[Megunticook]

I was feeling great today after installing a new coil, ignitor, and pretty much all the wiring in the ignition circuit (been meaning to do that all year). Fired it up and while it didn't sound any different at idle, or drive dramatically different, I thought it might have had a little extra pep under acceleration--then again I could've been imagining it. Well at least I don't have to worry about some corroded connection or bad part causing an issue some rainy night. Proactive maintenance, right?

On the way home I noticed my ammeter reading almost half into the discharge zone (lights were on). Hmmmm...what's up with that? I turned a corner and the needle jumped up into the charge zone momentarily, then back in D. OK, I thought, must be that maine BATT output stud that spun a bit when I threaded the nut on holding the ring terminal. Must be an intermittent connection there? The alternator repair kit just arrived a few days ago...guess what task just jumped to the top of my "to do" list?

So after getting home I pull the alternator to get it ready for the overhaul. What do I see but a big crack in the housing--well, so much for repair, may as well replace the whole thing (which I bought for $80 at NAPA seven years ago). Wonder how it cracked? I always use an old axe handle to adjust the belt tension, wouldn't think that would have the force to crack the (aluminum?) housing.

Did a quick survey of the alternators available at NAPA and Rock. Inclined to go with Rock this time--but which brand is the most reliable? They're all remanufactured, that's fine, I just want something I'm not going to have to worry about for many years. The Bosch ones seem like a good bet, but I really don't know the first thing about remanufactured alternators. Any tips appreciated.

Any other thoughts on ammeter reading? Am I missing something? I suppose I should double check the voltage regulator connection also...but in any case I want to replace the cracked alternator whether it works or not.

 

[bherder]

Well, yeah you want to replace that alt... The crack may have nothing to do with it, but still .. Cracked parts isn't a good thing...

So far as a rebuild, what you're paying for is to the extent that's it's rebuilt.
The cheaper ones, they just take it apart, clean it all up, put in a new set of brushes, a drive end bearing and put it all back together.
The 'good' ones will take it apart, clean it up, new brushes, new bearings at both ends, new diodes and new bolts and screws holding it all together.
BTW, the armature and windings rarely, if ever, go bad. Usually only if there is physical damage to it, like a bearing coming completely apart.

Anyway, like I say, the crack is not good, but I'm wondering if you don't have a loose connection somewhere in the charging circuit. Field or battery connection on the alt ... connections at the VR ... (Hey, didn't you say you had a semi-broken battery connection on the alt a while back?)

 

[Megunticook]

The 'good' ones will take it apart, clean it up, new brushes, new bearings at both ends, new diodes and new bolts and screws holding it all together.

Would Bosch fall in that category? They're not the most expensive, but not cheap either--the one I'm looking at (AL504X, 60 amp single pulley, see http://www.rockauto.com/dbphp/mfr,BOSCH,Electrical,2412,Alternator)
runs $65. My experience with Bosch has been impressive, but I don't know anything about their remanufacturing.

I'm wondering if you don't have a loose connection somewhere in the charging circuit. Field or battery connection on the alt ... connections at the VR ... (Hey, didn't you say you had a semi-broken battery connection on the alt a while back?)

Right--I had a thread a few weeks back asking about why the main BATT output stud on the alternator would be loose--it was turning a bit when I tightened the nut holding the ring terminal on. But other than that everything in the charging circuit has been cleaned up (mostly replaced) in the past year, so I'm 99% sure that all the connections are clean and tight. I was thinking that possibly that BATT stud was loose enough to be causing an intermittent connection. In any case, we'll see what happens with the new alternator (I guess this is also finally the push I needed to change that drive belt I've been meaning to change since last winter!)

I also had failed to replace that metal clip that secures the VR wiring plug when I bought a new plug (I soldered and shrink tubed the connections before I realized my mistake, and didn't have the heart to redo it all again--but I just did last night to be sure!).

My VR does not have a ground strap, there is one shown in the FSM wiring diagram. I replaced the mounting bolts with shiny new ones and cleaned the firewall thoroughly around the bolt holes (even sanded down to bare shiny metal). Maybe I should add a ground strap for extra insurance.

But would a loose connection the VR cause a total loss of charging current like that?

 

[bherder]

I've never bought a 'rebuilt' anything from Bosch, but I don't think I'd have any prob trusting that you're going to get a quality unit from them. I've bought switches, relays, electrical doo-dad's from them before and never any probs whatsoever.

