Bosch Alternator Reconditioning

[COL]

I bought four Bosch alternators for $10 2@70A; 1@85A; & 1@55A

Below are pictures of condition these alternators were in when I got them. This is one of the 70A alternators that I think were on the early 90's four cylinder Mitsubishi Magna. I will be using it on my Renault R12 wagon restoration when the time comes.

 

[COL]

After a bit of cleaning of the major components; machining the slip rings; and removing seized screws the parts now look like this.

 

[COL]

Rectifier assembly installed in rear housing.

Stator installed with the 3 outputs soldered to the rectifier assembly

New brushes installed

New bearing in the front housing with rotor installed.

Complete alternator assembly

Regulator and capacitor installed


All I need now is an offset "V" pulley and I might have to fabricate a mounting bracket to align the pulley with the water pump pulley on the Renault R17 motor.

 

[robmac]

I harvest my alternators from pick-a-part. The going price for a a holden "v" series commodore bosch 80 amp alternator is $30.

Choose one that looks newish and expect to replace the bearings. Paris- rhone or ducellier v pulleys fit straight onto the bosch.

 

[COL]

I harvest my alternators from pick-a-part. The going price for a a holden "v" series commodore bosch 80 amp alternator is $30.

Choose one that looks newish and expect to replace the bearings. Paris- rhone or ducellier v pulleys fit straight onto the bosch.

These were harvested a few blocks from home, the nearest wreckers here is 50 Km away. Unfortunately the previous owner of them didn't store them in an ideal location, but they cleaned up reasonably well, actually better than I thought they would.

I have a completely reconditioned alternator for the princely some of $25 and a few hours work. Most alternators of this age will need new bearings, brushes and the slip rings either replaced or machined. I got to christen my media blasting cabinet as well, which works a treat.

I have some offset pulleys here that suit a 17mm shaft, but they are attached to SEV Marchal alternators which I reconditioned a few years ago so may go hunting for some R16/R17 alternators that are beyond repair.

 

[R4gene]

View attachment 128716
Rectifier assembly installed in rear housing.

View attachment 128717
Stator installed with the 3 outputs soldered to the rectifier assembly

View attachment 128718
New brushes installed

View attachment 128719
New bearing in the front housing with rotor installed.

View attachment 128720
Complete alternator assembly

View attachment 128721
Regulator and capacitor installed


All I need now is an offset "V" pulley and I might have to fabricate a mounting bracket to align the pulley with the water pump pulley on the Renault R17 motor.

Nice job, good to see a part repaired rather than thrown out and replaced. I was told today my Fuego’s alternator was not working and needs replacement but since it works intermittently I’m sure I can get it functional. It wasn’t in his mind to even try fixing it. I understand the pressures of turning a buck and time is money but it is wasteful and perhaps lazy?

 

[COL]

Nice job, good to see a part repaired rather than thrown out and replaced. I was told today my Fuego’s alternator was not working and needs replacement but since it works intermittently I’m sure I can get it functional. It wasn’t in his mind to even try fixing it. I understand the pressures of turning a buck and time is money but it is wasteful and perhaps lazy?

Its most likely the brushes that need replacing. I would also check the condition of the slip rings, there maybe a big groove down the middle of each one. The slip rings can be machined if there is enough copper left on them or replaced.

While you have it apart you may as well replace the bearings, the are about $6 from your local bearing place.

 

[Bowie]

Thank you for bumping this thread. My original alternator with external regulator is on the list to look at, I confess I’m tempted to just buy a new something and be able to bin the external regulator..

Who was it here that ended up with a new Toyota alternator in there 12?

 

[R4gene]

Its most likely the brushes that need replacing. I would also check the condition of the slip rings, there maybe a big groove down the middle of each one. The slip rings can be machined if there is enough copper left on them or replaced.

While you have it apart you may as well replace the bearings, the are about $6 from your local bearing place.

Hi Col, thanks for the tips. I will get on to pulling the alternator out this weekend. I’ll try and find a working replacement to keep the car on the road in the meantime. Matt

 

[COL]

Hi Col, thanks for the tips. I will get on to pulling the alternator out this weekend. I’ll try and find a working replacement to keep the car on the road in the meantime. Matt

Sounds like a good plan to me.

