Greeks Posted September 24, 2011 Share Posted September 24, 2011 Went out to get a takeaway tonight. 8 miles or so 50 mph, lights on.All the way home the red ignition light stayed on.Belt's nice and tight, lights not dimming under any condition.Battery is about 3 months old - direct replacement for the previous which lasted about 8 years. Checked last week and water levels were spot on.ALternator's only 5 years old ... but sounds like it could be kaput.Any thoughts?Are the 15AC (I think) alternator's repairable in any way? Link to comment Share on other sites More sharing options...
mikeyb Posted September 24, 2011 Share Posted September 24, 2011 did you measure the voltage? Should be 14.5 ish accross the battery with engine running.If voltage still good, maybe diode gone in alternator Link to comment Share on other sites More sharing options...
Greeks Posted September 24, 2011 Author Share Posted September 24, 2011 MikeyB wrote:did you measure the voltage? Should be 14.5 ish accross the battery with engine running.If voltage still good, maybe diode gone in alternatorGod no ... wasn't gonna let the Thai food get cold ;D... but i'll check in the morning - cheers.The battery has one of those windows (green light for good, etc) and it didn't show green, so presumably not charging :-/ Link to comment Share on other sites More sharing options...
andy thompson Posted September 24, 2011 Share Posted September 24, 2011 Original Lucas good for 25+ year (so much for prince of darkness reputation) anything rebuilt with cheap Taiwanese diode pack - you were lucky to get more than 2 years - solution? Understand diode specs and get something aerospace grade ( probably ?3 rather than 3p)If you work it out please enlighten us! Link to comment Share on other sites More sharing options...
piman Posted September 24, 2011 Share Posted September 24, 2011 Hello Greeks, I never bother with 15ACr repairs except for a quick check on the brushes, (easy and cheap repair) as they are so cheap on exchamge. (Well they were last time i got one which is a few years ago0 Funnily that showed a dull ignition light but the voltmeter was way past 15V so it was overcharging. (Not good for the battery).Alec Link to comment Share on other sites More sharing options...
Nick Jones Posted September 24, 2011 Share Posted September 24, 2011 Usually it's the internal regulator assembly. They are available and cheap, but quality is very suspect. I gave up with them some time back and went Bosch. The later Lucas items (forget the no) are also a big improvement and an easy swap.Nick Link to comment Share on other sites More sharing options...
Greeks Posted September 24, 2011 Author Share Posted September 24, 2011 This morning's diagnosis says 13 volts - no light at idle, but comes on as revs go up.Nick - am I right in thinking I'll need a different bracket for a Bosch? And some cunning wiring (don't read that too quickly)?It's typical, I rarely NEED the car these days, and the day I book it in for window tinting - this Tuesday - the bloody thing has a problem.OK - anyone know what straight forward replacement I can source and put on fairly quickly? ;D... and I'd like the moon on a stick too, please? Link to comment Share on other sites More sharing options...
junkuser Posted September 25, 2011 Share Posted September 25, 2011 From your description off light off at idle and on with revs, worn brushes and slip rings could be the cause.Denso alternators are a good, reliable replacement. A bit of fiddling with mountings required. Link to comment Share on other sites More sharing options...
Greeks Posted September 25, 2011 Author Share Posted September 25, 2011 I've just taken the back off to inspect the brushes. Never having done this before I'm not sure what i'm looking at :BIs it normal for the brushes to be different lengths as per photo? Link to comment Share on other sites More sharing options...
piman Posted September 25, 2011 Share Posted September 25, 2011 Hello Greeks, yes, the outer brush is running much faster than the inner (I know the brush is static but you get what I mean?). The important thing is sufficient length to have pressure on the slip rings, if they have then they are OK.AlecPS you should have about 14.5 volts charging. Link to comment Share on other sites More sharing options...
Greeks Posted September 25, 2011 Author Share Posted September 25, 2011 Hi AlecYes, makes sense the outer would wear that much faster. Not sure how I tell if it's making contact though...Only got 13 volts charging, so that's clearly wrong.EDIT: the tippex test shows contact is being made. So I guess that rules the brushes out. Link to comment Share on other sites More sharing options...
piman Posted September 25, 2011 Share Posted September 25, 2011 Hello Greeks, it must have pressure, not just contact? (When I did maintenance on industrial machines we used a spring balance to check brush spring pressure)Alec Link to comment Share on other sites More sharing options...
Greeks Posted September 25, 2011 Author Share Posted September 25, 2011 piman wrote:Hello Greeks, it must have pressure, not just contact? (When I did maintenance on industrial machines we used a spring balance to check brush spring pressure)AlecHmmm, not sure I can figure that out very easily ... and anyway I would have thought brush or spring failure would have been gradual rather than sudden. I'll see what my options are tomorrow, I've no idea how easy / expensive Lucas parts will be here. Link to comment Share on other sites More sharing options...
piman Posted September 25, 2011 Share Posted September 25, 2011 Hello Greeks, judge by the length above the mounting face, brushes are about a fiver I believe? I don't know if there is some scope to pull the brush out a bit to stretch the spring and try again. If it still doesn't charge, forget the brushes it's something else. As I said I wouldn't bother fiddling anymore if it's not the brushes. I've two cars that have 15ACRs with about twenty years running between them and only one alternator failure.Alec Link to comment Share on other sites More sharing options...
Greeks Posted September 25, 2011 Author Share Posted September 25, 2011 I was guessing at 15 ACR ... it's actually 17 ACR being a '78 model of course. The original lasted at least 100,000 km, and this one's only made half that. Sticker shows it's a Lucas boxed http://www.baxters.com.au/ reconditioned model ... all looks nice and new inside, but I guess it's just cheap components >:(To be fair I recall when I bought it it was half the price of all the other Lucas alternators in town, so "you gets what you pay for." Link to comment Share on other sites More sharing options...
Greeks Posted September 25, 2011 Author Share Posted September 25, 2011 Well the first place I called suggested a Lucas NAB 300 is a direct swap and 65A ... as long as you get the right handed one.The web says these are fitted to Range Rover Classics to '94 and Disco / Defender 200tdi models. Link to comment Share on other sites More sharing options...
junkuser Posted September 26, 2011 Share Posted September 26, 2011 The combination of worn brushes (giving decreased pressure) and unevenly worn slip rings can result in the brushes bouncing.This can give charging at low revs but decreased charging at higher. Hence my comment. Link to comment Share on other sites More sharing options...
Greeks Posted September 26, 2011 Author Share Posted September 26, 2011 Ah, I see. Well the slip rings 'look' to be even and in really good condition to be honest. Link to comment Share on other sites More sharing options...
mikeyb Posted September 26, 2011 Share Posted September 26, 2011 Greeks wrote:Well the first place I called suggested a Lucas NAB 300 is a direct swap and 65A ... as long as you get the right handed one.The web says these are fitted to Range Rover Classics to '94 and Disco / Defender 200tdi models.If I recall, that is quite a large unit. They also have an extra diode pack (in star formation?) to run the tacho. Link to comment Share on other sites More sharing options...
Greeks Posted September 26, 2011 Author Share Posted September 26, 2011 Ordered 9am, delivered to my office ~4pm (delivery cost 10 quid).Not bad considering it came 80 miles and the local auto electrics stockists claimed there were no Lucas stockists in Australia now ;DFor the record it's slightly shallower than the 17ACR as it doesn't have the black moulding at the back.Weighs about the same though :(Main thing is it was a straight swap. Link to comment Share on other sites More sharing options...
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