Starter - Motorcraft Ford Bronco II I

DESCRIPTION

Unit is a 4-pole, 4-brush starter with 3 series coils and one shunt coil. Shunt coil is wound around the pole piece, which operates integral positive engagement drive mechanism.

LOAD TEST

1. Connect a tester and battery into starter circuit. (Scheme 1) Crank engine with ignition coil secondary wire grounded and note voltage on tester.
2. Stop cranking engine and turn load control knob until voltage reading is exactly the same as it was when engine was cranking. Read current draw on ammeter scale. If not within specifications, starter is defective and must be overhauled.

LOAD TEST SPECIFICATIONS

LOAD TEST SPECIFICATIONS

Scheme 1

NO-LOAD TEST

1. With tester and battery connected to starter, operate starter motor and note voltage reading and tachometer reading. (Scheme 2) Disconnect starter from the battery. Turn load control knob until voltage reading is same as when starter is connected.
2. Read amperage draw, and if amperage reading is less than specifications, starter has high electrical resistance. If starter RPM is less than specifications, starter has high electrical resistance. If starter RPM is less than specifications, starter has worn bushings or bent armature shaft.

NO-LOAD SPECIFICATIONS

NO-LOAD SPECIFICATIONS

Scheme 2

ARMATURE OPEN CIRCUIT TEST

An armature with an open circuit can sometimes be detected by checking the commutator for signs of burning. A spot burned on the commutator is caused by an arc formed every time the commutator part connected to the open circuit wiring passes under a brush.

ARMATURE & FIELD GROUNDED CIRCUIT TEST

Connect voltmeter and battery terminals. (Scheme 3) If voltmeter shows any voltage, windings are grounded.

Scheme 3

DISASSEMBLY

1. Remove cover screw, cover, through bolts, starter drive end housing and starter drive plunger lever return spring. Remove pivot pin retaining plunger lever and remove plunger lever and armature.
2. Remove stop ring retainer and stop ring from starter drive gear and starter drive gear assembly. Remove brush end plate and insulator assembly. Remove brushes from brush holder and lift out brush holder. Note location of brush holder with respect to end terminal.
3. Remove ground brushes-to-frame retaining screws. On field coil which operates drive gear actuating lever, bend edges on field coil retaining sleeve and remove sleeve and retainers.
4. Remove 3 coil retaining screws with Generator Pole Screw Wrench (10044-A) and an arbor press. Cut field coil connection at switch post lead and remove small diameter ground wire from upper tab riveted to frame.
5. Remove pole shoes and coils from frame. Cut positive brush leads from field coils as close to field connection point as possible.

Brushes & Springs

1. Check brush holders for broken springs and insulated brush holders for shorts to ground. Tighten any loose rivets. Replace brushes if worn to 1/4" (6.35 mm) in length. Measure spring tension with spring scale hooked under spring near end.
2. Pull on line parallel to edge of brush and note reading just as spring end leaves brush. Spring tension should be 80 ozs. (2.263 kg). When replacing brushes, use a 300-watt soldering iron and rosin core solder.

Scheme 4

Scheme 5

Field Coil Assembly

Inspect field coils for burned or broken insulation and continuity. Check field brush connections and lead insulation. Check for grounds in field windings.

Armature

1. Check armature for shorted coils with a growler and a test light. Touch one test lead to armature core and other to each commutator bar one at a time. If light lights, armature is shorted to ground and must be replaced.
2. Place switch on growler in "GROWLER" position and hold steel blade parallel to and touching armature core. Rotate armature and if blade vibrates at any point, that area is shorted and armature must be replaced.
3. Inspect armature shaft for excessive wear. Inspect windings for broken or burned insulation. If commutator is rough or more than .005" (.13 mm) out of round, turn down in a lathe, removing only enough material to provide a smooth, even surface.

REASSEMBLY

1. Position 3 coils and pole pieces and install attaching screws. As pole shoe screws are tightened, strike frame with a soft hammer to seat and align pole shoes, then stake screws.
2. Install remaining coil and retainer. Bend tabs to secure coil to frame. Position new field brush lead on field coil terminal. Install clip to hold brush lead to terminal. Solder lead, clip and terminal together with a 300-watt soldering iron and rosin core solder.
3. Ground coil around retaining sleeve by positioning small diameter wire leading from coil under copper tab which attaches contact to frame. Install ground brushes to frame with screws.
4. Lubricate armature shaft splines with Lubriplate. Install drive gear assembly on armature shaft. Install new retaining stop ring and stop retainer.
5. Install armature in frame. Partially fill drive end housing bearing bore with grease. Position drive gear plunger lever to frame and starter drive assembly and install pivot pin.
6. Install plunger lever return spring and drive end housing to frame. Install brush holder, brushes and springs. Install brush holder insulator.
7. Position end plate to frame and align plate locator with frame slot. Install and tighten through bolts to 55-75 INCH lbs. (6-8 N.m). DO NOT pinch brush leads when installing end plate. Position drive gear plunger lever cover on starter and tighten cover screw.