28 MT starter
Contents
1. NeicoRemy 1 128 PRODUCT INFORMATION 1 98 MIT MEDIUM DUTY STARTER SERVICE MANUAL 1998 Delco Remy Intemational Inc All Rights Reserved FEATURES Totally Enclosed Shift Mechanism e Solenoid Operated Shift Lever e Ring Seals e Solenoid Sealing Boot Sealed Solenoid e Layered Wound Coil e Waffle Design Contact Face E Bearing Lubrication and Sealing e Ball Bearing at Commutator End e Bronze Sleeve Bushing in Drive Housing e Sealing for Wet Clutch Applications Available Medium Duty Drive e Positive Shift Overrunning Clutch e Five Roll Speed RPM X 1000 28 MT Torque lb ft Cranking Motor Performance 12V 25 C 0 200 400 600 800 1000 1200 1400 180 0 mm Gear Reduction e Gear Ratio 3 875 1 e Two Ball Bearings E Long Life Brushes e Four One Piece Brushes e Constant Pressure Brush Springs e Radialine Brush Holders e Heavy Brush Leads High Reliability Armature e Molded Bar Commutator e Steel Banded e Varnish Impregnated e Dynamically Balanced Field Coils e Nomex Covered Conductors e Insulated Between Coils and Pole Shoes E Medium Duty Applications e Diesel Powered Light Trucks e Diesel Passenger Cars e Low Range Diesel Engines Specifications e Diesel Engine Size Up to 6 5 liters System Voltage 12 V or 24 V Rotation Clockwise Mounting S A E 1 2 3 4 Automotive Type Pad Mount Pinion Data S A E No T2. O ring 20 28 MT STARTER IMPORTANT e O ring can easily be damaged during installation of the C E frame 14 To prevent such damage install O ring as described in the following steps e Install O ring on frame field and brush holder group A so that it is against the shoulder on the field frame that will abut the C E frame when installed This is the normal installed position for the O ring e Carefully roll the O ring out of its normal installed position up onto the major OD of the field frame Allow O ring to remain in this position until C E frame is partially installed 6 C E frame 14 e Align marks on C E frame and frame and field assembly 19 Figure 8 make prior to disassembly e Start C E frame onto frame and field assembly leaving a gap just slightly larger than the thickness of O ring 20 7 Brush plate screw 42 e Use a scribe or similar tool to align tapped holes in brush holder assembly 3 Figure 8 with screw holes in C E frame 14 TIGHTEN e Brush plate screws to 2 8 N m 25 Ib in 8 Thru bolts 41 e Install thru bolts and tighten by hand but do not close gap between C E frame and frame and field assembly where O ring 20 goes e Roll O ring 20 back down into its installed position between C E frame and frame and field assembly e Align timing ribs on edge of C E frame 14 with timing spots on frame and field assembly A to assure proper brush alignment Refer to Fi
3. MT 24 volt models have these No Load Test Specification RPM Minimum Maximum Minimum Maximum 28 MT Starter Solenoid current consumption Rated Pull in Winding Hold in Winding Voltage Amps Ohms Amps Volts 10 24 100 125 0 16 0 20 12 14 20 1 15 1 65 For further information on rotations and exact specifications on these or other Delco Remy America Products Call 1 800 DRA 0222 I Inc iona 2902 Enterprise Drive Delco Remy Internat Anderson IN 46013 these and other ions on 1 800 DRA 0222 t d spec formation an Delco Remy Products call In For further 1 HRY 1 fi 2 j Aes Copyright DRI 1M 128 10 97 Ico Rem ION d by General Motors Corporati icense tered trademark y Is IS De Pa
4. contacts side not end of brush see Figure 17 This will hold brushes retracted until after brush holder is installed Over armature commutator 3 Grounded brush screws 39 e Position terminals of grounded brush leads behind terminal tabs on brush holder 3 see Figure 17 28 5123 e Insert brush screws 39 through terminal tabs on brush holder and thread into brush lead terminals BRUSH HOLDER ASSEMBLY SPRING SPRING POST SOCKET Figure 16 Brush Spring on Post TIGHTEN INSTALL OR CONNECT e Grounded brush screws to 1 5 N m 13 Ib in 1 Brush springs 7 if removed e Start each brush spring onto post on brush holder assembly 3 as shown in Figure 16 just enough to hold inside end of spring from turning e Grasp free end of spring with needle nose pliers and twist clockwise over top of brush socket e Push spring fully onto post and release free end to engage notch in brush socket INSULATED BRUSH Z _ o o F BRUSH SOCKET INSULATION BRUSH GROUNDED BRUSH i SPRING TERMINAL N POST TAB BRUSH HOLDER GROUNDED ASSEMBLY api BRUSH SCREW 28 5124 Figure 17 Springs and Brushes on Brush Holder PAGE 18 1M 128 4 96 4 Frame and field assembly 19 to brush holder assembly e Position brush holder assembly 3 with installed brushes over terminal end of frame and field assembly 19 e Attachterminals of insulated brush leads to conductors i
