Hi all,

My alternator light comes on sometimes at idle, lights dim and alternator light turns off with some revs. I have done some research on the forum and seems to be the voltage regulator.
I have a tf magna, Bosch alternator with the regulator on the outside.

I found this on eBay
http://www.ebay.com.au/itm/RE72-Alternator-Voltage-Regulator-RE-72-Bosch-style-/121090066040

Is this the correct replacement? And has anyone installed one before? What's involved with installing it?

Thanks
Dayne

could just be brushes inside the alternator, check voltage(14.2) at battery, then turn on headlights and check again

to check, disconnect negative on battery, undo with screwdriver, brushes are soldered into housing, but if your brushes are knackered, there's a good chance your bearings are as well

low klm one from a wrecker, would be better, or a reco one from an auto sparky

I don't get this, seriously, replace the alternator if its making a noise, or if a diode has collapsed, start the car, let it idle, get your multimeter out and check the voltage at the battery, should be 14.?v. but from your description it sounds like the regulator, if your having no other problems with the alternator, then save yourself some money and just replace the regulator.

No noisy bearing, no other problems just every now and again at idle the light comes on.
I'm not replacing the whole alternator when I can just replace the regulator. I don't see the point on wasting money for no reason. Some people like to put new parts on old cars, for peace of mind or whatever. I'm not bothered. It's my way of recycling and doing my bit for the environment. Plus I'm a tightass......

What I want to confirm is the re72 regulator the correct one ???????
For anyone that has changed one any tips for installing it???????

Not sure if its the correct one or not, maybe some one here can tell you, but replacing the reg is simple enough, look to the back of the alternator to where the wiring harness plugs in you will find 2 screws, make sure the battery is disconnected, undo the screws and the reg will probably feel a little springy. just wriggle it out, you will see where the brushes rub on, installing the new reg is in reverse.

Hi all,

My alternator light comes on sometimes at idle, lights dim and alternator light turns off with some revs. I have done some research on the forum and seems to be the voltage regulator.
I have a tf magna, Bosch alternator with the regulator on the outside.

I found this on eBay
http://www.ebay.com.au/itm/RE72-Alternator-Voltage-Regulator-RE-72-Bosch-style-/121090066040

Is this the correct replacement? And has anyone installed one before? What's involved with installing it?

Thanks
Dayne


I bought one of those cheap ebay regulators, it only lasted one year, that was for a TS magna, not saying they all only last a year but thats just my experience with them

I bought one for my TS as well, but never got to fit it. So no help from me. lol

Not sure if its the correct one or not, maybe some one here can tell you, but replacing the reg is simple enough, look to the back of the alternator to where the wiring harness plugs in you will find 2 screws, make sure the battery is disconnected, undo the screws and the reg will probably feel a little springy. just wriggle it out, you will see where the brushes rub on, installing the new reg is in reverse.

Sweet I was hoping there wasn't any soldering involved. Thanks for that :)

If the regulator only lasts a year I'd be happy with that. $27 isn't a lot of money considering if I got a second hand alternator I'd be up for at least double that with 3 month warranty.

regulators rarely die, that ad on ebay is misleading

its usually just the brushes and if they're gone , your slip rings wont be much better

im a retired auto sparky

I don't know that much about alternators but are the brushes the metal thingys on the end of the regulator?

I don't know that much about alternators but are the brushes the metal thingys on the end of the regulator?

Yes they are

So replacing the regulator will give me new bushes which solves my problem.........I'm guessing most non Bosch alternators have the bushes separate to the regulator?
I've replace many an alternator on the many many many shitboxes that I've owned. I never knew you could replace the regulator and get new bushes....

you know now ,

btw theyre not bushes/bearings mate, theyre brushes and they wear out

are the brushes the metal thingys on the end of the regulator?


theyre actually carbon not metal

and are soldered in behind a spring

cheaper than the regulator/brush housing

theyre actually carbon not metal

and are soldered in behind a spring

cheaper than the regulator/brush housing

Oh cool so as the brushes wear out the spring pushes them out/toward the centre of the alternator. Thanks for the info btw. It must be painful having many years experience and listening to noobies like myself asking stupid questions....

The only question that is stupid is a question that didn't get asked.

I think I'm quoting someone there . . . lol

Brushes - about $5 for the pair last time I put some in.

It must be painful having many years experience and listening to noobies like myself asking stupid questions....

nah mate im always asking questions here myself .... i only ever worked on 1st and 2nd gen magnas and now own a 3rd gen

Just an update I ordered the regulator. Hopefully comes over the next few days.

