Starter - Delco-Remy GMC Cab & Chassis R2500

DESCRIPTION

Starter has a solenoid pinion shaft (overrunning clutch) with entire mechanism enclosed within housing. Starter solenoid is flange mounted on drive end housing and has a compression-type return spring located inside solenoid case.

TROUBLE SHOOTING

Note. See the TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL TROUBLE SHOOTING section.

SOLENOID WINDING TESTS

Tests are performed with all leads disconnected from solenoid. Complete tests in minimum amount of time to prevent solenoid from overheating.

Hold-In Winding (All Models)

1. Connect an ammeter, voltmeter, carbon pile and battery into starter circuit. (Scheme 1) Connections shown in dashed lines are used only for pull-in winding testing. Using carbon pile, decrease battery voltage to 10 volts for GM models.
2. Ammeter should read 14.5-16.5 amps for GM models. Higher reading indicates winding is shorted or grounded. Lower reading indicates excessive resistance.

Both Windings in Parallel (GM Only)

Using same connections as hold-in winding test, ground "M" terminal. Using carbon pile, adjust voltage to 10 volts. Amperage draw should be 41-47 amps.

Note. Use carbon pile between battery and "M" terminal if it is required to reduce voltage to specified testing voltage. If not, connect jumper directly from battery to "M" terminal.

Scheme 1

STARTER NO LOAD TEST

1. Connect a tachometer, ammeter and voltmeter into start circuit. (Scheme 2) Adjust carbon pile to specified voltage indicated in table.
2. Read current draw and armature speed to ensure they are within specification. DO NOT apply voltage greater than specified, as excessive voltage may cause armature to throw windings due to excessive speed. Refer to the «STARTER NO-LOAD SPECIFICATIONS»(/gmc/cab-chassis-r2500/1987-1987/remont/starter/#starter-delco-remy) table.
3. Low free speed and high current draw indicates too much friction, shorted armature, or grounded armature or fields. Failure to operate with high current draw indicates a direct ground in terminal or fields, or frozen bearings.
4. Failure to operate with no current draw indicates an open field, open armature coils, broken brush springs, worn brushes, or high commutator insulation.
5. If no-load speed is low and there is low current draw, suspect high internal resistance due to poor connection, defective leads, or dirty commutator. A high free speed and high current draw usually indicates shorted fields.

Scheme 2

ARMATURE

Test armature for shorted coils with a growler. Check for grounded coils using a self-powered test light. Place one test lead on armature core or shaft, and other test lead on commutator. Lamp should not light. If lamp lights, armature is grounded and should be replaced.

FIELD COILS

1. Using self-powered test light, place one test lead on field coil terminal strap, and touch other test lead to field coil brush lead (check series coils and shunt coils separately at appropriate terminals).
2. Lamp should light. If lamp does not light, coils are open. Check for grounds by placing one test lead on field armature strap, and touch other lead to armature core or shaft. If lamp lights, one or more coils are grounded.

Replace brushes if worn to 1/2 original length, oil-soaked or pitted. Check brush spring tension and replace springs if weak or distorted. Deformed or bent brush holders can be replaced by service units which are installed with screws and nuts.

DRIVE & PINION

Pinion should turn freely in overrun direction and should not slip in drive direction. Check spring for correct tension and drive collar for wear (these parts can be removed for replacement by forcing collar toward clutch and removing lock ring from end of tube). Replace drive assembly if pinion teeth are worn, chipped, or cracked.

Scheme 3

PINION CLEARANCE

1. Disconnect motor field coil connector and insulate it carefully. Connect a battery from solenoid switch terminal to solenoid frame. Momentarily flash a jumper lead from motor terminal to solenoid frame.
2. This shifts pinion into cranking position. Push pinion back toward commutator end to eliminate slack. Measure distance between pinion and pinion stop. When installing starter, check clearance between pinion and flywheel ring gear teeth. Refer to the «PINION CLEARANCE SPECIFICATIONS»(/gmc/cab-chassis-r2500/1987-1987/remont/starter/#starter-delco-remy) table.
3. Insert a .020" (.60 mm) diameter wire, about 3" (76 mm) long, with a 1/4" to 1/2" 90 degree bend in end between pinion tooth and ring gear. Center pinion tooth between flywheel teeth when making measurement.

DISASSEMBLY

1. Disconnect field coil connector from solenoid motor terminal. Remove solenoid mounting screws and rotate solenoid 90 degrees. Remove solenoid and solenoid plunger spring.
2. Remove 2 through bolts, commutator end frame, field frame assembly and washer. On diesel models, remove insulator. On gasoline models, remove armature assembly from drive housing and thrust collar from armature shaft.
3. On diesel models, remove shift lever pivot bolt, center bearing screws and drive gear housing from armature shaft. Shift lever and plunger assembly will now fall away from starter clutch.
4. On gasoline models, slide a 5/8" deep socket over pinion shaft. Using a hammer, strike socket against retainer to drive retainer off snap ring. Remove snap ring from groove in armature shaft.
5. On diesel models, remove retainer, clutch assembly, fiber washer and center bearing. Remove roll pin, shift lever and plunger. On gasoline models, roller clutches are serviced as an assembly.

CLEANING

Clean all parts with a clean cloth. DO NOT clean armature, field coils, or drive assembly in any type of grease dissolving solvent as this will damage insulation and wash lubricant out of drive assembly.

Scheme 4

Scheme 5

1. On diesel model starters, assemble armature and clutch by lubricating drive end of armature shaft with silicone lubricant. Install center bearing, fiber washer and clutch assembly onto armature, with pinion away from armature. (The 5MT and 10MT starters appear similar to the 27MT starter, except have no center bearing.) Slide retainer onto shaft and install snap ring and thrust washer.
2. Position retainer, thrust washer and snap ring. Using pliers, grip retainer and washer and squeeze until snap ring is forced into retainer and is held in groove in armature shaft.
3. On all models, lubricate drive gear housing bushing with silicone lubricant. Engage shift lever yoke with clutch and slide complete assembly into drive gear housing.
4. Install center bearing screws and shift lever pivot bolt. Tighten securely. Install solenoid assembly on drive gear housing. Apply Sealer (1050026) to solenoid flange where it meets drive housing and field frame. Use care not to damage brushes.
5. Position field frame against drive gear housing on alignment pin, using care not to damage brushes. Lubricate commutator end frame bushing with silicone lubricant. Install washer on armature shaft and slide end frame onto shaft and install through bolts.
6. On diesel models, install insulator and end frame onto shaft. Install through bolts, ensuring they pass through bolt holes in insulator. Connect field coil connector to solenoid terminal. Check pinion clearance as outlined in OVERHAUL and TESTING.

Scheme 6

SPECIFICATIONS

STARTER NO-LOAD SPECIFICATIONS (1)

PINION CLEARANCE SPECIFICATIONS

See also:
• TROUBLE SHOOTING - BASIC PROCEDURES
• STARTER NO-LOAD SPECIFICATIONS