Unfortunately, I fried my alternator in the process, because I initially put the battery in backwards. The famous magic smoke began to escape from the alternator until I noticed it and hastily disconnected the battery. After that initial mistake, I found that the alternator was producing smoke even with the battery installed correctly. Nothing makes you feel stupid quite like destroying a $100 part because you couldn't tell positive from negative.
A little looking around confirms that, yes, the Lucas 17ACR alternator is user-serviceable. I have to say, I love the fact that parts I usually consider disposable are serviceable in this car. I'm no electronics wiz - obviously, given that I put the car battery in backwards! - but I can solder reasonably well, so the steps before me appear to be:
- Remove alternator. Disassemble.
- Test "rectifier" component. The rectifier uses diodes to turn the alternating current produced by the alternator into the direct current needed by the car, according to this nice alternator writeup on The Triumph Experience. It's probably shot, as diodes are components that only allow current to flow in one direction, and that's exactly what wasn't happening here. Those little diodes gave their lives defending the alternator guts - we just don't know if they were successful at it. It's a $15-30 part, depending on which of several variations I get and where I get it from.
- Test the voltage regulator. We're hoping for better news here - it's possible that the regulator is ok. But if not, that's another ~$30 part.
- There's also a voltage stabilizer, which is somehow different from a voltage regulator, and also appears to cost ~$15.
- Inspect the bearings and other parts for signs of wear. Autozone replacements are around $80, and reconditioned Lucas examples seem to sell for $90ish on eBay. So if the thing needs more than a few of those $30 pieces replaced, I'll probably just get a new one. But if not...
- If we decide to go ahead with the rebuild, replace the brushes ($peanuts) and perhaps the drive-end bearings while we're in there, if they look bad.
- Put it all back together and reinstall to see if it worked.
In case you found this blog because you, too, fried your Lucas alternator and need help understanding how to test & fix it, here are some resources for you.
- The aforementioned alternators 101 article on The Triumph Experience
- This how-to about repairing Lucas alternators on the Vintage Triumph Register (VTR) site
- This exploded view diagram of the alternator on the Victoria British parts site
- This rebuild kit how-to article on OldClassicCar.co.uk
- And your Haynes manual, though it goes into more detail about the older generators than it does about the alternators.
Expect to hear a lot more about alternators in the near future. That's all for now!