5. drive housing 18 aligning holes in drive shaft support 17 Figure 10 with those in drive housing e Make sure that drive shaft support is fully seated in drive housing and that drive shaft bearing 10 Figure 10 remains fully seated in drive shaft support 4 Shift lever screw 21 washer 22 and nut 23 S TIGHTEN e Nut to 4 5 N m 4016 in 5 Plate 26 if used and drive housing plug 27 to drive housing 18 6 Washers 30 through 32 in same number and position as noted at disassembly 7 Armature support bracket 16 to drive housing 18 aligning mark made prior to disassembly with that on drive housing 8 Drive housing bolts 36 and 37 METAL BLOCK APPROX 9 MM 3 16 IN APPROX 38 MM 1 1 2 IN 0 56 IN Bolts 36 and 37 to 8 5 Nm 75 lb in 28 MT STARTER 1M 128 4 96 PAGE 17 ASSEMBLY OF FRAME FIELD AND 2 NOTICE Brush leads may be damaged by excessive BRUSH HOLDER GROUP handling Do not over flex leads near clip welds or clips may break off Figures 8 16 and 17 Brushes 4 and 5 if removed e See Figure 17 for proper installed position of all brushes Make sure insulated brushes 5 go into brush sockets of brush holder assembly 3 that are mounted on insulation e install each brush grasp free end of brush spring with needle nose pliers twist clockwise to clear brush socket and insert brush partly into brush socket e Gradually release spring so that its end
6. inspecting the points where the armature conductors join the commutator A poor connection often will be indicated by signs of arcing or burning of the commutator e Replace armatures which are shorted grounded or show evidence of opens 3 Check frame and field assembly 19 for grounds or opens using test lamp 110 volts max or ohmmeter as follows e Check that there is continuity no opens between the field terminal that connects to the solenoid and the connection points for insulated brushes on the field coil straps e Check that thereis nocontinuity no grounds between the frame and the field terminal that connects to the solenoid e Replace frame and field assemblies that have grounds or opens 28 MT STARTER BATTERY SWITCH TERMINAL TERMINAL 28 5119 INSULATED BRUSH CONNECTIONS FRAME AND FIELD ASSEMBLY 28 5120 Figure 13 Frame and Field Assembly 28 MT STARTER IM 128 4 96 PAGE 15 REPAIR PROCEDURES REMOVE OR DISCONNECT Figures 6 and 14 1 If necessary replace bearings 8 and 9 Figure 6 on e Center support bearing 10 from drive shaft 15 using locally fabricated tool as shown in Figure 14 armature 13 as follows INSTALL OR CONNECT NOTICE Ball bearings which areremoved from armature must be replaces with new bearings Removal procedure causes internal damage to bearings REMOVE OR DISCONNECT e Center support bearing 10 from drive shaft 15 using locally fabricated
7. the battery circuit is noted when making connections the starter solenoid switch contacts may be frozen shut refer to Table 1 Troubleshooting BATTERY CARBON PILE R P M INDICATOR IM 128 4 96 PAGE 5 5 As the laststep in making the test connection ground the negative battery cable securely to a clean metal ground on the starter frame 6 The carbon pile load is used to adjust operating voltage for comparison with specifications It may not be necessary in all cases but should be used to eliminate the need for interpolation of test data TEST PROCEDURE CAUTION Keep fingers and tools away from opening in D E drive end housing while testing The strong shifting action of the solenoid could cause personal injury or damage as the drive pinion moves into the cranking position and spins NOTICE During no load test close switch and operate starter for cycles of 30 seconds maximum Between cycles allow starter to cool for at least two minutes Otherwise overheating and damage to the starter may result VOLTMETER CLAMP ON AMMETER 28 5112 Figure 5 Starter No Load Test Hook Up PAGE 6 1 128 4 96 1 Momentarily close switch e If there is high current flow and starter fails to Operate zero rpm release switch immediately Internal mechanical damage is indicated Discontinue test and refer to Table 1 Troubleshooting e Ifthereis no current flow and starter fails to operate zero rpm release swi
8. D REPAIR CLUTCH DRIVE ASSEMBLY 15 DRIVE SHAFT CENTER SUPPORT 17 DRIVE SHAFT BEARING SUPPORT _ PINION STOP 35 STOP RINGS 2 PCS 28 5117 Figure 10 Drive Shaft and Clutch Group 28 MT STARTER CLEANING INSPECTION AND REPAIR CLEANING NOTICE Do not clean or immerse starter parts in grease dissolving solvents Solvents will dissolve grease packed in drive assembly and may damage armature or field coil insulation CLEAN 1 All starter parts with a soft cloth prior to testing INSPECTION Figure 6 Inspection in the following steps refers to visual inspection of starter parts and assemblies to determine their serviceability Electrical tests for certain assemblies are described in COMPONENT ELECTRICAL TESTING INSPECT 1 All parts forcracks distortion or other structural damage Replace parts or assemblies which are cracked bent or otherwise damaged 2 Threaded parts for stripped crossed or otherwise damaged threads Replace parts with thread damage that cannot be cleaned up using a suitable tap or die Replace any hardware items that have damaged threads 3 Solenoid assembly 1 for cut or torn boot If boot is damaged replace solenoid assembly 4 Clutch drive assembly 2 for the following Replace clutch drive assembly if damaged e Pinion gear turns roughly or turns in both directions e Pinion gear teeth broken or showing evidence of step wear e Deep scoring or other damage to shift
