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Old 06-25-2015, 10:38 AM   #1
J Witt
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Default Sticky starter switch plunger

My starter switch plunger occasionally sticks and will not depress to turn on the starter. I've added a few drops of oil where it goes through the firewall and the switch housing, but wonder if I'm missing the real cause. Opinions?

John
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Old 06-25-2015, 07:51 PM   #2
Brentwood Bob
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Default Re: Sticky starter switch plunger

internals of switch are not good.
could be a deformed contact plate, or a worn nubb on the end of the starter plunger.
Might be best to consider a replacement from Bratten's
The problem you describe could lead to a stuck starter switch and an electrical fire. the light oil would help the fire get going faster.
Bob
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Old 06-26-2015, 06:28 AM   #3
a guy
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Default Re: Sticky starter switch plunger

Had same problem. Recommend replacing starter switch. Easy fix for around $20.00. Cooper plate deformed and sticking to starter contact. Good luck.
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Old 06-26-2015, 07:35 AM   #4
H. L. Chauvin
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Default Re: Sticky starter switch plunger

FWIW: Just one (1) recent past experience and problem with several newly made starter switches after ordering several starter switches from several of the best different Model A parts places.

These reproduction switches not long ago were "all" poorly manufactured by "Vintique" and all were sticking.

If you have one of these malfunctioning "Vintique" switches and one would like to "see" what is the problem:

1. First, entirely remove the starter switch, then get about an 11" square piece of cardboard and allow it to firmly rest on top of the starter and also allow it to be positioned to firmly abut the firewall.

2. Stand back and with a pencil, carefully observe the angle(s) of the starter rod that is protruding at an angle downwards from the firewall, and draw those different angles that one sees with duplicate lines on the cardboard.

3. Next, install the starter switch, stand back with a pencil and draw the angle(s) of the starter rod plunger coming out of the starter switch whereby you will see that one can observe "different" angles and that there is no "straight" rod alignment when the starter rod is screwed into and connected to the starter plunger.

4. What is happening is that the starter plunger connected from the starter switch is binding in friction on the sharp sides of the metal hole provided in the starter switch; hence, when the starter rod is depressed with one's foot, the starter plunger in the switch jams in the starter switch hole and the non-ferrous plate spring is not strong enough to force the starter rod back upwards to retract or force the starter switch plunger and rod to rebound back upwards after depressing same.

5. Fix: Dismantle the starter switch, remove and enlarge the starter switch hole where the moving plunger rod is binding and touching the sharp metal sides of the starter switch hole; or,

6. Try to find an original correctly manufactured starter switch that is still functional.

Hope this one (1) recent past experience and fix helps.
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Old 06-26-2015, 06:17 PM   #5
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Default Re: Sticky starter switch plunger

Thanks for the info. I can see where the pushrod is scraping against the switch housing, so I'll get after that tomorrow. I also trimmed off some floor insulation installed by the PO and that seems to help.
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Last edited by J Witt; 06-27-2015 at 04:43 PM.
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Old 06-26-2015, 10:48 PM   #6
Tom Wesenberg
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Default Re: Sticky starter switch plunger

A few years ago I had to install a replacement switch for my friend, and it also was hard to push for the reason Henry just mentioned. Oil helps some, but doesn't fix the real problem. I wonder if they are still the same? I asked my friend to save the old switch, but he threw it in the trash. Too bad, because it could have been easily repaired.
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Old 06-26-2015, 10:53 PM   #7
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Default Re: Sticky starter switch plunger

I have had a similar problem..

I did save the old switch, but the entire plunger was missing and so I bought the replacement...(we had installed a longer starter push shaft and insulated it with electrical tape!)

Do you suppose I could install the new plunger in the old switch?
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Old 06-27-2015, 12:16 AM   #8
H. L. Chauvin
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Default Re: Sticky starter switch plunger

Hi 55,

If I remember correctly, it was really the "stamped" metal bodies of the new switches that were incorrectly shaped thus causing rod misalignment.

The plungers, (new and old) were near the same diameter and length, and had the same threads for the starter push rod if I remember correctly.

The old former starter plungers had dense cardboard or fiber board to contact the non-ferrous plate spring; however, the new starter switch plungers have what appears to be some sort of much tougher Delrin or hard white plastic.

If I were in your shoes, I would try to use a new plunger with an old switch.

Please let us know if it works ....... this thoughtful experiment may greatly assist others with this common problem .......... that is ...... if better aligned starter switches are not available today.
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Old 06-27-2015, 02:17 PM   #9
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Default Re: Sticky starter switch plunger

I will give this a try and let you know how it goes....
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Old 06-27-2015, 06:30 PM   #10
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Default Re: Sticky starter switch plunger

So here is what I did. I took both switches apart and put the new insulator, brass contact, plunger and nylon plunger insulator into the old switch housing.

The biggest difference is just the fit of the plunger in the housing..the old one allows the plunger some freedom of movement where the new housing held it pretty tight at just one angle..

Taking the new plunger and wobbling it around to loosen the fit in the housing ought to help with it sticking, or you can swap parts as I did...

The only place that needs careful attention is where the contact bolt goes through the housing. There is potential for a nasty dead short here. The new switch had a fitted fiber washer that fit the hole nicely and should prevent any problems.

I installed a ground cutout switch so removal of the old switch was easy...if you do not have a cut-out you should disconnect the battery before removing the starter switch....
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Old 06-27-2015, 06:36 PM   #11
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Default Re: Sticky starter switch plunger

One more picture. It's not easy to see but the angle at which the plunger is set in the two housings is just a tiny bit different...
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Old 06-27-2015, 08:40 PM   #12
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Default Re: Sticky starter switch plunger

Great pix. I haven't managed to get mine off yet, maybe in a day or so. My plan, derived from looking at these picture, is to use my Dremel grinder to radius the sharp edge of the housing where the pushrod goes in. I think the difference between the old USA housing and the repop is that the pierced pushrod hole is not completely formed into a smooth tube.

I'll let you know if it's a good guess.
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Old 06-27-2015, 09:26 PM   #13
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Default Re: Sticky starter switch plunger

I agree..a minute or two with a Dremel should do it....the inside edge is pretty sharp...
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Old 07-02-2015, 05:22 PM   #14
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Default Re: Sticky starter switch plunger

OK, so I dismantled the switch. The first picture is before taking it apart and there are apparent concentric rings in the switch where it was binding in the tube hard enough to dent the plating slightly.

The second shows a close up of the formed tube with the edge radiused and the third shot is of the pieces ready to reassemble. I chucked the tube up in the lathe and polished up the sliding area, then applied a thin coat of moly paste.

I also put a little (it only takes a tiny amount) of moly paste inside the tube part of the housing.

So far so good, it is possible to have the plunger move smoothly through a range of a few degrees and the first trials have it moving smoothly to start the car. Hope this is a permanent fix for this nuisance.
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Old 09-23-2019, 10:13 PM   #15
Bill Goddard
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Default Re: Sticky starter switch plunger

One thing no one mentioned. I had a sticking problem too and I fixed it by bending the copper strip up against the plug giving it a heavy force to pull away from the starter stud. It has worked for the last 5000 some miles. Also if you remove the plunger and insulating plug, assemble the copper strip in the housing, and look down into the hole at the strip you will probably see the hole in the strip is off center. This causes the nipple on the insulating plug to jam cockeyed which requires more retracting force. I made a new plug from nylon and left off the nipple and crowned the end . Now the plunger can nest in the dimple around the little hole in the copper strip. There is no need to put a spring under the pushrod because it can't pull up on the copper strip. Bill G
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