Usage:
3406 ( 92U ) and 3408 ( 28V ) Engines
Description of Change: Several changes have been made to the BrakeSaver groups for the 3406 and 3408 Engines. These changes give a longer service life for the BrakeSavers.
A new rotor assembly and seal group are used. The former rotor assembly had a wear sleeve for the seal, but the new rotor assembly does not. The wear sleeve is now a part of the seal group. These changes make it possible to install the wear sleeve and seal as a unit. This will prevent damage to the seal during installation.
The plate assembly was also changed to give more clearance between it and the BrakeSaver front seal. It was some times possible for the former plate assembly to make contact with the seal. The extra clearance between the plate assembly and seal will prevent the seal damage that was the result of this contact.
The BrakeSaver groups now use larger diameter dowels to hold the parts in position. One dowel is used between the rear sleeve and housing assembly. The new dowel has a diameter of 7.92 mm (.312"). The former dowel had a diameter of 4.78 mm (.188"). A new housing assembly, stator and sleeves were also added to permit use of the larger dowel. The larger dowel will give a reduction in the wear between the dowel and its mating parts (parts that fit together).
Location of new parts in BrakeSaver group.
Adaptable As: The new parts are a direct replacement for the former parts when used as shown in the chart.
INSTALLATION OF PARTS: Install the new seal groups so the seals are at the bottom of their bore. Then make sure the wear sleeve is in the correct position, as shown in the illustration.
The new 9N6490 Sleeve can be used with both new and former parts. This is possible because two notches are machined in the sleeve, 180° apart. One of the notches has a smaller radius so it can be used with the former dowels and parts. The other notch has a larger radius for use with the new dowels and parts. Be careful to put the correct notch in alignment with its mating part.