9. H SPRING 39 GROUNDED BRUSH SCREW 28 5115 Figure 8 Frame Field and Brush Holder Group 28 MT STARTER DISASSEMBLY OF GEAR REDUCTION AND DRIVE GROUP Figure 9 REMOVE OR DISCONNECT 1 Housing bolts 36 and 37 2 Armature support bracket 16 IMPORTANT e Washer 30 through 32 may stick to armature support bracket or to drive shaft and clutch group as armature support bracket is removed In either case note the position and number of each of these washers D E HOUSING BUSHING SHIFT LEVER ARMATURE SUPPORT BRACKET DRIVE HOUSING WASHER THICK SHIFT LEVER SCREW BUSHING PLUG IF SHIFT LEVER WASHER USED 1M 128 4 96 PAGE 11 3 Washers 30 through 32 e Save washers to be installed in the same position and number at assembly 4 Drive housing plug 27 and plate 26 e Pry outdrive housing plug using a large screwdriver 5 Shift lever nut 23 washer 22 and screw 21 6 Shift lever 11 and drive shaft and clutch group C from drive housing 18 together then separate e Do not remove bushing plug 34 or bushing 6 from drive housing 18 unless replacement is required refer to CLEANING INSPECTION AND REPAIR SHIFT LEVER NUT DRIVE HOUSING BOLT PLATE IF USED LONG DRIVE HOUSING PLUG DRIVE HOUSING BOLT WASHER FIBER SHORTER ON SOME MODELS WASHER THIN ONE OR DRIVE SHAFT amp CLUTCH TWO MAY BE USED GROUP 28 5116 Figure 9 Gear Reduction a
10. Refer to UNIT REPAIR section for required disassembly inspection test and if necessary repair or replacement instructions PAGE 8 1 128 4 96 UNIT REPAIR NOTICE Always install fasteners at original location If necessary to replace fasteners use only correct part number or equivalent If correct part number is not available use only a fastener of equal size and strength refer to Delco Remy America Standard Hardware Fasteners section in Service Parts Catalog Use a torque wrench to tighten fasteners when a torque value is specified in these instructions or in the vehicle or engine manufacturer s instructions Torques specified are for dry unlubricated fasteners unless otherwise specified INTRODUCTION Figure 6 Figure 6 illustrates the starter broken down into component parts and assemblies Index numbers on Figure 6 correspond to those used in the Delco Remy America Service Parts Catalog Do no attempt to disassemble the following components which are serviced as assemblies solenoid assembly 1 clutch drive assembly 2 brush holder assembly 3 armature assembly 13 frame and field assembly 19 This section provides instructions for complete disassembly of the starter as would be the case for overhaul If the starter is not due for overhaul and repair affecting specific parts only is required the starter may be disassembled only to the extent necessary to gain access to these parts Parts removed from the starter
11. S OF INSTALLED BOLTS SHOULD PASS THROUGH From inside drive housing 18 drive out plug 34 if present Use file to clean away remnants of old stake to allow installation of new plug Clean away any metal shavings Using suitable open tube press out bushing 6 Using suitable open tube press new bushing 6 into drive housing 18 until end of bushing is flush with inside of housing Install new plug 34 if used to drive housing Stake housing material over plug at three places equally spaced LOCALLY FABRICATED f WIDE END OF DRIVE SHAFT ACCESS CENTER SUPPORT BEARING CENTER i SUPPORT SHAFT FIXTURE ACCESS HOLES IN END OF DRIVE SHAFT WITHOUT BINDING 28 5121 Figure 14 Tool for Removing Center Support Bearing PAGE 16 7M 128 4 96 ASSEMBLY LUBRICATION DURING ASSEMBLY Armature bearings 8 and 9 Figure 6 and drive shaft support bearing 10 are permanently lubricated Do not add lubricant to these bearings Using Delco Remy America Lubricant No 1960954 lubricate the following just before or during assembly avoid excessive grease e D E housing bushing 6 in drive housing e Pivot hole and working surface on ends of shift lever 11 e Internal gear shaft and spline on drive shaft 15 DRIVE SHAFT AND CLUTCH GROUP Figures 10 and 15 If disassembled position drive shaft on work surface with internal gear end down and assemble drive shaft and clutch group as fo
12. SCREW 34 28 5113 Figure 6 Starter Assembly PAGE 10 1M 128 4 96 SOLENOID ASSEMBLY D E ARMATURE BEARING C E ARMATURE BEARING ARMATURE ASSEMBLY C E FRAME FRAME O RING SOLENOID SCREW DOWEL PIN FRAME SEAL THRU BOLT BRUSH PLATE SCREW FRAME FIELD amp BRUSH HOLDER GROUP GEAR REDUCTION amp DRIVE GROU 28 MT STARTER 28 5114 Figure 7 Electrical Group DISASSEMBLY OF FRAME FIELD AND BRUSH HOLDER GROUP Figure 8 REMOVE OR DISCONNECT 1 oS Insulated brush screws 29 Move brush holder assembly 3 with brushes 4 and 5 away from frame and field assembly 19 slightly to reach across with screwdriver and remove screws 29 Frame and field assembly 19 Grounded brush screws 39 Brushes 4 and 5 if replacement is required e Grasp brush end of each brush spring 7 with needle nose pliers twist spring end away from brush 4 or 5 and withdraw brush Brush springs 7 if replacement is required e Grasp brush end of each brush spring 7 with needle nose pliers twist spring end away from brush socket on brush holder assembly 3 and remove spring NOTICE At this stage of disassembly all electrical components can be inspected and if required independently tested as specified in CLEANING INSPECTION AND REPAIR BRUSH HOLDER FRAME amp FIELD ASSEMBLY INSULATED BRUSH BRUSH GROUNDED BRUSH INSULATED SCREW BRUS
