Dadgummit -- my alternator light is acting weird

I'll go try to find out what alternator I have. JPS paperwork says: "Bosch 55 amp"

Check your ground connections.

What ground connections?  There are lots of these.

And FWIW poking around the web, looks like this is a Bosch AL82N.  Can't find a single thing that says about replacing just the voltage regulator.  Anybody here know the exact skinny on this one, sure would appreciate the news.

I bought a new regulator for my Bosch alternator, but that wasn't the issue and I ended up replacing the alternator.  I gave it to Carey.  If he still has it, it's probably gathering dust in his shop.  You might want to contact him.

And my curiosity is killing me about the cover where the D+ wire is hooked on.  Two screws holding it down.  What's under there? I'm dyin' to peek . . .

The Bosch AL82N has an internal regulator.  That plastic rectangle with 2 screws is it on top of alternator.  It is replaceable for under $30.   Replacement Voltage Regulator for the German production alternators is p/n 0 192 052 007 and p/n 9 190 087 003 for the Brazilian produced units. They are not interchangeable.   Fortunately they can be replaced with the alternator installed with just a little interference with the field brush wiring.

Brazilian one shown (first link has it for $17.71) -

http://www.oscaroparts.com/bos...87-003-935156-4884-p

http://www2.cip1.com/ProductDe...BOS-9-190-087-003-US

Have you been watching too many John Wayne movies lately????

Mine was Brazilian
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Well that's a lot of good poop.  But of course you have only teased me. How do I tell which I have compare to your pictures, I guess.  Will it say Brazil??  I'll dive in and see what I can see.  Meanwhile, do you experts agree with my diagnosis: if D+ runs up to 15.5 v qith engine speed then regulator is not regulating?

Wolfy:  You Da Man!!!  Thanks.  I browsed all over the place and could not come up with anything for just the regulator.  Well done!!

If you put a volt meter on the battery terminal - at low idle (>1k) it will read 12.12.5v - pump speed up to 2-2.5k and you should see 14.2-14.5v.  This will tell you if the charging circuit is functioning.  Not sure how the blue dash light out and then just glowing come into play - perhaps corroded/dirty/loose connections to light or the alt/battery connections?

Is there an Arlington Armature place near you - there 2 or 3 in No VA area.  They are experts and can test, rebuild and supply parts. Less than a mile from my old house and also in Lorton, VA

Arlington Armature 7719 Fullerton Road Springfield, VA 22153. Phone: 703-912-7770.

I had the same problem and it was the ground from the battery to chassis. Tightend it up and no more light. I hope yours is this simple of a fix.

Will check all of that. Will let you know what I find.

OK, back from under the car.  All ground connects look good. Disassembled, cleaned and reassembled the chassis to trans connection.  It was a little corroded, and I think It was applied after paint had been put on.  I also fabricated a nice fat double aught copper cable that I added from the chassis to the trans.  Was pretty simple and now have belts, snaps and suspenders wrt chassis ground. Anyway, while disconnected, I checked the chassis to trans resistance without the wires, and it is a dead short, as it should be.  There are multiple paths for electricity to get from battery negative to the engine case and all things attached thereto. Should have lots of current carrying capability there.

So back to the alternator.  I lifted the little black cover thing, and all you get with that is two brushes. There is NO POSSIBLE WAY to access the voltage regulator from this hatch.  None.  I did notice that the push-on connectors from this brush holder to the VR were very loose.  One came off while just wiggling the thing out of the hole.  So I tightened those up, and replaced.  At idle the B+ and D+ both run about 12.4 v +/-.  Under this condition, both sides of the dash light filament are ~ same voltage and so the light does not come on.  With key turned but engine off, the light lights up bright since it has what I will call -12.x v across it.  When engine reved, the B+ goes to about 13.5 v and D+ goes to 15.7 v.  I assume that B+ voltage would then be seen by everything in the car, including one side of the dash light filament.  The other side of said filament is D+, and that is 15.7, so now the lamp sees +2.2 v, more or less, and so glows dimly.  And that ladies and germs is my story.  End of story as far as I am concerned.  Next option is to do an R&R of the alternator complete.  Not going to try to disassemble the one I have and see about replacement of the VR.  Drake suggests I go to 90 amps vs 55 amps currently.  Any cogent remarks about that?  And as to the potential alternator R&R, any tricks involved with that?  Seems I'll need a couple of big wrenches to get the fan off and back on again, properly torqued.  Other than that, what should I look out for?  And of course, what if I just go merrily along?  Am I going to burn out/blow out something by and by?  If anybody here w same basic arrangement can measure their D+ at 3,000 RPM, pls do so and say what you get.

