alternator not charging

[bmw9818]

all lights went very dim, radio switched off car was limping!

great back to the garage! alternators a 325 one working fine prior, i changed the voltage pack from my 316i alternator as it was brand new id of thought all voltage packs are the same?

charging rate with heated seats radio hlights heater on full reads in at 9v at the battery and 12 with switched off obv with car on,

connections at alt are tight, thick wire to starter and red wire to alt all tight,

i did accidentally drop the alt from a height of about 3ft?

could it be the voltage pack as its arced in with the old 316i alt and not brushing properly?

[Brianmoooore]

Don't know if it's applicable here, but replacement carbon brushes for motors/generators in general are often supplied with the brushes locked in the fully retracted position to aid fitting. Once fitted or while being fitted a tab or some other locking device is released to allow the springs to push the brushes out.
If you fitted a new regulator pack with the brushes locked back it would probably arc for a while then quit.

[bmw9818]

Car doctored itself! After a drive during the day, all items switched off, it went up to 14 and after another drive it's up at 14.3!

Think brushes just needed time to rebed themselves into the new alternator,

[bmw9818]

okay so it seems to of dropped back down to 11.3.... car just limped wipers died lights dimmed! got it back home, batt connections all tight engine ground tight,

im puzzled? how can the alternator drop back down to 11 after a week or so? belts tensioned near enough on max

[Speedtouch]

Perhaps you have an underlying fault that caused the original problem.

Best to remove a battery lead and use a multimeter to test for any leakage current with the ignition switched off - it should only be in the order of a few mA.

[toby]

Earth strap between engine and chassis intact?

[bmw9818]

earth strap and all connections are tight... i did a coolant bleed quite a bit came out and fell on the alternator could that be the issue?

[Speedtouch]

Doubtful, but best to let the alternator fully dry out - perhaps use a hairdryer on it - and try again.

[bmw9818]

Very odd! I blew it with some air, removed the pack one was shorter other was longer however longer ones slightly wobbly... Probably not brushing?
Might have got dislodged over a bump, just pulled it out and back in, 12.7v after a drive up to 13.9..

Might invest in a new pack

[Silverfang]

I had similar issues with my alternator, having gotten a new brush pack installed and tested a few years ago. This lasted for 2 years before this November.
Unfortunately the alternator packed up and was not charging period, and considering it was the original one (Or looked like it given the corrosion!) It was easier to get a exchange unit from GSF Parts than try to poke the old one back into life, for the sake of £90 I'd rather have peace of mind.

[Captain_Birdseye]

I would do what silverfang suggests but only from my own experience - which is limited... like your voltage.