13. as subassemblies or groups need not be disassembled for such limited repair unless they contain the affected parts Total disassembly is recommended however to ensure that all parts can be thoroughly cleaned and inspected In this section the starter is broken down by main groups These groups are then disassembled into individual parts and assemblies Illustrations accompany the text to show specific operations To see the parts relationship of the complete starter refer back to Figure 6 DISASSEMBLY Make a mark completely down one side of the starter to ensure proper alignment of all components at assembly Use colored pencil or marker that will show on all parts Disassemble as follows 28 MT STARTER UNIT DISASSEMBLY Figure 7 REMOVE OR DISCONNECT 1 Motor lead on frame field and brush holder group A from solenoid assembly 1 Reinstall nut on solenoid terminal e Remove nut on solenoid slip off motor lead and reinstall nut 2 Thru bolts 41 Brush plate screws 42 4 C E frame 14 and O ring 20 IMPORTANT In the following step use care not to loose the small dowel pin 28 installed between frame field and brush holder group A and gear reduction and drive group B Dowel pinis required for assembly and must be saved If dowel pin should be lost it must be replaced with 2 mm 0 079 in dia x 10 mm 0 394 in long pin procured or manufactured locally 5 Frame field and brush holder gro
14. ce of step wear e Damaged spline Clutch drive assembly must slide smoothly and easily over full length of spline PAGE 14 1 128 4 96 COMPONENT ELECTRICAL TESTING Figures 12 and 13 Perform the following electrical tests on the solenoid assembly 1 armature assembly 13 and frame and field assembly 19 to determine their serviceability 1 Using a suitable ohmmeter check windings of solenoid assembly 1 for continuity as follows e Check resistance of solenoid pull in and hold in windings in series by measuring resistance between motor terminal see Figure 12 and solenoid case Resistance should be approximately 0 95 ohms for 12 volt starters and approximately 1 75 ohms for 24 volt starters e An extremely high resistance reading indicates a break or fault in winding continuity A very low resistance reading indicates a short or ground in the winding circuit Either condition is cause for replacement of the solenoid assembly 2 Check armature 13 as follows for shorts opens or grounds using suitable test equipment and instruments test lamp must be 110 volts or less e Rotate armature in a growler holding a steel strip such as a hacksaw blade against the armature If a short circuit is present the steel strip will vibrate in that area e Check the armature for grounds using a test lamp or ohmmeter There shall be no continuity between the armature shaft and any point on the commutator e Check for opens by visually
15. e One or more control switches may be used in series with the start switch to prevent cranking the engine unless certain system conditions are met Refer to the specific vehicle wiring diagram to see what other cranking controls may be used A typical example of a control switch is a neutral safety switch that prevents cranking unless the transmission is in neutral In 12 volt systems the relatively low current in the S terminal circuit may be handled directly by the start switch However higher current levels in 24 volt systems always require that the start switch operate a separate magnetic switch in the 5 terminal circuit SOLENOID PLUNGER START SWITCH SOLENOID HOLD IN COIL SHIFT LEVER SOLENOID PULL IN COIL 9 FLYWHEEL SOLENOID SWITCH FIELD COIL ARMATURE DURING CRANKING 28 5105 Figure 3 Starter Electrical Schematic PAGE 4 1 128 4 96 28 MT STARTER START SWITCH BATTERY 5 N CONTROL SWITCH SOLENOID 5 la onus 28 5111 Figure 4 Starter Wiring Circuit TROUBLESHOOTING ON VEHICLE SERVICE To independently test the starter it is necessary to remove it from the engine However before doing this checks should be made to ensure that the problem is with the starter and not with the engine battery wiring or switches When the other possible problem sources have been eliminated then remov
