Gentlemen, Start Your Starters: Starter resto and repair secrets
Most Moparphiles just slam in another one and roll. Today, the popular MP mini-starters, which usually bolt right in, are a popular fix. And, with good reason: they are light, powerful, compact, and draw less juice. Why, then, would anyone want to mess with their original starter, circa 1970 or so? Actually, there are several good reasons:
- You like the unique sound
- You have a numbers-matching concours resto
- You're cheap
- The mini-starter won't fit your particular engine / trans. / exhaust combo.
- You want to keep your Mopar all Mopar (the MP ones are of Japanese origin)
First, a little primer on Chrysler starter tech. Prior to the introduction of the subject double-gear-reduction starter in 1962, Chrysler outsourced starters, mainly to Auto-Lite. They were heavy, crude, drew a ton of current, and were none too reliable. The 1962 Chrysler design broke new ground by developing the first starter, anywhere, using a cast-aluminum housing and double gear reduction. The armature spun at much higher RPM than the norm; this feature, combined with the extra helical gearset, served to create the now-famous waaa-waaa-waaa sound that told you, from a block away, it was a Mopar cranking.
The solenoid shift assembly and contact setup were designed and built right into the starter, no more bolt-on "piggyback" solenoid. This starter was a giant techno-leap forward, and would be used in production until the late 1980s. Applications included virtually all Mopar cars and trucks, the only noteworthy exception being '66-69 4-speed Hemicars, whose giant flywheel would have reduced cranking RPM below that needed for reliable starting.
For 1970, a fairly significant redesign increased the reliability, weather sealing, and serviceability of the solenoid assembly. For 1975, a slightly larger, 1.8 HP unit (0.3 HP more than all earlier units) was introduced for hard-to-crank applications. All of these starters were of the same basic design, and service procedures are similar. For our hands-on example, we're dissecting a high-torque 1975-up unit, but, in any case, our plan is to show your only the key elements and certain tricks for quickly getting your unit functional again. A factory service manual for the year, or at least the basic variation, of the starter you are ripping into is highly recommended.
As with any good rebuild, it helps to know what you're dealing with,
and when it's time to pack up the tools and simply get a different
starter. Of course, if you need a date-coded starter for your
half-million-dollar 1971 HemiCuda ragtop, you might want to carry
things a bit farther than the rest of us.
There are three common failures that stop you - and your starter - cold. #1 on the list has to be a clutch failure. Luckily, this usually give you some warning - the starter will, occasionally at first, intermittently not "catch"; i.e., the starter will spin but the engine will not.
Second is a solenoid contact failure. This also typically gives some warning - the starter will 'click" but nothing else will happen.
Third is a lubrication failure. This usually doesn't prevent the starter from cranking the engine, but speeds will be down and noise levels way up. Unattended, the bushings will be destroyed in short order.
Other failures include brush wear, which isn't too common due to their beef, armature burnout or excessive commutator wear, solenoid coil burnout, etc. With any of these, you may be better off finding a different unit. Few parts are still available from Mopar, although the aftermarket has a ready supply. But putting $50 worth of parts into one of these would probably be a lesson in bad economics, said HemiCuda being the exception.
It's also possible to detail your starter to impress show judges, the important points to remember here are that the cast aluminum housing is natural and unpainted (clean it by blasting with plastic media or walnut shells, etc.), and the steel parts (the field shell and end cap) are semi-gloss black.
The captions, as usual, will walk you through the service details. And waaa-waaa-waaa to ya!
Chrysler - Mopar starter repair details and photos
|1. 1970-up starters (shown) are a tad more reliable -
and definitely easier to service - than earlier models. The bolt-on,
gasket-sealed solenoid assembly is one reason.
|2. Earlier models required that the solenoid housing be caulked after assembly.
|3. Exploded, you can see the basic simplicity of the design. The battery cable bolts directly to the contact stud (circled), and the moving solenoid contact completes the circuit to the field and brushes.|
|4. Disassembly begins by removing the two thru-bolts and the end shield, then simply pulling out the armature. Remember the location of all thrust washers.|
|5. Next, pull the field housing back just a tad, exposing the bolt-on field connector. Remove the bolt and then remove the field assembly, which seldom requires any servicing.|
|6. Next, unbolt the solenoid assembly by removing the nuts only. (Pre-'70 varies here and though step 9, see service manual.)|
|7. Now pull the solenoid assembly free. The 4-pronged thrust washer visible here is a key item in reassembly later, since the four tabs hold the brushes back while the armature is slipped in place. Don't lose it!|
|8. Now unbolt and remove the solenoid bolts.....|
|9 .... and the nut(s) from the small stud.
10. Now you can pull the coil and contact assemble back. Don't pull to hard, one small wire is still connected. It's soldered on the opposite side, but if you're careful, it can remain in place. If the contacts are burned or pitted, clean them up with coarse sandpaper. If the moving ring is pitted (which is quite likely), simply rotate it so fresh "meat" will be utilized. If the large contact stud (battery terminal) is really in bad shape, a replacement can be had as Mopar p/n 3579123. Reassemble the solenoid setup.
|11. Next, pop off the gear train cover. It will probably look pretty good under here. No matter, it should come apart.|
|12. Remove the two snap rings (arrows), then slide the pinion shaft forward. The clutch (drive) assemble will basically fall out.|
|13. A very cursory test fo the clutch can be done in your hands. It should spin freely in one direction, but instantly lock in the other. If the problem with your starter was intermittent starter-spins-but-engine-doesn't-crank, find a new drive unit, test results notwithstanding. Otherwise, soak it in solvent, then boil it in hot heavy oil.|
|14. Inspect the armature's commutator. There should be very low resistance from any segment to any other. If the segments are nasty looking, they could be trued in a lathe, but, for most of us, it will be sandpaper! After cleanup, try to "undercut" the insulated area between each segment a bit with a knife or even a screwdriver. High tech, this isn't.|
|15. All obvious areas should be lubed with high-temp grease before assembly. This includes gears, bushings, etc. Even this fairly low-mileage unit had a totally dry rear bushing!|
|16. Once screwed back together (see service manual if you think a screwdriver is a drink), you're ready for another 100,000 miles.|
|17. Several heat shields were used over the years. This one's from a mid-1980s B-van. If you have headers which tend to toast the starter, try to find, or fabricate, one of these.|