This rebuild deals with one of the most common forms of failure of the Valeo electric starter, namely separation of one or more of the motor magnets from the motor housing. When this occurs, the magnet attaches itself to the armature making it impossible for the starter motor to rotate. There are four magnets within the motor housing. Each magnet is held in place within the motor housing with an adhesive. The symptoms during starter engagement are: the faint sound of the solenoid engaging, instrument lights going from full bright to dim and when measured, the voltage across a healthy battery dropping to approximately 8.5 volts, indicating a high current draw due to the stalled electric starter.
Although a rebuild kit and other parts are available, individual parts within the motor housing and planetary gear housing are not available separately from BMW. These latter two units are sold as an assembly. Separate Valeo parts are available from Tiedemann Auto Elektrik in Germany. You can also get complete Valeo starter motors and individual parts from EuroMotoElectrics
Following the directions in the BMW factory shop manual, disassemble the Valeo electric starter completely until you are left with the starter motor body and armature assembly.
Remove the nuts and washers holding down the commutator cover.
The brush holder is made out of bakelite material that chips and cracks easily so be gentle while performing the following steps.
Lift the end of the brush spring and remove the fiber insulators and brushes. Release the brush spring gently. I find using a strong string to form a loop works well in lifting the end of the spring.
Remove the brush spring from the brush holder. The brush spring extends through the bakelite brush holder and clips itself to the motor housing. Removal of the brush spring can be tricky, so take your time.
Remove the brush holder and rubber gasket.
Some Valeo starters came with a metal cup pressed over the end of the motor bushing. This cup retains grease and keeps contaminants out. Use a small flat bladed screwdriver and carefully pry the metal cup off the bushing.
Remove the E clip at the end of the armature. Make sure that you do not stretch the E clip, if you do, get a new one at a fastener supply store. Take note of the location of washers, shims and any other parts. The solid spacer is located between the armature and the motor housing. The shims are located on the outside of the motor housing.
Drill out the two pop rivets that hold the planetary gear housing and the motor housing together. Remove the planetary gear housing. Remove the armature from the motor housing.
Wash out the planetary gears and housing with solvent to remove all traces of old grease. This is best performed while the planetary gear housing is immersed in solvent and the shaft is manually spun. Repeat until thoroughly clean, then let dry. Thoroughly grease the planetary gears and cavity within the planetary gear housing.
Clean the commutator bars on the armature using a fine Scotch-Brite pad or similar product. Wipe down the cummutator bars with contact cleaner.
In the photo above, note the remaining black strip of magnet material still attached to the motor housing. I removed all traces of the remaining magnet and adhesive from the motor housing. This required effort as the adhesive did not break down with the application of acetone or lacquer thinner. The adhesive was most probably an epoxy.
Fabricate two spacers made from plastic sheet so that they fit snugly between the magnet that is being reattached and the adjacent magnets that are in place. This will locate the magnet correctly while the clamp is applied.
Thoroughly clean the mating surface of the motor housing with emery cloth or if you have the facilities, glass bead the inside of the motor housing to create a textured finish for the adhesive to cling to. Wipe down the area with acetone or lacquer thinner to remove all traces of oils.
Thoroughly clean the mating surface of the magnet with acetone or lacquer thinner to remove all traces of oils.
I used high temperature epoxy to bond the magnet to the motor housing after the first failure. This lasted four years until the magnet separated from the motor housing again. There are other dedicated products such as Loctite 325 SpeedBonder / Loctite 707 Activator. This product is advertised to "bond magnets on motors designed for extreme environments", withstands a temperature of up to 325 degrees F and has a gap fill capability to 0.040". J-B Weld is another possibility. I can't comment on the latter two products since I haven't had the chance to test them.
Apply a thin coat of adhesive to both the mating surface of the magnet and the mating surface of the motor housing. You will want to apply enough adhesive to fill any gap between the magnet and the motor housing.
This part is tricky as the magnet tends to wander while trying to insert it into the motor housing. Install the magnet in place. Install a plastic spacer on each side of the magnet that is being reattached. Slide the magnet to the proper depth based on adjacent magnets. Apply the clamp shown below and let the adhesive cure at least 24 hours. You may temporarily remove the plastic spacers and wipe off any excess adhesive from around the magnet edges. Replace the plastic spacers until the adhesive has cured.
If all four magnets have separated, you will have to determine which magnet went where. You cannot bond the magnets in a random order.
Reassemble the motor in the reverse order using new pop rivets. Sparingly lubricate the bushings with grease.
Purchase a used Valeo electric starter off of a Saturn vehicle. The motor housings are identical. Except for the parts under the commutator cover, the other parts are not usable without modifications.
Order a new Valeo electric starter from Ace Houston Warehouse. Contact Bob Spencer at 1-800-392-3332. Part number D6RA 15 now lists as 432586. Price in August of 2001: $172.50 plus shipping. I ordered one of these units as a spare. It appears new, but it failed to carry the usual Valeo aluminum foil sticker. EuroMotoElectrics also carries Valeo starters.