16. e and test the starter Comparison of test results with the Troubleshooting Chart Table 1 will aid in isolating the problem within the starter to specific components This will determine the repair or repairs needed to restore the starter to serviceability BATTERY TEST Realistic testing as well as successful operation requires a fully charged battery capable of supplying the current needs of the starting system Step one in troubleshooting the starting system is to test the battery Follow vehicle or battery manufacturer s instructions such as Delco Remy America bulletins 1B 115 and 1B 116 WIRING AND SWITCHES VISUAL INSPECTION Visually inspect all wiring and switches in the starting circuit for damage and loose or corroded connections This includes all ground connections Clean and tighten connections as required Replace damaged wiring or components CONTINUITY CHECK Set parking brake and or block wheels to prevent movement of vehicle during checks Disconnect field lead on starter from solenoid M terminal and insulate carefully to prevent accidental contact Set manual transmission to neutral and depress clutch or place automatic transmission in Park Use voltmeter to check for voltage at solenoid S terminal while start switch is held in Start position If voltage is not present at S terminal use voltmeter and vehicle manufacturer s wiring diagram to trace control circuit and locate point of voltage loss and corr
17. ect as necessary For further information on general diagnosis of starter control circuit refer to Delco Remy America publication DRA DP 1029 STARTER REMOVAL If the battery wiring and switches are in satisfactory condition and the engine is known to be functioning properly remove the starter for further testing Refer to the vehicle or engine manufacturer s instructions for the proper removal procedure 28 MT STARTER STARTER NO LOAD TEST GENERAL INFORMATION With the starter removed from the engine the no load test can reveal damage that can be corrected by repair or it may indicate the need for component testing after the starter is disassembled Repair and component test procedures are described in the UNIT REPAIR section The no load test is also used to test units for normal operation after repair or Overhaul Comparison of test results with the Troubleshooting Chart Table 1 will indicate what corrective action if any is required TEST HOOK UP Figure 5 Connect the starter for the no load test as shown in Figure 5 using suitable instruments battery cables and connecting wiring Note the following 1 Secure starter in suitable test stand to check operation 2 Use a momentary contact pushbutton switch in the test circuit for quick release if very high current surges are encountered 3 Make all connections or disconnections with the switch open and the carbon pile load turned off 4 If sparking or current flow in
18. ed light trucks and passenger cars and other low range diesel engines Weighing just 8 kg 17 6 1b the 28 Figure 1 28 MT Starter MT produces up to 3 kilowatts of output Models are available for either 12 or 24 volt systems with clockwise rotation PAGE 2 1 128 4 96 SOLENOID CONTACT DISC ARMATURE BALL BEARING j g ama Rn T wast if fafi i 11 y lll uf BALL BEARING ARMATURE GEAR SOLENOID ASSEMBLY 28 MT STARTER PLUNGER SPRING SEALING BOOT SOLENOID PLUNGER SHIFT LEVER CLUTCH DRIVE ASSEMBLY DRIVE END PINION BUSHING Ta Z A iS INTERNAL GEAR BALL BEARING 28 5105 Figure 2 Starter Cross Section The 28 MT has a totally enclosed solenoid operated mechanism for positive shift of the pinion into engagement The solenoid is sealed to prevent entry of foreign material Within the solenoid waffle type contact faces and a solid link between the contact disc assembly and the solenoid plunger help prevent contact sticking The shift lever is attached to the plunger on one end and mates with a collar on the drive assembly at the other end The action of the lever forces the drive pinion into engagement with the engine flywheel when the magnetic pull of the solenoid draws the plunger in A medium duty 5 roll overrunning drive is used for low overrun friction a
19. eeth Pinion Blank Pitch 10 11 10 12 10 11 8 10 12 13 8 10 Weight 8 0 kg 17 6 lbs 338 3 mm 28 5109 28 MT STARTER 1M 128 4 96 PAGE 1 PRODUCT INFORMATION AND SERVICE MANUAL 28 MT STARTER CONTENTS Modoc le ee erence tern et E 1 Ui REDA E 8 General seeen 1 8 Operan Principles 3 Pisasse D e eaten tens 8 Troubleshooting i 4 Cleaning Inspection and 13 On Vehicle 4 UnC Assembly soeces iser nnn are 16 Battery Tests Starter Installation 19 Wiring and Switches 4 Starter Removal 4 Starter No Load 5 amp cresci 6 INTRODUCTION This publication covers the Delco Remy 28 MT Starter see Figure 1 As listed in the CONTENTS descriptive information and instructions for testing troubleshooting removal unit repair and installation are provided For parts information refer to the Delco Remy America Service Parts Catalog GENERAL DESCRIPTION Figures 1 and 2 The 28 MT starter provides high starting torque in a compact lightweight package by using a high speed motor through an offset gear reduction unit The 28 MT 15 suitable for medium duty applications such as diesel power
