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Thu Jan 31, 2019 11:05 am

Is it possible you have a starter relay installed?

Thu Jan 31, 2019 11:22 am

SamboSamba22 wrote: 55 Amp Alternator Question:
On my original ‘74 alternator, I have a thick (8 gauge?) wire coming off the alternator leading to confusion on what exactly this ties into. On the schematic, I have no visual of such blue wire.
Small blue wire - indicator light
Large red wire - starter 50
Brown wire - ground
Green wire - isssss????

Trying to figure this out, something’s array as I had it hooked up previously with a running bus but resulting in ruining a voltage regulator.

Any insight is wonderfully apprciated.
Sam

-The green wire is the DF from the regulator

-There is typically a wire for the factory test plug which isn't very large, maybe a 16 gauge and is black IIRC. This wire is best left disconnected inside the cover on the alternator, bent back on itself, and held with a wire tie.

-Don't know about another large wire, but if you have such it probably isn't needed unless you have some kind of unusual electrical stuff that was added. The schematic does show another ground wire in the area, but it doesn't look like it does anything at all. Maybe it is require in certain application?

Thu May 09, 2019 7:31 pm

It has already been well documented here in this thread, but I evidently also had a short on the + side. I'm re-heatshrinking the crimp and turning the connector slightly -- I'll add a little nylon washer or so as well to insulate the metal washer...

Mon May 18, 2020 12:54 pm

I fried my alternator and have to replace it. I have a Westy camper which I read may have a 70 amp alternator rather than a 55. How can I tell?

Thu May 28, 2020 8:19 am

I'm glad I came across this but sad I didn't do so one week ago. Was warming the engine for a trip, after replacing a graunchy-bearing original on Green Bus ('76 Westy) and had the stinky smoke storm with some fire. Fortunately keep a fire extinguish at hand so the damage is limited to the alternator wiring harness.

Will post some pictures of the disassembly/reassembly as I'm now getting pretty good at alternator removal/replacement.

Really too bad the specialty parts houses don't put a note in their sales sites or packaging, this seems to be a not-uncommon problem among those of us who maintain/repair their own vehicles.

Reasonable to expect the alternator and regulator to be otherwise OK?

Thu May 28, 2020 10:23 am

I just was rebuilding my alternator. Shortened the stud and ground the washers back. BE SURE to use a rubber boot over the stud as that saved my ass, and use the paper gasket. Also when you cut or grind the stud, DO NOT GET IT HOT. Hit it for a second or two and cool with some ice or freeze spray. Keep doing that cycle until you get to where you want to be. You don't want to cook the diodes. Watch the placement of the angle of the B+ wire also. If you look carefully in that photo above, it really looks to me like the wire crimp shorted against the cover, not the washer or stud.

Thu May 28, 2020 11:34 am

What boot are you talking about? The D post boot that is on 68-71 buses? Or is there one also for later years?

https://www.bughaus.com/generator_post_cover_-_113971901A.htm

Thu May 28, 2020 11:54 am

Couple of notes on alternator assembly:

1) there is no need for such a big-assed washer under the nuts which hold the positive diode assembly down. I'd replace them with smaller washers which are just big enough such that the nuts just cover them. Smaller washers won't reach the cover to short out.

2) orient the noise suppression capacitor wire terminal more towards the center of the alternator and away from the edge where it can short against the cover.

3) retrofit a rubber right angle boot (terminal nipple) on the main power wire such that it covers the (shortened) stud. If nowhere else, these are available from aircraft supply stores.

Thu May 28, 2020 12:01 pm

update - the style that is on the alternator now that I used in 2009 is the style that you linked at bughaus. They have them down at Bugformance too.

I am using this style now but I don't remember where I got them. Thought I had two but only this one is in my box for the present build. Either way the cover will flatten it a little. There are other brands too. I put a link under the photo for a similar one. Napa, Amazon, Summit etc - many places have alternator stud boots. It will help protect from shorts.

https://www.summitracing.com/parts/aww-500057?rrec=true

Thu May 28, 2020 3:27 pm

So, thought I had screwed up my alternator install and fried it. Was getting about 12.2 out it so something was happening. Took it out again and see that the brown wire that comes out of the alternator and heads into the harness is fried, broken. Red and green, which go to the voltage regulator are fine. That brown wire goes into a different part of the harness where splits from the wires to the voltage regulator. What's the wisdom on dealing with this? Will I need to cut open the sleeve that holds the brown wire and other stuff and follow it until I find good wire or what?