More perusing the web, and I find out that this is the deal: need to take the cover off to get there.

I hope you asked Carey about my regulator before ordering a new one.  Mine is brand new and probably gathering dust on his shelf. Yours for the price of shipping.

Tom, I have not ordered anything yet.  You say regulator, do you mean alternator??  Regulators are less that $20.  And of course I do not yet know exactly which  VR I'd need -- apparently there as many as three different ones for this model number, none interchangeable.  There are no markings on the outside of the alt I have, so can't say who made it, where from, etc.  New ones are $200+ I think.  Likely go that route.

 

PS: VW guys say getting the fan off is a mean beeatch.  Best done with impact tools, which I do not have.

Regulator. Understood. I replaced my alternator, as well.


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OK, what would you buy: a Genuine Bosch unit (likely around 50 amps, maybe less, does not say) or the 90 amp Compu-Fire version?  And if anybody knows the trick about R&R the fan, pls pump me up about that one.

OK, all you vest-pocket experts, I'm standing by . . .

Tom, do you know what brand of alternator and amperage??

It was the Compufire. It had more amperage, but I don't remember :-/
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I'm really not thinking I have to drop the engine to do this R&R.  But I do see as how the stand might need to be undone in order to get the whole thing out the back.  One VW video shows the guy undoing the fan from the shaft from the back, so that the fan stays in the shroud.  Which is a lot of blind assembly when it all goes back, to say nothing about the lack of room in a Speedy.  Would be duck soup in a Spyder, or the Hoopty, but not so here. So the basic deal is, remove the carb linkage, and undo the gen stand, and the shroud mounting plate, then you get the thing out in your hand.  That about it??

The thermostat and attached cooling flippers and springs too if you are trying to lift/pull shroud

If you can drop the engine easily I would recommend that. Unless you have done this several times and are well acquainted with the process it is a real MF.

John Steele didn't have a thermostat and flaps put in the 36 hp shroud, and you're right Kelly-- don't try to take the fan off first. You're also right-- doing this without air-tools just makes it harder than it needs to be.

You are, however, going to need to pull the alternator stand studs. Double nut them, or grab them with vice-grips-- but you have no hope of doing this with the engine in the car unless you pull those studs.

When you do, you'll have to slide the stand and the alternator back towards the crank-pulley. When you do, you'll likely rip the stand gasket and probably bend up the little oil baffle as well. I'd tell you to loosen the shroud, but I'll bet a donut there's nothing but the fan backing plate holding it on. Once you loosen bolts, I'll bet it gets pretty floppy.

You'll need to put bolts back in where you took the studs out, and you'll likely struggle to find the appropriate bolts (the heads on the ones at the HW store will likely be too big to get a socket on). Time-serts would be nice, but you can't have everything you want. Reuse the wavy washers. You'll be stunned how hard changing an alternator can be. It shouldn't be that hard, but it is. You can do it, but block out some time, and be ready to run for gaskets and what-not.

Forewarned is forearmed.

Stan, I'll see your donut, and raise you a whole wheat bagle....toasted.

ARRRGHHH!!!! This is WAY more bull-dookey than I might have imagined.  That said, I have been trained in engine R&R, as did it numerous times on my old '61 S90.  Got so i could do it in about 15 mins by myself. I even still have the pilot tool for lining up the clutch plate, which was what all that R&R on the '61 was all about.  Anywho, I'd still rather NOT have to go through all of that now.

I'm still not getting the full picture here about what all is required to get this MF out and in again with engine in the car.  Please understand that going in I know nothing.  So far, from what I think has been said, the alt stand is the key aggravation, as I guess it is positioned with use of pins, which means that when the obvious bolts are removed, it will not simply slide aft, rather will need to be lifted a bit to clear the pins.  Hence the need to lift the doghouse shroud at least that amount.  With the engine dropped, ,the fan is right there in front of you and can be removed (best done with impact wrench) allowing the alt to be extracted without moving the stand.  Am I getting the gist of it?  What a PITA.

I'll do more research and spend time with the you-tube videos, try to learn more.

There is a question hanging out there: if I just go merrily along and let the alt light glow dimly, ,what bad is going to happen?  What is the upper limit for + voltage at D+?

