Bosch Starter Motor

Bosch Starter Motor with the Yoke body now removed ,exposing the Armature, in the background is the Brush Holder Assembly, and in the foreground the Solenoid Assembly

Bosch Starter Motor

Bosch Starter Motor, here I have removed the Brush Holding Assembly, Note: two brushes are in the assembly the other two are in the Yoke and Field Coil Assembly, if the lenth of the brushes are worn below 7/16" then fit new ones, also make sure that the brush springs still have some pressure on the bushed

End cover

here is the end cover with the bush cap sitting inside, you can see the Bronze bush inside the end cover, this needs to be re-oiled and if worn replaced,
Note: never ream out new bushes, as it will impair the porosity of the bush, and the bush will fail on you Early, they should be soaked in oil for 24 hrs, but I balance one end of the bush on my thumb print, then fill up the bush with oil, then press my forefinger on top pushing the oil out the sides, I do this about 3 times ,as its a lot quicker this way, check the other bush as well, if worn replace, or just re -oil it up

Drive End Assembly

at the drive end, you can see the Pinion engaging lever set up, see how it fits into the grove of the Overrunning clutch, the forked shape lever is engaged by the Solenoid plunger, when cleaning parts, never wash the overrunning clutch in solvents as you will dry out the lubricants and cause early failure

Armature removed

here you can see the armature along side the Yoke Assembly housing the field coils, and the Pinion engaging lever ,as well as the Running Clutch on the armature shaft, the drive pinion you can see here has 9 teeth and as , the flywheel has 137 teeth ,this then gives you a ratio of 15.2 to 1, the Starter Motor has 1.2 HP, so much for the technical talk,
this sure needs a good clean up, Note : never wash the running clutch with solvents, it will fail on you if you do, they are specially lubricated at the factory,also dont remove the field coils, unless they are unserviceable after testing, and the pole shes must be be replaced in the same position, outher wise you could get the armature poling out when reassembled

Pulled apart

Bosch Starter Motor, here is the Yoke Assembly, the Solenoid assembly, and housing, also the armature with the running clutch and drive pinion still on the Armature, all need a good clean up, as you can also see the bronze bush in the drive end housing bracket is greatly exposed to all the dust elements and that bush gets dried out quicker than the other end as it has a bearing cap to cover it

Parts of the Starter Motor

The Starter Motor parts are laid out here after a good clean up, check the surface of the commutator it should be free from pitting-and burning, clean with with a petrol moistened rag and Polish with fine sand paper, remove any rubish with a tooth pick in the slots, take care and don't damage the mica insulator

Parts from the Bosch Starter Motor

a closer inspection of some of the parts ,showing the Drive End housing body, Solenoid Assembly, Pinion Engaging Lever, the Brush Holder Assembly and the Armature with the Running Clutch and Pinion Drive still on the shaft, you can also see a Rubber grommet thingy here, in the bottom left corner, its to keep the dust out from entering the Yoke assembly, dont forget to put back in when reassembling

Rubber Gromet thingy

Bosch Starter Motor, this is the drive end, here is were the solenoid fitted Note: you can see a small rubber grommet, this helps to seal out the dust etc and keeps the solenoid plunger free of rubish

Solenoid location

a closer look at were the Solenoid is bolted onto the housing body,also the rubber grommet in place

Armature in place

Armature, cleaned up, also re-oiled the bronze bush, inside the drive end assembly housing, don't forget to slip the thrust collar on the armature shaft an then the circlip, note the rubber grommet is back in place,
Note:the bronze bush,(Bronze, so its to impregnated bush with oil, let soak in oil for 24hrs, or heat the oil up,100c, and soak for only to 2 hrs, a quicker way is to balance the bush on your thumb print then fill bush with oil, then press thumb and forefinger together, so that the oil is forced out the sides of the bush, I do it this way about 3 times, do the same with the bush at the other end as well, if bushes are worn, then replace them, never ream the bushes as you will destroy the porosity of the bush,
new ones only cost a few dollars, if they wear to much on one side the Armature pull to one side,( Growling out), and bind on the pole field inside the Yoke assembly , you will see telltale signs on the armature were it been binding as well, its the drive end bush that...

Armature in housing

have now slipped the Yoke assembly back onto the Drive End Housing Body, so here be careful of the carbon brushes, If these are worn down, they can be replaced ,you will need to cut the old ones off from were they have been spot welded onto the field post, leave about 3/16" tag so you can soft solder the new ones on,

Pinion lever

this is the drive end nearly fully in position, the Pinion lever is engaged into the grove of the Overrunning Clutch Assembly, as it looks right, it's now ready to be locked into place

Solenoid Plunger

Bosch Starter Motor, here the solenoid plunger has been cleaned and is now ready to be hooked onto the Pinion Engaging Lever

Solenoid in place

Solenoid now in place, as the plunger is now hooked onto the Engaging Lever,so therfore the Solenoid Housing Assembly can be screwed back into place

Brushes ready to go back

this is the other end showing the commutator and the two brushes exposed from the field windings,the other two brushes are in the Brush Holder Assembly that you can see there on the left, its now ready to be put back in place
Note: the terminal tag sticking out on the left,this connects to the Solenoid , on the opposite side were the connection is for the main battery lead that is connected to the solenoid

Fitting Brushes

Bosch Starter Motor, you can see the brush springs here that need to be put back in,then the end cover goes on followed by the three spacer washers, and the u clip, slip the two long through bolts in and tighten up evenly, next fit the fibre washer so that the Bearing cap seals onto it and the cap held in place by two screws,thats that end done

Brushes in position

Brushes are now all back into position this now leaves the commutator end cover to be put on, and the Bearing cap Note: those two long bolts,(through bolts) they hold the lot together, the two small screws hold the Bearing cap in position

Brush assembly

Brushes, here is a closer look at the brush springs holding the brushes that are now back into position

Bearing cap

End cover is now held into position with the two long through bolts, this now leaves the three spacer washers to go on then the "U "clip, followed by the fibre gasket held into place by the Bearing Cap, and finally held there by the two small screws

Spacer and "U" clip

Bosch Starter Motor, the spacer washer are on the armature shaft and the "u" retaining clip is back on holding it all together, that now leaves the Bearing Cap left as the final assembly will then be completed
Sorry the pics it a bit out of focus

Bearing Cap

Finally, the Bearing Cap is back on and held in position by the two small screws, so it now finished
a bit of technical stuff for you.
Bosch motor
Engine cranking speed is approx 120 rpm,
no load test its 7100 rpm @ 55 amps 12volts for a 186, and for a 202 its 12volts @ 65 amps,
Lucas motor
8500 rpm at 60 amps and 12volts

Bosch Starter Motor

Bosch Starter Motor, it has all been puled apart, cleaned ,and checked, so now ready for service.
NOTE: for more Technical information on this Bosch or Lucas Starter Motor, do a search in "Holdenpedia" under Starters