Also checked battery voltage at idle with battery light on with headlamps on = 11.97v
Battery voltage above idle, headlamps on without battery light on= 13.8v

Voltages as I expected, voltages running ok normally, but at night when the battery light comes on lights dim.

I hate waiting for part in the post....

Replaced the regulator this morning. Brushes were sticking out of the old regulator about 8mm. Compared to new one of about 20-30mm.

Reading 14.5 volts at the battery now and im pretty confident that i wont get a battery light at idle but time will tell. Thanks heaps every one. I learnt a little and saved myself some money. Great success. Lol

Just had the battery light come on and stay on....... I'm gonna replace the alternator with a good second hand unit.
So alternator isn't charging, battery voltage was 12.7v.
Swapped back to old regulator and same symptoms as first post. I'm guessing I bought a faulty regulator? Or is there something else it would be?
Strange that I change back to the old reg and all is how it was. How do I check if regulator is working? ( I have a multimeter)

Check that the connections to the alternator are correctly fitted. One of the leads may have fallen off or be lousy contact.

I bought an RE72 regulator off eBay years ago for a spare alternator for my TS, but never got to fit it, so quality wise it is an unknown.

As above, check leads. Also check alternator output lead (the thick one from the alternator) up at the battery connection.

Another thing that can happen with the alternator is that diodes (9 of them in there) go open circuit (= no output) or short circuit (= battery goes flat, alternator gets hot overnight).

Sounds like the reg may have already died.

Unfortunately that's what happens with cheap ebay cr*p.

1. Get a refund from ebay
2. Take it to someone who knows what they are doing (qualified auto elec)
3. When they give you two options for replacement parts (like a cheap replacement regulator or an expensive genuine one), go with the more expensive one. It is always cheaper in the long run.

By the way, your problem could be:

1. Intermittent alternator which needs to be put on a bench rig and tested properly at high load to positively fault, or failed bearings causing subsequent belt slippage & alternator under speed at low rpm
2. Wiring/earthing problem
3. Diode pack
4. Regulator
5. Battery with internal fault causing the voltage sag at low rpm.

Get a professional.

By the way, your problem could be:

1. Intermittent alternator which needs to be put on a bench rig and tested properly at high load to positively fault, or failed bearings causing subsequent belt slippage & alternator under speed at low rpm
2. Wiring/earthing problem
3. Diode pack
4. Regulator
5. Battery with internal fault causing the voltage sag at low rpm.

Get a professional.

I will either get a second hand alternator or swap the brushes over to the old regulator. I am not taking it to a professional.....
I like to problem solve myself. I haven't given any of my cars to a mechanic / auto leccy in about 10 years and I don't plan on starting now. I like these forums cause they are full of knowledge on here and people seem to help when it's needed. This is how i learn about my cars........this is how I get to know my cars and this is how I get away with owning all the cars I've ever wanted to own.....lol

I will not bother with another eBay crap one again. I've already asked for a refund so we will see what happens It was working fine for the 3 days. Then bam stupid light came on.

The only thing that I changed was the regulator and attached brushes. Brushes are still fine on the broken regulator but its not charging. It was charging happily for 3 days even at idle speed. I'm running the old reg now with the warn brushes and the battery is keeping charge.

As you suggested flyboy, the new regulator seems to be the culprit, I will have a look at possible wiring issues over the next few days.

Thanks for the suggestions. :)

Change the brushes over. They are only soldered in.

When I had alternator problems with my TS, I bought a second hand one from the wreckers, which didn't work. So I went back, got another which didn't work either. Changed it for a starter motor and took my original alternator to get exchanged for a $150 recon job, that blew up too but it was warranted so I got it exchanged.

Alternators can be a real PAIN! But you already knew that! lol

Just an update, I tried to solder the new brushes but the attached wire wasn't long enough to put the spring in and get through the holes. I just bought a borsch regulator for the sum of $75. Swapped in in and haven't had a problem since. :)

Thanks for all the help gentlemen. Although I could have just replace the alternator this has been a fun trying to fix it on my own.

Cheers,
Dayne

generally the spring is a lot longer than the flexible wires which are embedded into the brush. So you have to tie the spring closed with fine wire, then solder, then pull the fine wire out. The when reassembling, yo have to jiggle /juggle/ fiddle around to get the brushes over the slip rings. Maybe there's a little hole in the brush holder where you put a pin in to hold the brushes inside the holder until you get the thing assembled.