STARTER REBUILD FAQ rev 0.5
by Thomas Walter
3/10/95
My starter seemed to be turning over slower one morning. Not a problem with a warm engine, but after sitting out over night, it was turning the engine over very slowly. After cleaning the battery terminals, cables attaching to the starter, and checking the charging system, the problem still persisted.
Since the Sear's "48 month" battery was four years old, seemed the most likely cause. A new battery seemed to get the starter to turn a little quicker, but not that much of a difference.
Next cool morning greeted me with the slow: er, whirl, er, whirl of the starter cranking. Thankfully with the car in good tune, it would start after a few cranks of the starter. It would have not functioned for my "dead clutch" trick I've used in the past, however.
Removing the starter from the vehicle (easy on 510's, a nightmare on a Roadster). I proceeded to check the most common areas for problems.
GENERAL:
The first time you disassembly the stater, I recommend having a good shop manual and note book nearby. Making a sketch of things as they are disassembled helps when reassembling.
The solenoid is retained with either two or three screws or bolts. [Hitachi used three bolts, Mitsibushi used two large screws]. Once removed, make a note of the spring, and how the plunger is attached. Set aside.
The Plunger is pulled back by the electromagnetic force of the solenoid coil. Once it is drawn back, engaging the starter gear to the ring gear on the flywheel, it presses down on push rod. The push rod closes the contacts within the tail of the solenoid housing.
If the starter is just giving a "clunk" a quick test is to put the vehicle in neutral, parking brake pulled on! An old screw driver shorted between the battery (LARGE) lead, and the little male slip on connector should give the same effect. If that works fine, problem is either the ignition switch or wiring. Every Datsun I have owned has had poor contact problems, after many years, between the male and female connector to the starter solenoid. Light crimping the female connector, and sliding back alleviating most problems!
Back the the starter, if the starter still has a "clunk" but does not rotate, then try shorting that screw driver across the two big terminals! Sparks will fly, but the starter should respond by spinning. If so, fault lies within the solenoid. If that have any effect the fault is within the starter.
HITACHI SOLENOID INSPECTION:
The earlier Hitachi units are my favorite, as they can be disassembled. Mitsibushi used a SEALED solenoid. With a crimped seal it is not possible to disassemble, only replaced as a unit.
The Hitachi Solenoid the tail housing, is retained with two screws. Sometimes a impact screw driver is required to remove them. Once they are removed, use caution to straighted the male contact, which the plastic slides over, and remove the small ring terminal on the the 8mm stud (which also connects to the starter motor windings).
You should be able to slip back the cover, exposing the large copper contacts. There is a little spring to hold the plunger back from the contacts, note its position and function. Set aside. I have rarely seen a coil wire 'burn out' on these starters, most common problem is the contacts have become pitted with age. A quick filing with a emery board (my spouse wondering where they go!) will file off the top high spots and restore the shiny copper surface. Don't worry about small pits in the surface, as long as 90% of the surface looks good. The contact bar is also cleaned up. reinstall the spring, and reassemble.
STARTER INSPECTION:
On to the starter motor. Usually the tail cover will have two 10mm, across the flats, bolts and two screws. The bolts hold the three main sections (nose housing, center body, and end cap) together, the screws hold the brush plate in place.
The later Mitsibushi starters have a "E" ring on the back of the starter, covered by a small rubber cap. Remove the cap by prying under it and lifting. Remove the clips, and make a note of the shims.
Remove the two long bolts, and little screws, and the "E" clip if necessary.
Once removed the amount of "black crud" inside the end cap will give a fair idea of the amount of wear on the brushes. The brushes should be standing proud of their holders, with the spring applying pressure to them. Rare to find a broken "Q" spring on the older starters (newer ones use spring wire rather then the flat spring steel).
I was able to buy the set of four brushes for $4.00. I Took the old ones into a local alternator/starter rebuilding place and was able to obtain them without any fuss. The local Nissan dealer wanted $4.00 EACH for them, but does not stock ANY internal alternator or starter components. When a mechanic is charging $50/hour it is faster, and cheaper, to replace a starter as a unit. In our case, when you have a Saturday afternoon available it is much cheaper to disassemble/inspect and replace the worn parts!
