Intermittent dead starter solenoid - Any ideas?

[Greg Scallon]

Hello All,
I'm dealing with a frustrating problem and hoping the wise minds here can help me out. I have a 58 A with its original 6V electrical system. Intermittently, when I turn my key to activate the starter, I get nothing. Not even a click of the solenoid. Nothing. Then, sometimes, it'll fire right up with what seems to be fine cranking power.

I replaced the ignition switch but that didn't solve it. After that, I was sure it was the Joe Leoni hot-start relay that had gone bad, since it seemed like that was really the only other potential fault-point in the ignition/starter circuit. Unfortunately that wasn't it either. I replaced it and I'm still having the problem.

A few clues.
1. It's intermittent.
2. When the starter does fire off, it seems to crank with fine strength.
3. Battery shows 6.39v when checked across its terminals.
4. I'm getting 6.3-something volts at the #2 fuse block
5. I've cleaned and sanded my battery terminals, the 1, 2 and 3 fuse connections, the 30 terminals and wires on the headlight switch, and all the terminals and wires at the ignition switch.
4. I've cleaned and tightened all of the wires connecting to the new hot start relay and all the wires connecting to the starter itself.
5. One interesting clue is that the problem seems to be happening more frequently lately. It happened today on a drive, and today for the first time I was also noticing the engine hiccuping at over 4k rpms under load. I've also for years had issues with a white residue around my Optima battery that keeps showing up even after I clean it. The battery is on a tender much of the time.

I have two competing theories/ideas:
1. Do you think a weak and dying battery could cause these intermittent symptoms? Assuming the new ignition switch and the new hot-start relay are working correctly, could there just not be enough voltage/amperage in the #50 wire to activate the starter solenoid, therefore, no sound when I turn the key? I was thinking that might explain why the problem is happening more frequently(battery is dying), and possibly why the engine hiccups. Maybe the coil isn't getting enough juice at high rpms? Could the white powder coming from my battery when it's on the tender be an indication that the tender is killing it?
Or 2. I suppose it could be a problem with the internal contacts inside the starter solenoid. If they are sketchy somehow, maybe sometimes they just don't fire off the solenoid as they should.

If anyone has thoughts, or suggestions on what I can try next, I'd love to hear from you.

Thank you so much,
-Greg

[David Jones]

Gregg, you can replace the starter solenoid easily. They do go bad and I replaced two recently. I bought two used ones for $18 each off the samba. The vw one is identical.
https://www.thesamba.com/vw/classifieds ... ton=Search

[Phil Planck]

Could be:
Solenoid
Bad battery cable connection
Bad ground at trans

I had a 6v Optima for years and never kept it on a tender. AGM batteries will vent if overcharged. Make sure your tender is operating correctly. I have another brand AGM in my 912 and do not use a tender. Neither car driven frewuently.

[Mike Horton]

Greg, I agree with David and Phil on this one. I've even cleaned a couple of 12V Bosch solenoids to work better, in times past. If you can clean, or repair, that's good, if not, the old one is still bad. If you find a source for the 6V solenoid, please share.

2 years ago, I went through my spare 12V starter for my 912, and let me assure you, the basic Bosch motors are way overbuilt. My effort was primarily cleaning, to include the commutator segments, which were just a little dirty, and still concentric with the shaft, so I simply cleaned the copper surface in the lathe, with a 3-M Scotchbrite pad, the brushes were hardly broken in, so they too, got a scuff pad cleaning, I cleaned the solenoid, and reassembled it, tested it, and installed it, and it hasn't missed a beat since. I have a "hot start" relay to install, but use these to "unload" the current through the switch contacts, a good idea.

Joe L. ?

[Richard Holler]

I had recently thought was a starter issue ending up being a bad coil, I think it was stressing the battery so much under load. I would check to see if you are getting consistent spark. if your hiccuping at 4k, that wouldn't be a starter issue.

[David Jones]

Gregg, another solution is to buy a complete rebuilt 6 volt VW starter from your local parts store, then rob the solenoid and take the starter with old solenoid back as your core. NAPA sell a rebuilt VW starter for $45 which is a better deal than buying a rebuilt starter or even a new one for 3 times the price.
New 6 volt starter solenoids cost more than a complete 6 volt starter motor. It is a crazy world.

[Steve Douglas]

I had the same problem with my 59, it would start fine about 75% of the time and then it would be dead, usually at the worst times. The first issue was the battery voltage, if driving for an hour or so with the lights on the car wouldn't start. Cause: voltage regulator was passing only about 8-10 amps once it got warm, so after an hour with lights on, the battery was to low to pull the solenoid in. Second issue that added to the low voltage issue was the ignition switch contacts were getting burnt, so limiting the voltage to the solenoid. Third issue, the wire connections needed cleaning. Remedy, #1 - all connections were cleaned and retightened, the red wire at the battery, the wires at the fuse box, the fuses, the bullet connectors at the light switch and ignition switch, the ground straps at the battery and transmission, and the solenoid slide on connector was replaced. #2 - installed one of Joe Leoni's starter realay kits. #3 - Replaced the regulator with one that allowed 40amps. #4 - cleaned the ignition switch with De-Ox and Contact Cleaner, sprayed heavily to soak inside and then worked the switch back and forth to clean up some the contacts.
This lasted for about 10 years, before the ignition switch finally gave up, the plastic "Y" shaped contact holder broke, I had Larry Markham rebuild the switch and everything was good. In my on board spare parts I carry one of the new reproduction switches, which will get me home if the original gives up again. Rumors of the new switches not lasting very long may actually be from the other issues overloading the contacts.
Setting the voltage regulator to make 7.2-7.4 volts when running at 2500 rpms+, and slightly less (6.8v) with the lights on, and that there is adequate current (amps). I placed an ammeter in line at the BAT terminal of the regulator it measures only charging current since the regulator won't allow it flow back to the generator.