20. gure 18 Marks are located in 2 places on motor but will only match one way TIGHTEN e Thru bolts 41 to 8 5 75 1b in 9 Motor lead on frame and field assembly 19 Figure 8 e Remove nut from terminal on solenoid install motor lead terminal and reinstall nut S TIGHTEN e Nuton terminal of solenoid assembly to 11 N m 100 lb in 28 MT STARTER STARTER INSTALLATION TESTING AFTER REPAIR OR OVERHAUL After repair or overhaul the starter can be tested as specified in the Starter No Load Test found in the TROUBLESHOOTING section After repair overhaul testing or replacement of the starter refer to the vehicle or engine manufacturer s instructions for the proper installation procedure Use the following torques when making electrical connections to starter CAUTION Make sure negative battery cable is disconnected at battery when making electrical connections to starter Otherwise injury may result If a tool is shorted at the solenoid battery terminal the tool will heat enough to cause a skin burn TIGHTEN e Solenoid battery terminal nutto 18 N m 13 Ib ft e Solenoid switch S terminal nut to 1 8 N m 16 lb in 1M 128 4 96 PAGE 19 C E FRAME TIMING MARKS FRAME AND FIELD ASSEMBLY 28 5125 Figure 18 Aligning Timing Marks PAGE 20 1M 128 4 96 28 MT STARTER SPECIFI All 28 MT 12 Volt models have these No Load Test Specifications 125 190 3000 5600 All 28
21. lever collar 1M 128 4 96 PAGE 13 5 Brush holder assembly 3 for the following Replace brush holder if damaged e Loose riveted joints e Cracked or broken insulation 6 Brushes 4 and 5 for excessive wear e Minimum allowable brush length is 12 mm 0 472 in Replace excessively worn brushes in sets 7 D E housing bushing 6 for scoring or other damage Replace damaged bushing refer to REPAIR following 8 Ball bearings 8 9 and 10 as follows e Hold armature 13 or drive shaft 15 and slowly rotate outer bearing race by hand e Check that bearing turns freely without binding or the feel of flat spots e Replace damaged bearings refer to REPAIR following 9 Armature assembly 13 for the following e Gear teeth that are broken or that show evidence of step wear or root interference e Rough commutator surface Polish with No 400 grit polishing cloth if necessary Thoroughly clean metal dust from between commutator bars If commutator surface cannot be repaired in this manner replace armature assembly Do not turn commutator in a lathe e Worn commutator Replace armature assembly if commutator OD is less than 35 mm 1 378 in or if undercut depth at any point is less than 0 2 mm 0 008 in Do not undercut insulation 10 Drive shaft 15 for the following Replace drive shaft if damaged e Scored or damaged shaft where it turns in bushing 6 e Internal gear with teeth broken or showing eviden
22. llows IMPORTANT e If center support bearing 10 is being replaced install on drive shaft 15 as specified in REPAIR PROCEDURES step 2 before proceeding with assembly INSTALL OR CONNECT 1 Drive shaft support 17 to drive shaft 15 seating bearing 10 in support 2 Clutch drive assembly 2 to drive shaft 15 3 New pinion stop 12 onto drive shaft 15 end with recess for stop rings 35 up e Install stop rings 35 in groove in drive shaft 15 e Pickup and support assembly under pinion stop 12 A metal block with a U shaped cutout that will slide over shaft between pinion gear and stop can be clamped in a vise to provide support see Figure 15 e Make sure stop rings 35 in drive shaft groove are fully seated in pinion stop recess and stake upper edge of pinion stop 12 over stop ring 35 at four places equally spaced Do not allow staked metal to contact drive shaft 15 ASSEMBLY OF GEAR REDUCTION AND DRIVE GROUP Figure 9 IMPORTANT e If D E bushing 6 and plug 34 are being replaced install in drive housing 18 as specified in REPAIR PROCEDURES step 3 before proceeding withassembly 28 MT STARTER 1 Lubricate D E housing bushing shift lever and drive shaft as described under LUBRICATION DURING ASSEMBLY INSTALL OR CONNECT 2 Arms on shift lever 11 with shift collar on drive shaft and clutch group 3 Assembled shift lever 11 and drive shaft and clutch group C into
23. n frame and field assembly with insulated brush screws 29 S TIGHTEN e Insulated brush screws to 1 5 N m 13 Ib in UNIT ASSEMBLY Figure 7 and 18 Support gear reduction and drive group B with pinion gear end down and proceed as follows IMPORTANT e If armature bearings 8 and 9 are being replaced install on armature 13 as specified in REPAIR PROCEDURES step 1 before proceeding with assembly INSTALL OR CONNECT 1 Solenoid assembly 1 e Pivot plunger of solenoid assembly into engagement with shift lever in gear reduction and drive group e Position solenoid assembly mounting flange and install solenoid mounting screws 25 S TIGHTEN e Solenoid Screws to 2 8 N m 25 1b in 2 Frame seal 33 3 Armature assembly 13 with bearings 8 and 9 into gear reduction and drive group e Makesure gear teeth are aligned then seat bearing 8 on armature shaft fully into housing recess 4 Frame field and brush holder group A e Place dowel Pin 28 in hole in armature support bracket of gear reduction and drive group e Position frame field and brush holder group over armature assembly 13 align hole for dowel pin 28 and marks made prior to disassembly and seat in gear reduction and drive group e Twist brush springs 7 Figure 8 away from brushes 4 and 5 Figure 8 slide brushes in to contact commutator on armature 13 andrelease brush springs to contact ends of brushes 5
