Subaru Legacy BN/BS (2015-2019) Service Manual: Inspection

There is the possibility of damaging the diodes if a mega-tester (used to measure high voltages) or a similar measuring instrument is used. Never use a mega tester or equivalent for this test.

1. Check for continuity between the diode lead and terminal E or B. If continuity is not as shown in the table, replace the rectifier.

1. Slip ring surface

Inspect the slip rings for contamination or any roughness on the sliding surface. Repair the slip ring surface using a lathe or sand paper.

2. Slip ring outer diameter

Measure the slip ring outer diameter. Replace the rotor if the slip ring is worn.

3. Continuity test

Using a circuit tester, check the resistance between slip rings. If the resistance is not within the standard, replace the rotor.

4. Insulation test

Check the continuity between slip ring and rotor core or shaft. If there is continuity, replace the rotor because the rotor coil is grounded.

5. Bearing

Check the bearings. If there is any noise, or the rotor does not rotate smoothly, replace the bearings.

1. Continuity test

Inspect the continuity between the stator coil terminals. If continuity is not as shown in the table, replace the stator coil.

2. Insulation test

Inspect the continuity between the stator coil stator core and lead wire terminals. If there is continuity, replace the stator coil because the stator coil is grounded.

1. Measure the length of each brush. Replace the brush if wear exceeds service limits. There is a service limit mark (A) on each brush.

2. Check that there is appropriate pressure on the brush spring. Using a spring pressure indicator, push the brush into the brush holder until its tip protrudes 2 mm (0.0787 in). Then measure the pressure of brush spring. If the pressure is 1.7 N (173 gf, 6.11 ozf) or less, replace the brush spring. 4.1 — 5.3 N (418 — 540 gf, 14.75 — 19.06 ozf) pressure is required on the new spring.