Took a 3 hour drive to Knoxville today. I watched the volt gauge. Seemed to be irratic. Hung at 11.4. But would jump to 13.5 for a short time them back to. 11.4. G lite was not on during the drive. After a short stop the re start is when the lite stayed on. Guage still at 11.4. I gotta get home.

Auto zone has a voltage reg. Is this a typical symptom of the easy to replace VR?

I'm using the autozone vr , working ok.
You need to check the alternator, jumper wire to by pass the vr and measure voltage at the battery.
Google search for the procedure.

I had the same problem several years ago. I changed the VR but still had the voltage jumping all over the place. I had the alternator rebuilt and it solved the problem.
Dave

The schematic for the 914 charging system is below. You can easily test the alternator by pulling the VR and shorting the D+ and DF leads in the VR connector. This will force the alternator to put out maximum power. The voltage at the battery should be 14-16V. If not, the alternator may be bad or the belt is loose.

Keep in mind when doing this test that to get the alternator fully functional you may need to rev the engine to 2k or so.

I too have an autozone VR in my 914. Works great.

Had this issue once on my 1.8 bus motor and the commutator was filthy and the brushes were worn out.
I used to Bosch rebuilt altenators and found once they get to the above stage they generally need to be dismantled, cleaned and new bearing fitted anyway....cheap enough to do.
The bosch altenators are pretty robust I found most can be repaired to do another turn.

Got lucky. G lite is out. Volt gauge is at 13.2 so it is charging some. I am gonna roll an troubleshoot Sunday.

Try a load test with all high draw items on,are you testing @ the battery or volt gauge ?...they are normally low in there reading.

Brushes

My luck ran out. It seemed to me that my alternator was barely charging. It would generate about 12.3 volts. So we crossed our fingers and started home on the 180 mile trip.

After about an hour I had to turn on the headlights. My volt gauge has a digital readout, so I watched the numbers drop and then drop faster when the load increased. 11.7..... ticked down to 10.8 after another 30 minutes. Another 15 minutes I was under 10 and dropping thru the 9s quickly.

I knew there was a Cracker Barrel 5 miles away in Cookeville. As I pulled in to a parking place the lights and the car died and the meter was reading 9.25. So whatever charging it was doing in Knoxville, it stopped doing it after 1.5 hours.

Was able to get a Cookeville friend to take us on home. I came back Sunday AM with a U-Haul car hauler and got the car home for $61 rental and a 1/2 a tank of gas in my tow vehicle. But now my wife will be leery of our longer trips...

Charged the battery all day and test started it this morning. Tonight, I will verify the dead ALT with the Spoke jumper test.

Need to read up on maybe upgrading to the 100 or 150 amp ALT conversion.

What is the part number or which car model for this Autozone regulator?

If a replacement alternator has a built in regulator does this mean the vr on the relay board is removable/obsolete with this alternator fitted?

To carry out the test below, to short the named connections , does this mean insert a cable from D+ and into DF on the relay board?






[quote name='Spoke' date='Feb 3 2018, 09:46 PM' post='2574758']

[/quote]



The schematic for the 914 charging system is below. You can easily test the alternator by pulling the VR and shorting the D+ and DF leads in the VR connector. This will force the alternator to put out maximum power. The voltage at the battery should be 14-16V. If not, the alternator may be bad or the belt is loose.

Keep in mind when doing this test that to get the alternator fully functional you may need to rev the engine to 2k or so.

I too have an autozone VR in my 914. Works great.
[/quote]

It looks different than the OEM one. But several people said it has worked well for them.

Click to view attachment

Yes, If using an ALT with an internal VR, I would say that the VR on the board can be removed. I would wonder if wiring needs to be changed in some way tho. Maybe just connect DF and D+ like in the test below...

To test, I am supposed to remove the VR and use an alligator clip on D+ wired to the 2nd clip and placed on DF. These should be the female connectors that the VR plugs into on the board.

This will take the "regulating" function of the regulator out of the picture. And a good operating ALT should spin up a full voltage to the battery. VOM on + and - of the battery reading >16 volts would tell me that the ALT is good.

Click to view attachment

Thanks for the simple answer, just what I needed.

Test results.:

EDIT>>>> ALT belt is installed and properly tensioned.

VR pulled out
Jumper in place of VR
VOM on the battery 12.67v
Key on
G Lite on
Car starts
A few engine revs
G Lite still on
VOM = 12.13 idle and 3000 rpm
Headlights, fresh air fan, hazzards,wipers all on
VOM = 11.7 idle

Bad ALT, right?

I would say yes. Too bad, cause they aren’t fun to replace. Not horrible, but the tins make it harder than with most cars.

In your test the only item in the charging system is the alternator. I assume you've checked the belt to make sure it's tight. Also sounds like you revved the engine a couple of times to get the alternator started.

