Alternator vs Regulator

SoDoWarts · Post by **SoDoWarts** » 28 Jun 2010, 15:42

Help. The other day I had to jump my (one year old) battery and it was up and running fine until I turned the car off a half an hour later. AAA battery service shows up and their 5 minute test with a printout says that the battery is "severly discharged" but the altenator is fine. Said to have a trickle charge done which I did at a service station and he also said the alternator looks fine. But later that day it died again and I got it to Autozone where I had bought the original battery. That guy did a test which said the battery is dead and alternator is fine. Got a new larger battery (first one was probably too small) and two days later the car cut out while I was driving! It will not keep a charge - and it was just two days old! Had it towed to my volvo guy and now he's telling me that it needs a new alternator which costs $500 for the part and $200 to install!!!

Is it possible to tell if the voltage regulator is bad as opposed to the alternator being bad? To my understanding its alot cheaper to replace a regulator! Thanks for any help you can supply.

Post by **JDS60R** » 28 Jun 2010, 15:54

You didn't metion what year or model you are dealing with. Most of the info is generic so here goes.

You don't need a Volvo guy to do an alternator. Any garage (or yourself) can easily do this in an hour or so. A remanufactured alternator should run you $100 to $150. Some of the models had issues with corrosion in the cables. You will want to check the cables thoroughly for corrosion. Post pics if you find anything. I spent 14 years in MA and they have some great rebuilders there. But getting one from Advance or autozone is fine too.

Please don't pay $700 to have an alternator put in. If you disconnect the battery first it is very difficult to make a mistake. This way you will have good bearings, diodes, stator,winding and regulator.

Tell ue which model and I will post the procedure for you. If not - any local mechanic will be capable. You disconnect the batt ,remove the serpetine belt, unbolt the power steering pump,repalce the alternator and then put it back together.

Post by **JRL** » 28 Jun 2010, 19:21

I would look to both your battery cables first
This is about that time (0-14 years old)they're all going bad and yours may be real bad
It won't show on a check until you run it for say 1/2 hour, then try to touch the positive cable, if it's too hot to the touch that one is bad.
Remove your fuse box cover, look at where the B+ cable is connected, (R/F of the box) if it looks corroded that too is bad!

Post by **cn90** » 28 Jun 2010, 22:30

Why don't you rebuild your alternator using quality parts? Total cost for rebuild is $60 for parts (see below).

I wrote a DIY for my 1998 BMW 528i. The main difference between BMW and Volvo is the Front Bearing.

http://www.bimmerfest.com/forums/showth ... ?p=5209013

For the Volvo, this is what you need. Avoid using Chinese bearings!
1- Front bearing: SKF (or Koyo, NTN, F.A.G.) 6303-2RS....about $8-10 on ebay
2- Rear bearing: SKF (or Koyo, NTN, F.A.G.) 6203-2RS...about $8-10 on ebay

3- Brush Holder about $40. Call Dave for quality HUCO brand Brush Holder:

Smith Co. Inc.
530 11th St.
Greeley, CO 80631
USA
Phone: (970) 353-3121
Ebay seller name "smithcoelectric".
http://www.stayingreen.com/5.html

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Typical Bosch Alternator layout:

: Bosch-Alternator.JPG (95.68 KiB) Viewed 2919 times

boiseone · Post by **boiseone** » 29 Jun 2010, 09:39

Heads up on this battery problem. My daughter just went thru three bad batteries in a row from one of those chain auto parts stores. All failed in a really short time and all had bad cells. With the third and most recent replacement her 93 850 is running fine. I too thought it was an alternator problem but it wasn't. My advice would be to buy a totally different brand battery ( see Bob is the Oil guy website ) and see if that fixes the problem. I always use genuine Volvo batteries and have never had a problem.

SoDoWarts · Post by **SoDoWarts** » 29 Jun 2010, 10:03

Thank you all! IT's a 2000 C70 conv. What about the thinking that it could be just the voltage regulator? I've read that many times thats the actual problem. I can get a Bosch regulator (part # 8637851) for $65, and that looks to be a bit easier to install for a car sap like me. Let me what you think. Any info/pics on installing either the alt or reg would be greatly appreciated. Thanks again!

Post by **jblackburn** » 29 Jun 2010, 10:09

Yes. If your alternator sounds OK, just replace the regulator/brush assembly. The alternator itself still has to come out of the car, though...there just isn't enough space to get to it with it in there, even with the PS pump out of the way.

You may be replacing it again later on when the bearings in the alternator go out, but who knows. I had one go out in a car at 80K, one at 200, and one was still original at 20 years old. But just replacing that will save you money for now.

Post by **shiloh51933** » 29 Jun 2010, 11:13

My theory is if you gotta take it out(alternator) anyway, just replace it with a new one and I mean new not reman. 700 beans for an alternator install/replacement is fukin' ridiculous!!!! Do it your self or find some one else.

Post by **cn90** » 29 Jun 2010, 11:41

Once the alternator is out of the car, rebuilding it takes only 30 minutes!
Rebuild alternator yourself!

Post by **JDS60R** » 29 Jun 2010, 14:01

Here are the procedures for removal