Alternator looks good. No evidence of shorts against the cover.

Thu May 28, 2020 3:31 pm

Why not just buy another alternator harness? How old do you think your current one is?

Thu May 28, 2020 3:37 pm

I'm looking at the replacement harness at the Bus Depot, but its not clear what happens at the split, where part of the wiring goes into the voltage regular and the second track heads up front. Haven't had to deal with this before so I don't want to do more harm than good.

Thu May 28, 2020 5:56 pm

bobby jay wrote: I'm looking at the replacement harness at the Bus Depot, but its not clear what happens at the split, where part of the wiring goes into the voltage regular and the second track heads up front. Haven't had to deal with this before so I don't want to do more harm than good.

Not sure what you mean by "heads up front"? The big red wire attaches to the big lug 12+ lug on the starter solenoid with all the other wires on it. That is perfectly normal for an alternator. There is a black wire for the dealer diagnostic system that can be tied back on itself or clipped off on either end.

Fri May 29, 2020 10:02 am

So, replaced my alternator. Red light stays on after ignition turned off. Appears battery not charging. Took it apart again and noticed the brown wire from the three prong plug out of the alternator was toast. Followed it up and it is not even connected to the voltage regulator. Just ends. Only the green and red go to VR. There is a blue wire that goes out of VR to another relay.

Not sure what's going on. Need some clarification. Anyone familiar with this?

Fri May 29, 2020 10:11 am

bobby jay wrote: So, replaced my alternator. Red light stays on after ignition turned off. Appears battery not charging. Took it apart again and noticed the brown wire from the three prong plug out of the alternator was toast. Followed it up and it is not even connected to the voltage regulator. Just ends. Only the green and red go to VR. There is a blue wire that goes out of VR to another relay.

Not sure what's going on. Need some clarification. Anyone familiar with this?

ask Telford. Was the brown wire new damage or old that you missed before? The harness has to be good for the alternator to work. I have one that has 1500 miles and 5 or 6 years on it that I may sell for $45 plus postage in a few weeks but right now it is in use, and I don't have the new one from Kyle yet that will replace it. His are more than BusDepot but it will match the new FI harness he is building for me. Also have a used original one that I took off when I put this one on, it is in fair shape. Maybe $10 plus postage. I'll get it down later today and take some photos - list it in classifieds once I look it over for faults if anyone wants to look at it. Frankly someone is better off with a new or like new one but they cost more money on a tight budget.

Fri May 29, 2020 10:14 am

I'll keep an eye on the classifieds.

No, it thing the brown wire was old burn. I think I just missed it when I replaced the alternator. Fried it a few months ago and I think that brown wire was the acrid smell that came as a result.

Still wonder why it just ends inside the wire sleeve.

Sat Jun 13, 2020 7:01 am

Many thanks for all the documentation, this is saving a lot of troubles.
The pulley on mine did not survive the removal process. I have been trying to confirm that the P/N is 021 903 109A, for a 1975 bus, 55 Amps. All the after market I have seen so far are listing bus up to 1974. Outside diameter of my pulley is 3.68 in. Any advice on a good quality replacement would be appreciated. - Regards

Sat Aug 22, 2020 1:22 pm

Got a rebuilt Bosch alternator from Autoparts International. $120.

It looks like they have included a round “garrolite” washer on the B+ terminal.

Anyone else seen these recently? Or is the standard practice to continue swapping over the garrolite square from the old alternator?

Also, my old alternator has rubber bumpers, should I swap those over too.

Has anyone used cork as the gasket between the alternator and the cooling tin?

Sat Aug 22, 2020 5:05 pm

So I made a gasket out of cork. Traced it with the backing plate. I also made it a little bigger in some spots. Here’s a test fit and looking at the B+ terminal.

Seems like a good fit and I don’t think I need to do any trimming. There’s enough cushion between the post and the tin. What do y’all think? :-k

Sat Aug 22, 2020 5:15 pm

Time will tell, looks good so far.