And I guess it's apparent, I have no idea yet about the diabolical studs/pins yet.  What they are, where they are, and how you get to them.  Need more data -- maybe my Haynes VW book will help.  Where is Dr. Clock when you need him?? . . .

Haynes book not much help here, but I do see the error of my ways: the stand is not held on by bolts, as any reasonable man might expect, but by the aforementioned studs.  So the stand comes off by liting over these studs once the nuts are off. Stupid me . . .  Haynes suggests that the whole alt/gen assembly, once detached from the stand,  can be extracted/lifted from the shroud and stand in one piece.  All I see/hear here suggests that this is not possible as there is too much interference between fan and housing to allow a lift and pull.  Stupid, stupid stupid.  So now I understand the admonition to consider cutting slits in the stud tops so they can be unscrewed.  I wonder if that might actually work; or double nutting (need thin nuts to manage that) to back them out. Groan . . .

And all the VW videos show a guy reaching between the raised engine hatch and the body to access the fan and the nut that holds it to the shaft, easy as you please.  Puts his big ass socket and handle on that puppy and turns it loose simple as that.  Such does not appear to be an option with engine tucked into a Speedster rear end. Still not getting a good picture of the sequence needed to get this job done -- just visions of "well shyt!!" at just about every turn.

And as long as we are discussing auto mechanicing theory here, lets suppose one was able to get those four studs out and the stand+alt removed, etc.  Upon reassembly, why not use bolts vs studs??  Can anybody give me that answer??

OK, so Stan said as much about the bolts, and yes, I am stunned at the level of complexity here for what should be an easy job.  Seriously thinking about not actually doing this.

In a Beck there is ample room to get to that big nut holding the fan to the alternator shaft - no so with other makes that have the fake fire wall close by.  It might be possible but getting it back on tight is critical as a loose nut will wallow out the hole in fan.

Looks like you could remove the fan belt, the fan pulley,then the face of alternator (3 screws), and finally the bearing holder?  I thought regulator was on top - appears that the brushes. Details below -

http://www.thesamba.com/vw/for...t=alternator+rebuild

Wolfgang: look at the picture I posted above -- the VR is tucked into the other end (fan side) of the case. Can't get there from the pulley side.  And it appears that some versions of alternators do indeed have the VR integrated with the brush holder.  Not so on the one I have.

I've removed my alternator with the fan attached several times.  It's been a while, but I think I just had to loosen the shroud so that I could move it slightly.  The pedestal did not have to be moved.  Then again, that might be easier then moving the shroud.

Ah - its on the skinny end.  So much for that 3 beer induced idea.  Just drive it and have changed cell phone should it crap out.

Lane, I like you approach.  If can leave the pedestal in place that would be MAJOR. Pls say what it took to loosen the shroud.  I have not done a full survey (will require use of a mirror), but seems like there are at least two bolts on either side, sort of facing the intake manifold easy to get to.  Would be cool if there were just those two, but I'd not expect to be that lucky.

Perusing the web a bit more.  Found out this:

To test "diode trio" for damage:

Start the engine and turn on headlights, wiper motor, flashers, etc. to create a "load". Use a digital voltmeter to compare the voltage at the D+ terminal to the voltage at the B+ terminal. The "diode trio" is bad if the voltage at the D+ terminal is not within 0.2 - 0.3 volts of the B+ terminal reading.

This is clearly not the case w my equipment, so I guess my diodes are toast.

And some words about the D+ and dash indicator bulb:

with the ignition on but engine off, the indicator light sees 12 volts from the battery (via ignition terminal #15 on the coil) and glows, but with the engine running, it sees 2 volts (14 volts minus 12 volts) running the other way, from the alternator. It doesn't glow (needing more than 2 volts to do that), but the alternator still "sees" the connection to the battery.

So -- If the Alternator is charging, the (D+) terminal has 12 volts on it; the blue wire from (D+) carries 14 volts to the "Alt" light in the instrument cluster. When the engine is running, there is 12 volts on the *other* side of the lamp from ignition terminal #15, so potential difference is only 2 volts and the bulb doesn't light. But, if the alternator dies or the drive belt breaks, there is no voltage on (D+) (looks like ground) and current flows from #15 thru the lamp to (D+), and the "Alt" lamp comes on to warn the driver of a problem

There are those two and a couple along the front of the shroud, all relatively accessible as I recall.