Detroit Diesel — Alternator Reassembly
Repair & overhaul
From a Detroit Diesel service manual — check it applies to your exact model before use.
Before you start
- Hazardous voltage. Operate the generator set only when all guards and electrical enclosures are in place.
- Tightening the hardware. Flying projectiles can cause severe injury or death.
Procedure
- Attach exciter field to end bracket with four mounting bolts; torque to specifications.
- Place stator vertically with end bracket side up; position end bracket housing eye opposite stator mounting bracket.
- Place end bracket on stator, align with bolts, and tap flush with rubber mallet.
- Attach end bracket to stator with original hardware; torque to specifications.
- Suspend stator; lower to within 12.7--6.4 mm (1/2--1/4 in.) of adapter lip.
- Align adapter and stator; start bolts with washers, lower stator and tighten; torque to specifications.
- Lower alternator assembly horizontally; support and maintain 25 mm (1 in.) clearance.
- Install rotor shaft bearing using hydraulic press, bearing heater, or mallet and steel stock.
- Hoist rotor vertically; lower into stator, aligning bearing into end bracket.
- Place fan over rotor flange; torque bolts to specifications.
- Align drive disks with hex holes together and burr sides facing same direction; use alignment pins.
- Attach drive disc(s) with hex hole at stator bottom position or within 60 degrees CW/CCW; torque to specifications.
- UA alternator only: fill with Chevron SRI2 grease until visible at vent/sight hole; replace screw and torque.
- Install flywheel studs using Loctite No. 271 red; apply Loctite No. 242 blue to nut-side threads.
Tools required
- Hoist Amazon
- Lifting eyes Amazon
- Rubber mallet Amazon
- Hydraulic press or bearing heater Amazon
- Grease gun Amazon
- Alignment pins Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Speed sensor air gap 0.36--0.71 mm (0.014--0.028 in.)
- End bracket clearance 25 mm (1 in.)
- Stator-to-adapter gap 12.7--6.4 mm (1/2--1/4 in.)
Source: Detroit Diesel service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.