. The large fixture with not metric carving is fixture of the American standard (USS).

As the fixture of the same geometrical size (both standard, and metric) can have various classes of durability, at replacement by the car of bolts, nuts and hairpins it is necessary to pay attention to conformity of a class of durability of established new fixture to a class of durability of the old.

Marks of a class of durability standard шестигранных nuts

Marks of a class of durability metric шестигранных nuts

Marks of a class of durability of metric hairpins

The sizes/marks of a class of durability standard (SAE and USS) bolts

The sizes/marks of a class of durability of metric bolts

The sizes of metric carvings

The sizes of trumpet carvings

The sizes of carvings of the American standard