I keep spare alternator and starter motor for my cars for this very reason, swap out the faulty unit and repair at my leisure

 

[REN TIN TIN]

Thank you for bumping this thread. My original alternator with external regulator is on the list to look at, I confess I’m tempted to just buy a new something and be able to bin the external regulator..

Who was it here that ended up with a new Toyota alternator in there 12?

Don't know about the Toyota, but I put a Subaru alternator in my 12 (Toyota might be the same).
Only needed minor fettling to get it to fit and gives 85 amps ISO the 35 amps from the standard alternator.

Cheers
RTT

 

[jaahn]

Hi
I took about a dozen of those old Bosch alternators to the scrap last year. They would mostly have been fixable and the parts are often interchangeable over the years. It was not usual to 'blow them up' really and as Col said brushes and possibly a skim is often the only problem. Later ones a regulator may be necessary but easily bought and replaced. Bosch are more reliable than other brands IMHO.
But there are 1000 different frames made to suit the different engine brackets. Possibly more ! Soo look at getting a frame with lugs that suit your engine brackets as that is the hard part to do. There is no standardisation in this and it is getting worse. Generally speaking any alternator will be OK for an old car and will put out more than enough current to do what ever you need.
Jaahn

 

[tanjo40]

hi col. can you please tell me the slip rings part number. i would really appreciate it

 

[COL]

hi col. can you please tell me the slip rings part number. i would really appreciate it

there are few here on Ebay, you will have to measure the slip rings that you have and compare.

bosch slip ring for sale | eBay

Find great deals on eBay for bosch slip ring. Shop with confidence.

www.ebay.com.au

 

[run205]

well done, good work
good pics and explanation too (only off a P205 Diesel not a magnificent magna)
I had one the same that killed two batteries,
bled all the charge out of one overnight, then I assumed it was the regulator and replaced it
but it wasn't so it killed a brand new battery the next time it was installed
then I realised its ok to use the Si petrol alternator, der

 

[COL]

well done, good work
good pics and explanation too (only off a P205 Diesel not a magnificent magna)
I had one the same that killed two batteries,
bled all the charge out of one overnight, then I assumed it was the regulator and replaced it
but it wasn't so it killed a brand new battery the next time it was installed
then I realised its ok to use the Si petrol alternator, der

Sounds like you may have a diode issue with your alternator.

 

[run205]

Sounds like you may have a diode issue with your alternator

pretty sure you're right, only I learnt that the hard way
and it's had not "have"...
after killing 2 batteries and the waste of time and money on a reg, it was flung at the scrapyard

 

[AlexB]

I had one the same that killed two batteries,
bled all the charge out of one overnight, then I assumed it was the regulator and replaced it
but it wasn't so it killed a brand new battery the next time it was installed

I'm not sure if it's always the case but I have a few times observed that a blown (shorted) diode energizes the windings such that I am unable to turn the alternator by hand when I turn the ignition on. Quick fix is to then measure the diodes, cut out the shorted diode and reassemble, I had a Discovery I and it still charged at 13.8v with just 4 diodes (out of 6), it's just the amperage is reduced.

 

[COL]

I'm not sure if it's always the case but I have a few times observed that a blown (shorted) diode energizes the windings such that I am unable to turn the alternator by hand when I turn the ignition on. Quick fix is to then measure the diodes, cut out the shorted diode and reassemble, I had a Discovery I and it still charged at 13.8v with just 4 diodes (out of 6), it's just the amperage is reduced.

Depending on which diodes you cut out the alternator was probably only working on 2 phases.

Its not hard to change the diodes, they are in two groups of three.

 

[AlexB]

Depending on which diodes you cut out the alternator was probably only working on 2 phases.

Its not hard to change the diodes, they are in two groups of three.

I just needed to move it around the yard and not destroy the drive belt (you could hear it groaning) and battery as occured to @run205
The average alternator with three Alternating Current phases can still charge with either the positive or the negative part of the phase not getting rectified so it was technically 1 full phase and two half phases.