24. nd Drive Group PAGE 12 1 128 4 96 28 MT STARTER DRIVE SHAFT AND CLUTCH GROUP Figures 10 AND 11 Disassembly of the drive shaft and clutch group is not required unless it is necessary to clean inspect or replace one or more parts of the group separately Then proceed as follows REMOVE OR DISCONNECT 1 Stop rings 35 and pinion stop 12 e Position drive shaft and clutch group on work 22 MM bench with internal gear end down 0 87 IN DIA e Using open tube slightly larger than shaft see Figure 11 drive pinion stop 12 toward clutch drive assembly 2 until it clears stop rings 35 e Using care not to scratch drive shaft 15 pry stop rings out of shaft groove and slide off end of shaft e Inspect edges of shaft groove for burrs that may have been formed through repeated cranking cycles Such burrs may make removal of pinion stop and clutch drive assembly 2 difficult If burrs are found use a suitable file to carefully remove burrs only not base metal Thoroughly clean away metal filings 5 e Slide pinion stop 12 off drive shaft 15 Discard 4 PINION STOP 12 old pinion stop 12 and stop rings 35 New parts must be used at assembly 2 Clutch drive assembly 2 from drive shaft 15 28 5118 3 Drive shaft support 17 from drive shaft 15 e Do not remove bearing 10 from drive shaft 15 Figure 11 Removing Pinion Stop unless replacement is required refer to CLEANING INSPECTION AN
25. nd long operating life The drive shaft is supported by a ball bearing at the gear reduction end and by a sleeve bushing at the drive end An external helical spline on the drive shaft turns the pinion as it moves into engagement with the engine flywheel An internal gear at the gear reduction end of the drive shaft is driven by the armature shaft gear at a speed of one drive shaft revolution for each 3 875 revolutions of the armature The 28 MT armature is dynamically balanced and rides in sealed ball bearings at each end Steel banding and varnish impregnation are used for added armature strength The molded bar commutator receives electrical power through radially positioned one piece brushes Constant pressure brush springs are used for even brush wear and long brush life 28 MT STARTER OPERATING PRINCIPLES Figures 2 3 and 4 Figure 3 shows an electrical schematic for the starter when it is at rest and when it is cranking the engine The starter is at rest when the engine is off and also when the engine is running normally after starting When the start switch is closed a small current flows through the solenoid pull in coil field coil and armature windings to ground A small current also flows through the hold in coil to ground With both solenoid coils energized the plunger is pulled magnetically into the solenoid This action moves the shift lever and engages the pinion with the engine ring gear and moves the contact di
26. nsulation between commutator bars d Broken brush spring s or worn brushes a Frozen bearing or other damage to drive train b Direct ground in terminals or fields a Excessive friction in bearing s or gear reduction unit bent armature shaft or loose pole shoe bent drive shaft b Shorted armature c Grounded armature or fields a High internal electrical resistance caused by poor connections defective leads or dirty commutator b Causes listed under Failure to Operate with no current a Shorted fields 1 128 4 96 PAGE 7 CORRECTION a Recheck battery switches and wiring including battery cable loss check if starter operation on engine is Slow or sluggish a Test and if necessary replace solenoid assembly a Inspect and test solenoid assembly b Inspect and test frame and field assembly c Inspect armature d Inspect brushes and brush springs a Inspect bearings armature drive shaft and related drive parts b Inspect and test frame and field assembly solenoid assembly armature and brush installations for shorts a Inspect bearing armature drive shaft and gear reduction gears b Inspect and test armature c Inspect and test frame and field coil assembly and armature a Inspect internal wiring electrical connections and armature commutator b Corrections listed under Failure to operate with no current a Inspect and test field and frame assembly