I have had this alternator off 2 times in the last 40k miles. I will not be rebuilding it. I will probably take it apart and see if there is anything obvious. Last time the pulley and shaft were moving in and out. Cause alot of clanking. The rebuilder did that repair for free and said he would not rebuild it again.

You are correct tho. It is one GIANT PITA. Having a 75 requires me to remove the exhaust on that side. Otherwise the unit will not come out. I can loosen it, but it won't come out.

Hence my thoughts of a new style Higher Amp upgrade. So I hope to get more miles out of a good high quality, high tech ALT.

Belt seems tight. I would guess 1/2 to 1" flex.

Spoke, BTW I got your relay today. Installed it and it WORKS LIKE DESIGNED. Thanks. Did you say you could modify the Werhle brand that won't blink with low load?

I haven't done it but it should be possible. Most flashers are designed to sense the bulb current with a resistor. This is why they hyperflash when the current is lower when one bulb is out. LED-compatible flashers have this same resistor either shorted out or much higher resistance to sense really low currents. With the low cost of EP26 ($12-$16) not sure if it's worth digging into the Werhle flasher.

Beware conducting this test. I took 45 - 60 seconds before fire started in the alternator wiring loom.

My readings were as follows


Idle without any drain
Rev 2000 18.2v
Idle 16.7 v

Lights on
idle 14.58v
rev 2000 17.5v

Brake light on with lights
Idle 14.09v
rev 2000 16.9v

Excellent point. This "Full on" alternator test should not be done for a long period. The goal is to see the alternator give full voltage when the VR is shorted. Once a healthy voltage is observed, the test can be concluded.

I am going with this suggestion.....KINDA. I have slowly been working on the car. ALT is out and now it has been taken apart. Brushes actually look good.

Click to view attachment

BUT they have not been aligned properly. Not really sure how the rebuilder would be able to check that either. You can see that one was hanging over the gap. So when that happens the part that is hanging over is not wearing away properly.

Not sure if it touching the 2nd contact point makes a difference, or if the unworn portion was long enough to touch the shaft makes a difference.

Click to view attachment

The video does not really show the bent-ness of the shaft. Maybe it is more visible close to the end of the 30 second video. Between the bent shaft and the mis-aligned brushes the ALT failed after 14 months, maybe 8000 miles..... THE END.


https://www.youtube.com/watch?v=36LT9MxDPAA

When buying a rebuilt alternator be sure that the lug doesn't short circuit to the case. Here is an excellent article that includes this. In some rebuilt alternator the positive lug is too long and when the cover is put on it touches.

See this:
http://www.914world.com/bbs2/index.php?sho...c=78981&hl=

Its all to common to have the builder use the longer terminal. Youll want to take in the metal back to have them see why it cant ne longer.

And ny the way i have new harnesses with all the clips and new rubber boot in stock at $88 if you fry one.

About the shaft wobble, to check it you would have to support both front and rear bearings then check for rotation variation. If just supported by the front bearing, you may just be seeing the play in the bearing as you rotate.

The misalignment for sure is an issue. It may have been that the one brush was slightly touching the other ring and causing the brush to touch both rings thus killing the armature current and causing the alternator to not produce voltage.

You could try to adjust the alignment of the brushes and have the alternator tested at Autozone or other FLAPS. Seeing how you've got 14 months on it the rest of the alternator it might still be ok.

at this point I think I am putting this one in a box and sticking it under the house. It has been rebuilt 3 times since 2013.

I have another one that was rebuilt at the same time this one was. And I found another rusty one in the garage today.

I have been spending time online trying to find a 79 bus ALT. AL108X is 70amps. They were only used on certain campers with a gas heater and a couple fans, so they are not easy to find. During that research, I read where Ratwell says an original ALT should go for 200k and a decent rebuild should make it 100k.

I was on The Samba today and the Bay Bus guys have some good threads on that subject. Lots of pictures of burnt up stuff. Make sure to use the little wedge pieces in the edge, and a gasket of some sort between the ALT and the back plate.

Help me out here. 2 issues. How do I adjust the brushes to run in the center of each copper piece.

And 2: how do I retract the brushes while I insert the rotor?

Adjust the brushes by moving the entire plate the brushes are on. I see the ends of at least 2 screws, maybe 3. Remove the screws and see if you can insert a couple of small washers under the plate and replace the plate.

I added washers once on a motor on my furnace when the capacitor-start contacts were not closing when the motor would stop thus the motor wouldn't start. The washers moved the plate closer to the armature.

For retracting the brushes, use a small wire placed through the rear of the alternator to depress the brushes while you lower the armature into the case. Then pull the wire out when installed.

Washers! Of course. How would a rebuilder see or know the brushes were not aligned? None of that is visable when assembled.