I replaced the Alternator on my daughters 93 240 a few months ago and all seemed to be fine until last week when all the dash warning lights went on. The lights were off at the next start up and stayed off until she came home for me to check for problems.

I checked the car this weekend and the alternator appeared to be fine, it was charging at 14.2 volts, battery tests fine and holds a charge. She has noticed a flickering of the bat/alt light on the dashboard.

On her way back to her home all dash lights came on again but this time stayed on this time. She has a DVM and says voltage at the battery is down today to under 12 volts.

I'm not sure what the problem is any ideas are appreciated.
Thanks
Dan

The alternator has developed an internal rattle, it sounds like it's full of marbles? One of the bolts holding the case together backed off a turn or two but tightening it did nothing for the rattle?

When I trigger B+ with an alligator clip from D+ I get an electrical whirring sound and the alternator doesn't seem to be working?

Dan

When you get it apart and examine the rear bearing, look at the rear case end where the bearing sits.

There is a plastic cup that holds the rear centered in the case --- if it's cracked or damaged the rotor will wobble.

The alt in the 93 should be an 80AMP B-AL157X (from my RPR catalog) 1988 - 93

In my 87 ---- 70AMP B-AL57X ----- that plastic "Tolerance Ring" failed.


TOLERANCE RING 46-91550
https://www.aspwholesale.com/alternator-parts/bosch/tolerance-rings.html

https://www.aspwholesale.com/alternator-parts/bosch.html

I have the alternator out, but having trouble splitting the case what am I missing?
Dan

Bigger hammer? I assume you have the bolts out. Last one I had trouble with I thought about applying the chisel tool that came with a Bosch hammer drill, but eventually worked the cases apart with a large flat screwdriver and a hammer.

All depends on the level of aluminum/steel corrosion. I didn't notice mine rattled until I got it off of the car. All the balls from the rear bearing were bouncing around inside the unit along with the torn-up cage.


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Art Benstein near Baltimore

Vacuum Connoisseur:
I am perfectly comfortable with partial vacuums, however, I'm partial to perfect vacuums.

I found a video taking apart a similar VW alt and that's how they did it!
No corrosion it literally looks new.

I have never heard the noises from an alt that this was making. I suspect the problem is with the rectifier, is their an easy way to test it? I have installed another alt hopefully good used unit but haven't tested it yet.

The one that failed is only about a month old but has been sitting on the shelf for a year or so. I tested it a couple of times again before I took it off, the last time their were no noises but it was not working. It really made a racket when it was working!

I still need to replace the B+ wire to the cluster.

The alt is tested an works when triggered!

Dan

The rectifier doesn't make noise unless it has physical damage and the rotor is interfering. Sounds to me like you'll find exactly what CeeBee is talking about. When the rear bearing seizes, it makes a mess of that plastic cup that seats it in the housing casting.

To get it all apart and replace the bearing, plastic cup, and (in my case) slip rings you'll need some gear or bearing pullers, a press or large vise, and a heavy-duty soldering iron.

I don't know an easy way to test the rectifier assembly. You need it run in the car, or a stronger bench-mounted electric motor than I have, a carbon pile load like you test batteries with, and an oscilloscope. Don't know, but I doubt the auto parts stores can do much more than check the output current/voltage. I'm probably wrong about that assumption.
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Art Benstein near Baltimore

I'm so busy I don't know whether I found a rope or lost my horse.

Thanks Art & CeeBee1

I probably won't mess with the month old alternator right away, it's hard to believe a bearing is bad but maybe Bosh remans are no better than anyone elses rebuilds!

I'm on to the exiter wire, it looks like pin 11 on the round connector is what I need to intercept, it's the only red wire going on the cluster.
Dan

All done and it's working fine, we will see for how long! My Daughter is loosing faith in old faithful.

From where did you get the replacement?
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Art Benstein near Baltimore

PUBS. The official sunblock of Ireland.

Hey Art how is it going!
It is a Bosch reman I got on ebay.
Dan

Hi Dan,

I've had my share of alternator issues. Last one nearly ended my love affair with 240 Volvo due to the potential impact of a breakdown at an important time and place.

Yes, it is intermittent, so not being your own car to drive, you are forced to go with the likelihood percentages. I'll lend what I can of my experiences which point to the reman alternator rather than the wiring, given (1) it is a 93 with no gray firewall plug, (2) you wired it up, ground and all, so the labor is a known, and (3) you'd have said as much if the original reason you replaced it was the same symptom.

Check the brushes and look at the slip rings, at least using a mirror and light. Bosch reman sounds excellent but could, on ebay mean, reman Bosch.

The cause of my recent trouble was the disintegration of the bearing, with a piece of the cage shrapnel eventually shorting the regulator output. On the other hand, after I replaced that bearing and the slip rings, I got the case clocked wrong by one screw and was just briefly tempted to go ahead and install it. But I realized the wiring was brittle with manifold heat and oil, so bending it to match the new position of the terminals would invite trouble down the road with the wiring and the clamp holding it in place.

You could also use a small bulb or even a jumper wire (bulb not necessary) to temporarily provide D+ to the regulator from the B+ terminal in substitution for the small red "stim" wire, if you suspect the trouble is external to the alt, but this arrangement needs both to be mechanically secure and easily disconnected when the car gets parked. If I wanted my daughter to try this, I'd make up a jumper for her in advance with a ring terminal for the B+ and a faston for the D+.
--
Art Benstein near Baltimore

My wife says I only have 2 faults. I don't listen and something else...

Art
I have been pretty lucky with alt problems, I believe the one I replaced was the original ( but not the regulators / brushes)it did seem to have a little sloppy front bearing. I thought replacing the alt with a new reman solved the problem but 2 months later it's back.

I also had the problem of the case not being clocked like the original and I may have caused my current situation!

It is genuine Bosch reman with tags and all(yes ebay can be very misleading), the other day it was reading 14.2 volts at the battery and she almost got home with it before all the warning lights came back on.

I did replace this wire on my 85 but as you point out there is no connector on the firewall in 92 or 93.

I will try jumping B+ to D+ to test it but I can't leave it that way.

Is replacing the wire to the cluster acceptable? I do have cracked insulation on the small Red wire that I can see but it is not where it can short out easily so it must be hidden in the harness.

My daughter is beginning to understand these old Volvos don't actually run forever without some attention now and then.

It doesn't help that temperatures are in the mid 90's already here in FL.

Thanks again
Dan

Alternator exciter wire is probably getting grounded or alternator exciter terminal is grounded when engine is running. Since the problem is intermittent you have to test it while its happening or hook a temporary test lead to a meter inside the car to catch it happening.

Thanks, I'm not sure why 1981 shows up in your reply? I may not have RE_SET the date when I posted?

The car is going to be here tomorrow, I will probably just run a new wire from the cluster it should be a red wire right. The old or current wire's insulation is cracked where it is visible so you may be on to something.
Thanks
Dan