Starter - Gasoline Models Ford Thunderbird IX

DESCRIPTION

The starting system includes a 4-pole, 4-brush starting motor with an integral positive engagement drive, a starter-ignition switch, neutral-start switch (some auto. trans. models), starter solenoid (starter relay), and heavy circuit wiring.

Starter motors consists of both 4" and 4 1/2" diameter frames, a movable pole shoe, and appropriate linkage to engage the drive mechanism. Inside the drive assembly, an overrunning clutch prevents starter motor from being driven to excessive speed by the ring gear when the engine starts.

OPERATION

Turning the ignition switch to the "START" position activates the solenoid. The solenoid then connects the battery to the starter.

When the starter is not in use, one of the 4 field coils is connected directly to ground through a set of contacts. When the starter is first connected to the battery, a large current flows through the grounded field coil, activating the movable pole shoe.

The pole shoe, attached to the starter drive plunger lever, engages the drive assembly into the flywheel ring gear. When the movable pole shoe is fully seated, it opens the field coil grounding contacts and the starter operates normally. A holding coil is used to maintain the movable shoe in the fully-seated position while the starter is turning the engine.

ON-VEHICLE TEST INFORMATION

Note. Before performing tests, clean and connect battery cables. Be sure battery is fully charged. Remove coil high tension wire from distributor and ground it. Place transmission in Neutral or Park and apply parking brake. When making voltmeter connections, be sure to connect leads to battery posts or threaded terminals and not just to cable ends.

STARTER CRANKING CIRCUIT TEST - ON-VEHICLE

1. Disconnect ignition coil secondary wire. Connect a remote control starter switch from the positive battery terminal to the "S" terminal of the starter relay.
2. Connect a voltmeter and crank engine as described in each of the following situations. Connect negative voltmeter lead to starter terminal. Connect positive voltmeter lead to positive battery terminal. Voltage drop should be .5 volt. Connect negative voltmeter lead to battery side of starter relay. Connect positive voltmeter lead to positive battery terminal. Voltage drop should be .1 volt. Connect negative voltmeter lead to starter side of starter relay. Connect positive voltmeter lead to positive battery terminal. Voltage drop should be .3 volt. Connect negative voltmeter lead to negative terminal of battery. Connect positive lead of voltmeter to engine ground. Voltage drop should be .3 volt.
3. If any test does not obtain the correct voltage drop, inspect and repair wiring in the starter cranking circuit.

Scheme 1

1. Connect test equipment (Scheme 1) Be sure that no current is flowing through ammeter and heavy duty carbon pile rheostat portion of the circuit. (Scheme 1): Test Equipment Connections for Starter Load Test
2. Disconnect the "S" terminal connector from the starter relay and connect a remote control starter switch. Crank the engine and determine the exact voltmeter reading.
3. Stop cranking the engine and reduce the resistance of the carbon pile until voltmeter indicates same reading as that obtained while starter cranked engine.
4. The ammeter will now indicate starter current draw under load. Normal starter load current is 150-250 amps for 4" starters or 150-210 amps for 4 1/2" starters. If load test current is not within specified range, starter motor must be overhauled or replaced.

STARTER NO-LOAD TEST - BENCH TEST

Note. The starter no-load test will determine such problems as open or shorted windings, rubbing armature, and a bent armature shaft.

Scheme 2

1. Connect positive lead of load tester to positive terminal of a fully charged battery. Connect negative lead of load tester to negative battery terminal. (Scheme 2) (Scheme 2): Test Equipment Connections for Starter No-Load Test
2. Connect voltmeter leads of load tester to positive and negative battery terminals. Connect a jumper wire between negative battery terminal and starter frame. Connect another jumper wire between positive battery terminal and positive terminal of starter motor. (Scheme 2) NOTE: Be sure that no current is flowing through ammeter.
3. Turn rheostat to maximum counterclockwise position. Note the exact voltmeter reading. Disconnect the jumper leads from the starter motor. Reduce resistance of the rheostat until voltmeter reading is the same as when the starter was running. Ammeter will now indicate starter no-load current draw. It should be 80 amps.

