Replacing starter solenoid

[jacques debauche]

Our starting solenoid has occasionally been failing to complete the starter primary circuit, so rather than risk a terminal failure (no pun intended) at an inopportune moment, I had Mr. Moyer send me a replacement solenoid. $45 is cheap insurance. From years of replacing solenoids on balky Bosch automotive starters, I assumed that I could simply undo the four electrical connections and the two mounting screws and remove the solenoid from the starter. Wrong! What is the trick? Is it even possible to replace the solenoid without removing the starter from the engine?

[thatch]

Jaques D.,
Assumming that we're talking about a Delco starter here, after removing the wiring from the back end and the 2 screws from the flywheel end you have to rotate the solenoid about 30 degrees to free it up from the starter. There is usually a rubber seal between the starter and the solenoid which people sometimes add additional sealer to, making the removal process more difficult.
Tom

[jacques debauche]

Thanks Tom - tomorrow we twist.

Jacques

[jacques debauche]

Thanks Tom - the twist of the wrist did it. The whole job takes under ten minutes when you know how. However, let me warn fellow-dummies that the lthree ittle clips that keep the coil spring under compression during shipping of the new solenoid must be removed before installation. Please don't ask how I know this.

Jacques

[jacques debauche]

After replacing my starter solenoid, I did a post mortem on the old one. The solenoid had occasionally been failing to connect the primary starter circuit which suggested worn or corroded contacts. In the "before" picture you can see a ring of corrosion on the circular metal washer which is pushed up against the copper terminals to make the main starter connection. Why Delco chose to save pennies by using a plated steel washer in this application is a mystery. There are small areas of deposits on the two copper contacts as well. These deposits are just enough to occasionally prevent electrical contact.

Rejuvenation is easy. To open the contact chamber you will have to remove the two 5/16" head screws and the 9/16" hex nut on the starter connection, but not the nut to which the battery was connected. You can then lift core with its the washer and little spring from the solenoid coil. Don't bother trying to clean up the washer - just remove the D-clip and flip the washer over. Remove the deposits from the copper contacts with a file or Dremel. It should now look like the "after" picture. Reassemble, and reinstall on the starter or set aside as a spare.

[thatch]

Jaques D.,
Thank's for the solenoid replacement update. Over the years I have "cleaned up" quite a few of these Delco solenoids when a replacement wasn't available and they work, but never as good as a new one. Save 'em as spares but use a new one when you can. As an added little tidbit for those who might be interested, that little silver tab at the top of the inside part of the contact cover is the infamous "R" terminal that comes up in our wiring discussions occassionaly. As you can see from this great photo it also comes in contact with the round contact ring when the starter is engaged.
Tom