Jeep Grand Cherokee

1993-1999 of release

Repair and car operation

Sizes of fixture

For many reasons manufacturers of cars all wider and more widely apply metric fixture. However, it is important to know a difference between used sometimes standard (called also American, or the SAE standard) 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 x 1 has an inch floor in diameter, 13 rounds of a carving on one inch and length of 1 inch. Metric bolt М12 - 1.75 x 25 has diameter of 12 mm, a step of a carving of 1.75 mm (distance between the next rounds) 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 a way of survey of a head. For a start, the distance between лысками heads of a metric bolt is measured in mm, whereas at the standard - in inches (the same is fair and for nuts). As a result, the standard wrench is not necessary for use with metric fixture, and on the contrary. Besides, on heads of the most part of standard bolts usually there are the radial notches defining the maximum admissible effort of a tightening of a bolt (durability degree). The more the quantity of notches, the is higher admissible effort (on cars bolts with durability degree from 0 to 5 are usually applied). The class of durability of metric bolts is defined by a digital code. Figures of a code 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, proshtampovyvayemy on one of face surfaces of a nut while marking of metric nuts is made by means of besides figures. Than quantity of points more, or the value of a digital code is higher, the admissible effort of a tightening of a nut is higher.

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

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

Standard fixture often call also, contrary to metric, SAE standard fixture, however, it is necessary to remember that under classification of 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 on the car of bolts, nuts and hairpins it is necessary to pay attention to compliance of a class of durability of established new fixture to a class of durability of the old.

Marking of a class of durability of standard six-sided nuts

Marking of a class of durability of metric six-sided nuts

Marking of a class of durability of metric hairpins

Sizes/marking of a class of durability standard (SAE and USS) bolts

Sizes/marking of a class of durability of metric bolts

Sizes of metric carvings

Sizes of trumpet carvings

Sizes of carvings of the American standard