I'd kinda' be leaning towards that semi-broken batt stud on the alt being your problem ... Especially when you say you go around a corner and it works and then you go straight and it doesn't. Sound like something is getting jiggled around and I would think that would be the prime suspect

Sounds like you did an excellent job making sure you have a good ground at the VR. Yeah, your FSM is right, I've seen (As well as my own rig has) a ground strap that runs from the coil bracket bolt to one of the mounting bolts for the VR.
My 'hunting squirrels with an elephant gun' philosophy is: You can NEVER have 'too much' ground..
That cheesy sorta' ground strap from the factory, I replaced with 4 gauge copper wire with copper lugs at each end. I've got ground running from the batt to: Engine block, cab, radiator support. Engine block to cab. I even ran a ground between the cab and bed then to the frame.
Overkill? Yeah, probably, but I know for sure I'm grounded six-ways-to-Sunday

So far as the VR causing a total loss of charge? I guess it can go both ways? Not really sure on that. (Hey Chump! Ya out there??)
I know the VR works off the 'field' connection(s) to regulate the voltage/amp output of the alt. I know a bad VR will allow either too much or not enough voltage into the system. I've never unplugged the VR and run the engine to see which way it would go.. (I might do that, just to see )

If you've got a little time to spare, read this...
Even morons like me can understand it

http://www.madelectrical.com/electricaltech/howitworks.shtml

 

[Speed Dragon]

I'd find a good reputable local rebuilder to build you one.

 

[Megunticook]

I've never bought a 'rebuilt' anything from Bosch, but I don't think I'd have any prob trusting that you're going to get a quality unit from them.

Agreed. Our local "crusty old mechanic" told me recently that the only relays he's installed that lasted any time were Bosch...

I've seen (As well as my own rig has) a ground strap that runs from the coil bracket bolt to one of the mounting bolts for the VR.

Ah, so that's where the thing is supposed to go. I've been thinking about putting one on mine--makes sense, as there's probably a lot less resistance if the VR can ground through the block to that honkin' 4 gauge cable running from the bock to the battery, rather than through all the dirty, rusty chassis pieces to the 10 gauge wire on the radiator support bracket.

You can NEVER have 'too much' ground..

Mr. Crusty Mechanic (who's been a GM mechanic for probably 40 years) says some of the GM stuff came (or comes? not sure if he meant years ago or currently) from the factory with ground cables from one frame rail to the other...sounds crazy, but apparently they had some issues.


I've also hear crazy things about aluminum in radiators and heating cores springing leaks in no time flat because of electrolysis caused by bad grounds (un- or poorly-grounded components will ground through the coolant in such cases, so I've read).

I'd find a good reputable local rebuilder to build you one.

Good call...I don't actually know any around here (small town), but I'm sure there are some around Portland or elsewhere. I think for convenience sake (time is the thing I have least of these days) I will trust Bosch to do the job right and have Rock Auto ship me one out. My old core is probably worthless with the crack, so I'll keep that along with the repair/overhaul kit and bearing and next go-around I'll maybe take a crack at rebuilding it myself. Doesn't sound like rocket science...

 

[88D250]

For what it is worth I try to stay away from rebuilds as much as I can. New cost more in the beginning but as a rule is cheaper in the long run. I would buy local that way if youy have a problem you can get it resolved quickly. I bought a new 120 amp Alt for an 88 D250 for around $143.

 

[Megunticook]

For what it is worth I try to stay away from rebuilds as much as I can. New cost more in the beginning but as a rule is cheaper in the long run. I would buy local that way if youy have a problem you can get it resolved quickly. I bought a new 120 amp Alt for an 88 D250 for around $143.

Well, I didn't know you could get a new alternator for my vintage truck. At least I haven't seen one anywhere. What's your source?

I would think a well-done rebuild would be just about as good as new, but as bherder says the quality varies a lot. Certainly the less-expensive rebuilds are probably not going to last all that long.

In theory I agree with you, though, it's cheaper in the long run to pay more upfront for something that will last (and save you time and hassle in addition).

 

[Megunticook]

Installed the Bosch rebuild and tested it last night on a little 8 mile round trip. Put on the brights, heater fan on high, ammeter needle stayed right in the center. Probably was that loose BATT output terminal on the old one.

Just to be safe, this time I only hand-tightened the nut on the output terminal--put the socket on her and just used my fingers to tighten it down. Seems pretty snug--I'll keep an eye on it.

Wonder how the housing got cracked? Hate to think I did that...maybe while levering it out with a tool to tighten the belt at some point. Just used my hand this time.

A little soon to say, but it looks like a quality rebuild (has the good 'ol "Made in USA" on it!). Has a 2-year warranty--Bosch will even pay for a tow or a jump-start if the thing sh-ts the bed while you're on the road. They seem like a pretty solid company.

 

[Speed Dragon]

Nice. I'd snug that nut up just past hand-tight w/ a 1/4-drive ratchet or something.

 

[62savoywagon]

The last rebuilt alt I got has a lifetime replacement on them. As long as you have your receipt!! Yes I went through 3 of them, but the last one has been good for 6 months so far!

 

[84 Ram]

I like using quality electronics, like Bosch. I agee with Speed I would tighten the batt. wire allitle past snug, vibrations will back it off and it will usualy happen when you are far from home with no tools.