REPLACING THE BRUSHES:
A parts washer to remove all the old grease, and bush material, leaving everything clean is recommended. Makes the job much easier.
Two of the brushes have insulating sleeves, used on the positive side, the other two are attached to the grounding plate. Normally the leads are 'staked' to the holder assembly, so a little careful prying will bend the holding tab back to release the pressure. To unsolder the leads requires a good size "Soldering Gun". My 100 Watt Weller works fine, with a little patience. It helps to dab a little solder on the tip, to help transfer the heat. A pair of needle nose pliers, and a little stainless steel "pick" being used to remove the old wire. Yes, it sounds like a four hand job... clamping the brush plate in a vise helps.
Once removed, clean up the solder pad area. Pay attention to which leads are insulated and which are attached to the ground (bare leads). Install the brushes. Snap the "Q" springs back over the ends.
Usually I will just clean the commutator (the portion where the brushes rub) with a 3M extra fine sanding pad (some sort of hi-tech synthetic material, works great. Do not use Steel Wool! Just rub back and forth to give the copper a shiny clean appearance.
Once this has been done, a sharp pick instrument, can be used to clean the old dirt/grease/brush material out between the copper strips. A repair manual goes into great detail on how to "undercut" the micra insulators, but usually that is not needed. [If the commutator is worn badly enough to require machining, then it is easier to replace the starter, unless you have access to a metal lathe].
OTHER TRICKS:
Between cleaning (if possible) the solenoid contacts, and replacing the brushes it will cure 90% of all starter ills. If the bushings are worn enough to allow the rotor to move closer towards the magnets, a slower starter speed will result, with an increase in current. A Bent rotor shaft, shorted or open windings, etc. may occur, but in such cases is it much simplier to just obtain a rebuilt unit!
[If you decided to overhaul a starter fitted on a large V8 motor, those bushings WILL need replacing, due the much heaver weights involved. The smaller units fitted to our Datsun's just don't have that much weight to wear as much]
The "Bendix" unit, which engages the starter gear to the ring gear, is pretty much trouble free on our small engine Datsuns. If the gear is badly worn, inspect the ring gear (on the flywheel) for damage. There is a "overrunning clutch" which allows it to spin the motor, but once the motor is running it prevents the engine from spinning the starter. Inspecting by hand usually gives a good idea of it's functioning.
Pay attention to the shims, if any, when taking everything apart. Putting them back in the same order. This will address any "clearance" problems with the rotor and housing.
REASSEMBLY:
LIGHTLY apply a little white lithium grease to the folk on the starter bendix. Replace the gaskets, and little rubber seal.
Only trick to reassembly is holding all four brushes back to slip over the end of the commutator. Usually a matter of patience, and slipping two of the bushes in place, then using a small hook tool to assist in pulling back the other two brushes.
There is a small insulating paper inside the starter tail "cap". Only electrical tape that holds up here is 3M #33 or #35 electrical tape. EXCELLENT quality stuff, but at $5/roll it will leave you gasping! Worth the price. Double check everything clears the cap.
Before installing the long bolts, look down through the starter to see the threaded holes. Helps to visually check before installing the bolts.
The small screws are easier to line up it you use a thin tool (once again my little pick) to move the plate so the screws holes line up. [Hitachi allows for play, Mitsibushi plates line up tighter on the long bolts and make reassembly a little easier]
I'll usually "bench" test a starter to confirm everything is OK. Just attach a set of Jumper cables to the stater (clamp the "-" one to the mounting ear of the stater). The "+" side to the heavy terminal. Then use the screwdriver to short between the large terminal and the solenoid contact. I usually have my foot firmly placed on the starter when I do this. You should be greeted by the sound of a nice heavy "clunk" and the starter turning over! I know of someone who "loads" the starter by jamming a 2 x 4 into the starter teeth to make sure it can rotate "under load". While that does work, I would highly recommend making a hold down fixture to hold the starter, and 2 x 4 as wood chunks tend to go flying!
[Need a good exploded drawing to go along with this description]