27. sc to close the solenoid switch contacts When the switch contacts close a large current flows through the field coils and armature causing the armature to turn and crank the engine This large current heats up the current carrying conductors in the motor NOTICE To avoid damage to the motor due to overheating do not crank the engine continuously for more than 30 seconds at a time If the engine has not started within 30 seconds allow the starter to cool for at least 2 minutes before trying again START SWITCH SOLENOID PLUNGER SOLENOID HOLD IN SOLENOID SWITCH ENGINE FLYWHEEL CLUTCH DRIVE ASSEMBLY ARMATURE AT REST 1M 128 4 96 PAGE 3 When the engine starts and picks up speed the overrunning clutch allows the pinion to spin freely on the starter drive shaft preventing the engine from driving the starter When the start switch is released current momentarily flows from the solenoid contacts through the pull in coil and hold in coil to ground The current flow through the pull in coil is in the opposite direction to that in the hold in coil This creates opposing magnetic fields that cancel each other out With the magnetic pull of the solenoid cancelled the plunger is released and the plunger spring pushes it out of the solenoid opening the solenoid contacts The shift lever pulls the pinion out of engagement with the flywheel Figure 4 shows a typical wiring circuit with the starter installed on the vehicl
28. tch immediately An open circuit is indicated Discontinue test and refer to Table 1 Troubleshooting e If there is current flow and starter operates release switch and proceed with the next step of the no load test 2 Close switch and observe voltmeter Adjust carbon pile load to obtain 10 volt reading 20 volts on 24 volt Starter Observe and record ammeter and RPM readings Release switch 28 MT STARTER 3 Compare ammeter and RPM readings to those listed under Specifications at the end of this manual If the readings are outside the limits shown refer to Table 1 to determine the most likely causes If the readings are within the limits the starter is operating normally TROUBLESHOOTING If results of the no load test are outside limits refer to Table 1 Troubleshooting for probable cause and correction The conditions listed in the table apply specifically to the no load test and do not necessarily apply to operation under other circumstances 28 MT STARTER CONDITION Normal current and speed Current flow with test circuit switch open Failure to operate with very low or no current Failure to operate with high current Low speed with high current Low speed with normal or low current High speed with high current Table 1 Troubleshooting PROBABLE CAUSE a Starter OK a Solenoid switch contacts stuck closed a Open solenoid winding b Open field circuit c Open armature coil s or high i
29. tool Figure 14 With drive shaft in suitable support fixture place tool bolt ends through access holes in wide end of drive shaft and squarely press bearing off of surface on center shaft 3 If necessary replace bushing 6 Figure 6 in drive housing 18 as follows e C E and or D E bearings 8 and or 9 from shaft of armature 13 using suitable bearing puller INSTALL OR CONNECT NewC E and or D E bearings 8 and or 9 to armature assembly 13 using tube that bears on bearing inner race only Press on bearing until inner race bottoms out against shoulder on armature shaft 2 If necessary replace center support bearing 10 Figure 6 on drive shaft 15 as follows NOTICE Ball bearings which are removed from drive shaft must be replaced with new bearings Removal procedure causes internal damage to bearings VIEW FLAT SIDE VIEW 32 MM 1 26 IN DIA CIRCLE _ 120 MATERIALS NEEDED PIECE OF FLAT METAL STOCK ABOUT 5MM OR 3 16 IN THICK AND 55 MM OR 2 1 4 IN SQUARE OR ROUND e THREE 6 MM OR 3 16 IN BOLTS OF EQUAL LENGTH LONG ENOUGH TO EXTEND AT LEAST 35 MM 1 3 8 IN BELOW THE FLAT STOCK WHEN INSTALLED THROUGH IT TO USE NUTS INSTEAD OF TAPPED HOLES USE LONGER BOLTS TO COMPENSATE FOR NUT THICKNESS 1 LOCATE THREE HOLES EQUALLY AROUND A 32 MM 1 26 IN CIRCLE ON FLAT STOCK DRILL AND TAP HOLES AS NEEDED TO MATCH BOLT THREADS 2 INSTALL BOLTS IN FLAT STOCK AND TIGHTEN END
30. up A dowel pin 28 and frame seal 33 e Armature assembly 13 may come off with frame field and brush holder group A or may be retained by gear reduction and drive group B 6 Armature assembly 13 with bearings 8 and 9 e Do not remove bearings from armature assembly unless replacement is required refer to CLEANING INSPECTION AND REPAIR Solenoid screws 25 Solenoid assembly 1 e Pivot inside end of solenoid assembly 1 out of engagement with shift lever in gear reduction and drive group B and withdraw solenoid assembly x 28 MT STARTER 11 12 13 15 16 17 18 19 20 CLUTCH DRIVE ASSEMBLY BRUSH HOLDER ASSEMBLY BRUSH GROUNDED BRUSH INSULATED D E HOUSING BUSHING BRUSH SPRING D E ARMATURE BEARING C E ARMATURE BEARING CENTER SUPPORT BEARING SHIFT LEVER PINION STOP ARMATURE C E FRAME DRIVE SHAFT ARMATURE SUPPORT BRACKET DRIVE SHAFT SUPPORT DRIVE HOUSING FRAME amp FIELD ASSEMBLY C E FRAME O RING SOLENOID ASSEMBLY PAGE 9 IM 128 4 96 SHIFT LEVER SCREW SHIFT LEVER WASHER SHIFT LEVER NUT SOLENOID SCREW PLATE IF USED DRIVE HOUSING PLUG DOWEL PIN INSULATED BRUSH SCREW WASHER FIBER WASHER THIN ONE OR TWO MAY BE USED WASHER THICK FRAME SEAL BUSHING PLUG IF USED STOP RING DRIVE HOUSING BOLT LONG DRIVE HOUSING BOLT SHORTER ON SOME MODELS GROUNDED BRUSH SCREW THRU BOLT BRUSH PLATE
Download Pdf Manuals
Related Search