Electrical: alternator not charging

[BGA]

Alternator on my 245-85, bosch, is not charging enough.
Charging indikator lamp is okey, but lights a little (together with some other warning indikator lamps) at low idle, but I am used to this behavour with old Volvos.
Battery voltage reading is:

Engine not running: no load 12,65, loaded 11,0

Engine at idle: no load 13,6, loaded 11,7

Engine 1500rpm: no load 14,0, loaded 12,0 volt

Load is headlight + fan.

Brushes are not worn, and battery is new.

How can I check if it is a faulty regulator or diod?

[Paul240480]

I'm pretty sure that the brushes & regulator are all one bit. Just held on with the two screws on the rear of the alt'.

I replaced mine about 18 months or so ago. Just because the ignition lamp glowed dimly at tickover. On the move all was fine. My brushes were 'low' but not right down to the end.

Mine was £14.99 from Braydons delivered to me in France, so not a major outlay & if not the prob you'd have a spare at the ready

Just seen yours is an 85', if that means it has a separate regulator in the wing, then they can be quite difficult to source I gather. If worst comes to the worst, you could swap alternator for a later type.

Not sure how you'd test the reg' sorry.
Good luck.

[740 Driver]

Hi

Bad news is you have to take the alternator apart in order to check the diodes. The voltages you measured are a little lower than I would have expected. How about checking the simple things first such as belt tension, the earth connection to the alternator and the main connection on the back of the alternator.

On the early cars with the separate regulator its worth checking the connectors in the lead between the regulator and alternator. Some of the early regulators had provision to adjust the voltage but we always did that with the alternator and regulator on a test bench rather than on the car.

Best idea is to get a newer type of alternator with the built in regulator and give that a try.

[dan 244]

Originally Posted by 740 Driver

Hi

On the early cars with the separate regulator its worth checking the connectors in the lead between the regulator and alternator. Some of the early regulators had provision to adjust the voltage but we always did that with the alternator and regulator on a test bench rather than on the car.

Best idea is to get a newer type of alternator with the built in regulator and give that a try.

I think the alternator changed to the all in one with no seperate regulator in the 1981 model year so should be all in one on your car.

[redboy]

yep- definately the alternator diodes- I had the same problem- light bulb, brake, and alt lamps lit dimly. I first replaced the brushes but that didn't solve the problem, so it was the diode pack. I also noticed the bearings were a bit noisy- so it was worth replacing the whole thing. I put a new alternator on and it solved the problem.

There's a new Volvo 240 alternator- Bosch- looks like internal regulator too- on ebay with a buy it now for £38 at the moment.

cheers,
Brian

[redboy]

Oh- and if looking at alternators, bosch internal and external regulators are interchangable. I bought an external regulator alternator for £20, and just replaced the brush pack which is connected to the plug for the external regulator wires with a £7 internal regulator/brush pack and bang- internal regulated alternator!

[BGA]

Its a build in regulator. Belt tension and connectors are checked. I guess Redboy is right. I will check the diod bridge asap.

Thanks for all replays.