FITTING 9S1812 - Caterpillar

Introduction
Many starting motors are the same, but their nose housings are in a different position. If the part numb that was ordered is different from the original part number, the position of the nose housing may need to be changed.Do not perform any procedure outlined in this publication, or order any parts until you read and understand the information contained within.Reference: Parts Book; Service ManualRemoval
Remove the electric starting motor from the engine. See the Service Manual for the correct procedure.Modification Procedure
1. Measure angle (A) between solenoid (B) (or any special location on the starter) and hole (C) on the old and new starters. If the angles are not the same, remove nose housing (1) from the new starter and move it to the same angle (A) as the old starter. 2. For starters with a solenoid, tighten 5/16-18 bolts (2) to a torque of 18 to 23 N m (13 to 17 lb ft) and M6 bolts to a torque of 12 to 14 N m (8.9 to 10.4 lb ft). Use a metal stamp to put the new part number on the plate.3. For starters without a solenoid (may have a relay), tighten bolts (3) to a torque of 10 to 14 N m (7.5 to 10 lb ft). Use a metal stamp to put the new part number on the plate.Ground Stud Relocation (If Necessary)
When replacing a 9X1490 Motor Group with a 9X1489 Motor Group, it may be necessary to change the location of the ground stud. If after rotating the nose housing, the ground stud interferes with the engine block or there is not sufficient space to install the ground cable, relocate the ground stud using the following procedure. 1. Remove ground stud (4).2. Remove pole shoe screw (5) with a T-40 Torx Driver.3. Install pole shoe screw (5) into the position previously occupied by the ground stud (4). Torque to 180 to 600 in lb.4. Install ground stud (4) into the position previously occupied by the pole shoe screw (5). Torque to 180 to 600 in lb.Analyzing Starting Motor Failure
Analyze starter failure prior to installing a replacement starter.Starter damage often results from attempting to crank with low battery (cranking) voltage on the electric starter. Engine ring gear damage may result in this situation. There are three main reasons for starter failure1. Wearout during normal starter life (2000 to 5000 hours).Wearout refers to normal or expected starter life. The starter needs replacement because:* the commutator brushes are too short.* the nose housing bearings are worn (sloppy). * or the solenoid contacts are no longer a good switch to connect the battery to the starter.The result is a starter that no longer cranks or might crank sluggishly. In this situation, the starter and starter solenoid show no real visual signs of failure. The drive gear is NOT broken or blue from heat, the armature shaft is NOT blue, there are no "hot" spots sometimes easily visible on a painted housing.2.(a) Starter stays engaged with ring