[Dave Wildrick]

3 - Replaced the regulator with one that allowed 40amps.

This is very likely to fry your generator eventually.

Joe Leoni says that you should limit the current to allow no more than 23 amps (on a 6V car). If your battery gets low on charge and you are driving at night in the rain with the lights, wipers, and radio on, the system will demand more amps, the regulator will comply, and the generator will throw solder and burn itself out trying to provide it.

My friend, Jim Learmonth, lost several generators from this effect before he discovered the cause--the original equipment on many 1965Cs cars silver small regulator that can pass 40 amps, but which has no provision to set an amp limit.

I got rid of that regulator on my 65C and replaced it with the earlier big black regulator, which is set at the 23 amp limit.

[Steve Douglas]

In looking at the big black regulators that I have, they are stamped with a current rating of 40amp or 50amp. If you calculate the load using 7 volts, w/ headlights @ 65watt each (X2), parking lights & license lights @ 5watts each (X4), Dash lights @ 1.5watts (X8), Taillights at 8 or 10 watts (X2), a 6-12 volt converter to power the radio at 2-3 amps.
Calculations; 130+20+12+20= 182 watts /7volts = 26 amps. Then add the brake lights, turn signals, wipers, and the charging of the battery and 32-35 amps could be reasonable. That is at 7 volts and if the voltage is less the amperage goes up. That is why the voltage setting at 7.2 to 7.4 is critical the difference between 200 watts @ 7 vs 7.4volts = 1.5 amps

[David Jones]

I think I posted this earlier but it may be worth reiterating. I noticed that after a drive of more than 30 minutes it took my coupe much longer to show a full charge on the battery than it did the cabrio and this with identical chargers and equivalent batteries. Upon checking the charge rate of the coupe I found there was not one only a discharge of 7 amps at 5.9 volts until I revved it up when the voltage climbed to just above battery voltage so I went for the obvious and changed the brushes. Upon re-checking I found I now had 7.3 volts at revs (2500). From now on that is going to be a maintenance item after every oil change. Check charge voltage! Buy a spare set of brushes.

[Jules Dielen]

Buy a spare set of brushes.

+1 on this. After being left stranded twice due to worn brushes I have a set on me every trip now.

[Dan Epperly]

Sounds like a bum solenoid. They do that intermittent bit and it will drive you nuts thinking it is something else.
Best way to tell is next time the starter acts up go underneath with a screw driver and bypass the solenoid by arcing the terminals (the one the battery cable goes to on the solenoid and the one that the braided cable is attached on the motor) . If the starter motor whirls it's your solenoid. if nothing happens your starter is toast.

[Dave Wildrick]

In looking at the big black regulators that I have, they are stamped with a current rating of 40amp or 50amp. If you calculate the load using 7 volts, w/ headlights @ 65watt each (X2), parking lights & license lights @ 5watts each (X4), Dash lights @ 1.5watts (X8), Taillights at 8 or 10 watts (X2), a 6-12 volt converter to power the radio at 2-3 amps.
Calculations; 130+20+12+20= 182 watts /7volts = 26 amps. Then add the brake lights, turn signals, wipers, and the charging of the battery and 32-35 amps could be reasonable. That is at 7 volts and if the voltage is less the amperage goes up. That is why the voltage setting at 7.2 to 7.4 is critical the difference between 200 watts @ 7 vs 7.4volts = 1.5 amps

Steve, I don't really have a dog in this fight, and I don't dispute your calculations.
However, I consider Joe Leoni the authority on this. Maybe the 356 generators were underpowered relative to the regulator's capacity.
But based on the prounouncement of the guru, if your battery is undercharged and you run all those power-drawing items simultaneously at night with your regulator set at 40 amps, you are tempting fate on losing a generator.
I was with Jim Learmonth when it happened to him on a trip to Prescott, AZ, running an aging 6V Optima battery at night.
You are certainly free to do as you wish. Your your mileage may vary.

[Dick Weiss]

Many-many years ago when starter solenoids were difficult to source--and I had difficulty starting my C cp cold or hot,
I removed the starter, removed the solenoid, tore it down and found that its internal shaft was worn down @ an angle which prevented its "pull-in" since the action is 'kinda' off center when activated.

Yes, here comes the "rescuer" of JB Weld, cured overnight, refinished its diameter, reassembled everything, and it worked A-OK and the car was sold to a 'Louisviller' in early 2000. Later, the solenoids became available via Stoddard.
OH, the internal contacts were dressed up easily, too.

However, a couple of years ago, a local member needed to exchange his C cp starter and a supposedly rebuild was installed, but intermittant starting problems were encountered, so it was checked out, but it still didn't work right.
The solenoid didn't have any numbers on its shell, I called the supplier, and they wouldn't exchange the solenoid, so I got a Bosch replacement and the problem was solved; BTW, the starter wouldn't work even w/a Leonie relay!

Dick

[Martin Benade]

I have occasionally seen odd intermittant problems from batteries that test as good. In particular Optimas. Can you borrow a known good battery?