ARMATURE OPEN CIRCUIT TEST - BENCH TEST

An open in the armature circuit can be detected by inspecting the commutator for evidence of burning. A spot burned on the commutator is caused by an arc formed every time that segment of the commutator passes under a brush. If burning is detected, replace armature assembly and check for damage to other related components.

ARMATURE & FIELD GROUNDED CIRCUIT TEST - BENCH TEST

Note. This test will determine if winding insulation has failed, permitting a conductor to contact the frame or armature core.

1. Connect negative voltmeter lead to negative battery terminal. Connect positive voltmeter lead to commutator. Connect a jumper wire between positive battery terminal and armature core.
2. If voltmeter indicates any voltage, windings are grounded and armature should be replaced.
3. Connect a jumper wire between negative battery terminal and starter frame. Connect negative voltmeter lead to positive battery terminal. Connect positive voltmeter lead-to-field coil eyelet terminal.
4. If voltmeter indicates any voltage, field windings are grounded and should be replaced.

DISASSEMBLY

1. Remove cover screw, cover, through bolts, starter drive end housing, and starter drive plunger lever return spring. Remove starter gear plunger lever pivot pin and lever. Slide armature out.
2. Remove stop ring retainer, thrust washer, and stop ring from armature shaft. Remove starter drive gear assembly. Remove brush end plate and insulator assembly. Remove brushes from plastic brush holder and lift out holder. Note location of brush holder with respect to end terminal.
3. Remove screws retaining ground brushes to frame. Bend up the edges of the sleeve which is inserted in rectangular hole in frame, remove sleeve and retainer. Detach shunt field coil ground wire from copper tab riveted to frame.
4. Remove the 3 pole shoe retaining screws with Starter Polescrew Tool (10044-A) and an Arbor Press. Cut the field coil connection at the switch post lead. Remove pole shoes and coils from frame. Cut the positive brush leads from the field coils as close to the field connection point as possible.

CLEANING & INSPECTION

Use a brush or compressed air to clean field coils, armature, brush end plate, drive end housing, and starter drive. Wash other parts in solvent.

Inspect armature for open circuits, shorts, grounds and broken or burned insulation. Check commutator for scoring or excessive wear if commutator is rough or more than .005" (.13 mm) out of round, service as necessary. 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" length.

Check field coils for burned or broken insulation and continuity. Replace if open or shorted. Examine wear pattern on start drive teeth, replace if pitted, broken teeth are found. Starter drive teeth must engage ring gear teeth more than 1/2 tooth depth.

Scheme 3

1. Position coils and pole pieces (with coil leads in terminal screw slot), install retaining screws. As screws are tightened, strike frame several times with soft faced hammer to seat and align pole shoes. Stake screws after fully tightened.
2. Install plunger coil sleeve and retainer, bend tabs to retain coils to frame. Position grommet on end terminal and align into notch in frame. Using a 300 watt soldering iron and rosin core solder, solder field coil to starter switch terminal post.
3. Check for continuity and grounds in assembled coils. Position the ground brushes to starter frame and install retaining screws. Apply a thin coat of Lubriplate 777 on armature shaft splines. Install starter motor drive gear assembly to armature shaft, new stop ring, stop ring retainer, and thrust washer.
4. Install armature in starter frame. Position the starter drive gear plunger lever to frame and starter drive assembly. Install pivot pin. Fill drive end housing bearing 1/4 full with grease. Position drive end housing to frame making sure lever return spring engages tang on lever. (Scheme 3): Exploded View of Motorcraft Starter Motor Assembly
5. Install brush holder, brushes, and springs. Positive brush leads should be positioned in their respective slots to prevent potential grounding. Install brush end plate. Ensure that end plate insulator is positioned properly on end plate.
6. Install through bolts to starter frame and tighten to 55-75 INCH lbs (6-8 N.m). Install starter drive plunger lever cover and tighten retaining screw. Check starter no-load current draw. It should be 80 amps.

SPECIFICATIONS

MOTORCRAFT STARTER SPECIFICATIONS