Here are the pictures: Wear on armature and spacer: http://penoff.com/photo_dump.html#2
Planetary gear set (in a plastic housing, I might add): http://penoff.com/photo_dump.html#3 Amazing how powerful these starters are, but also how cheaply they’re made, too. -D On Apr 16, 2023, at 3:00 PM, G Mann via Mercedes <mercedes@okiebenz.com<mailto:mercedes@okiebenz.com>> wrote: Thanks !! I have an ongoing interest in how and why things fail. Since it was identified as a "rebuilt starter" it seems likely the rebuilder failed to install the required fiber washer to keep the armature from doing exactly what that one did... perhaps.. Or, the bendix seized on the shaft and instead of traveling to engage, pushed the armature forward... ?? "If it can happen, it will, but only when you least expect it." On Sun, Apr 16, 2023 at 10:51 AM dan penoff.com<http://penoff.com> via Mercedes < mercedes@okiebenz.com<mailto:mercedes@okiebenz.com>> wrote: Because Grant put the idea in my head to do some failure analysis, I had a couple of minutes to spare so I tore into the failed starter. I’l post some pictures in a little bit, but suffice to say I was surprised! It does have a planetary gear set that’s internal, which was pretty cool. Based on what I saw, the front edge of the armature windings were rubbing against a metal spacer or cover between the armature and the planetary gears. So much wear that the varnish was worn off the windings, meaning they were shorting out. I couldn’t determine what had caused the end play in the armature to allow it to move against this plate, but it’s clear that was not a good thing. I couldn’t get the solenoid off of the main casting, as the phillips head screws they used were driven in with an impact or may have had thread locking compound on them. I’m pretty satisfied that the armature was shorting to ground, causing enough of a voltage drop that the solenoid wouldn’t pull in, letting the motor freewheel with the armature rubbing the metal plate, which was the source of the noise I was hearing. -D _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
