Rick the Spud Posted May 13, 2009 Share Posted May 13, 2009 Hi all going on a recent 4x4 excursion, started my disco as normal, went scrabbling round in the usual fashion, stalled after about 1.5 hours, and the battery was too dead to restart! from then on, had to get a tow start everytime i stalled. got home, checked leads, nothing obvious, charged battery, started up, all fine. suspect - alternator. now, as far as voltmeter values go: engine off - 12.70 volts engine on - 12.80 v turn on heated window, lights, blower - slowly drops to 12.30v, but no lower turn off all electric things - slowly climbs to 12.70v engine off - 12.7v ish. obviously a good alternator should be pushing 13.5V+, so what's going on here? is it half knackered? i thought dead was dead! any ideas? Rick Quote Link to comment Share on other sites More sharing options...
disco_al Posted May 13, 2009 Share Posted May 13, 2009 possibly brushes have worn down. new brush pack should cure it. take it to an auto electrical specialist, should be able to rebuild it in less than a day, for much less than the cost of a new/recon one Quote Link to comment Share on other sites More sharing options...
Rick the Spud Posted May 13, 2009 Author Share Posted May 13, 2009 so it is still charging - just only a bit? Quote Link to comment Share on other sites More sharing options...
Davecrx Posted May 14, 2009 Share Posted May 14, 2009 yes and no. An alternator should be putting out about 14v Quote Link to comment Share on other sites More sharing options...
drkwack Posted May 14, 2009 Share Posted May 14, 2009 Hi, when I've been off roading especially in muddy water when I get home I usually put hoes pipe close enough to run water thro the alternator while engine is running then wd it to death flushes most of the crapout and wd flushes water away. Quote Link to comment Share on other sites More sharing options...
Rick the Spud Posted May 16, 2009 Author Share Posted May 16, 2009 someone said something about the light on the dash (which never comes on) being a factor? Quote Link to comment Share on other sites More sharing options...
errol209 Posted May 16, 2009 Share Posted May 16, 2009 someone said something about the light on the dash (which never comes on) being a factor? The alternator warning light sits between the ignition live feed and the output of the alternator. It lights up when one side of the circuit goes to a low voltage. In theory, if you could keep the alternator spinning and turn the ignition off it would light up, but more normally it comes on when the alternator stops with the ignition on (e.g. the alternator belt has broken). If it doesn't EVER come on, the bulb has gone. If it comes on just before you trun the engine over, goes out when you start it and stays out, then the alterantor is doing something, but 12.8V is a bit low, 14.0 to 14.4V is much more normal. Quote Link to comment Share on other sites More sharing options...
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