Does anybody know where to get a Lucas alternator rebuild kit?

I have an '85 SIII XJ6 and the Lucas alternator went out yesterday. I spent last late evening checking/troubleshooting before diving in to replace it with a good used one from a donor engine. It has unknown miles, so I want to rebuild my Lucas that went out. Interestingly, the battery light never came on, it just stopped charging. The light is good, the exciter wire had good voltage, and the light would come on with grounding the exciter wire, so the alternator problem is yet to be determined. After the PITA job of replacing it, everything is as it should be. The battery light comes on with the ignition ‘on’, and goes out on startup, with positive charging on the gauge. I have looked on the 'net for a rebuild kit, but I have not been able to find one, and no, I don’t want to replace it with a Delco or Denso one, or any other brand.

Then why do you consider a rebuild, Kassaq…?

xj6 85 Sov Europe (UK/NZ)

I didn’t get a kit as such. Bearings to sample from a bearing shop. Brushes from an auto electrician - many models use same. Skimmed up the slip rings - the “end on” to the shaft type. Running the existing regulator
did note these were on eBay at the time. As you couldn’t find a comprehensive kit. far so good. Paul.

Hi Frank, I am wanting to rebuild/refurbish my original alternator so that I have a good one to use if the donor engine one packs it in. I don’t know how many miles are on the donor unit.

Paul, I will see about sourcing a couple new bearings locally, and as soon as I have the unit apart, I can get an idea of what else needs replacement. I will replace the brushes of course, and hope that the diode unit is good. I didn’t notice any problems with the charging voltage when it was working earlier this week, other than it simply stopping its charging one morning. I imagine my regulator is also working okay.


if you really still have that original Lucas alternator on your car it is easy to find out the Lucas pt. no. and from there on the necessary set of brushes and regulator. When mine (i.e. only the regulator) went out on me I got myself a cheap replacement part (now in the car for two years without any troubles), but kept the original one and got a NOS regulator and brushes to finally engage in an overhaul exercise.

You might have a Lucas 25 ACR in your car. There’s the rectifier diode pack
On a typical supplier’s website all you need is offered on one page[15827]&subSectionIds=[17663]. True, the bearings are not in, but they rarely seem to fail.

Good luck and keep us posted … I still need to dive into :slight_smile:


75 XJ6L 4.2 auto

Hi Jochen, this is good information, thanks. Tom is the guy with the problem at hand. Mine is running well and has been for four years since rebuild. The other thing I have done in the past is resweat the solder joints on diode packs - have had to recondition in the past due dry joints. Paul.

I checked the numbers stamped on my alternator. They are: 24101B and: A133. I found a voltage regulator for about $15. I am wondering if it could be some other part in the alternator though. I checked my recently deceased unit with a multimeter. There is a near dead short between the exciter spade contact and the 12v heavy lead. The good/working unit does not have any continuity between those leads. Which internal part would ‘short’…diode, regulator?? The brushes looked good and I didn’t see any obviously broken/shorting wires. Thanks for the links! Tom

Power diodes can fail as a short or open. I guess you could unsweat each at the central tail and test forwards and backwards? Paul.

Sorry Paul,

must have misunderstood your answering post …

Enjoy the week end


75 XJ6L 4.2 auto (UK spec)

All good Jochen! About to take the good lady wife down to the Southern Highlands - about 90mins from home - In the XJ. We’re allowed to travel to regional areas now. Paul.

That’s what you get for tempting fate. Driving around in the Southern Highlands today I noticed gauges reading too high. Got back to our my sister’s and checked the charge: up over 16V at 2500rpm, pulled back to about 14 when the headlights on. Some sort of regulation problem. Kept in check on the way home with headlights and heater fan. In the market for a new regulator. Will have a look at Jochen’s websites now! Paul.

Another reason I’m glad to be living in Southern California. One night several years ago, on my 1986 (Built in July 1985) XJ6, gauge showed charging rate close to 16. On the advice of a fellow lister, I immediately turned on a/c & lights, which brought it down to 13. I asked my local mechanic what to do, he said he deals with a shop which rebuilds alternators of all brands. He had no problem finding a rebuilt replacement, told me to bring my car in, and he’d return my defective unit to the rebuilders after installing the newly rebuilt replacement. Price was very reasonable, included an unconditional one year warranty. That was four years ago, and all is working as it should .

Just for convenience, if nothing else, I might do the same and then set about repairing the old one as a spare. Paul.

Jags are definitely cheaper to drive by the dozen. I found yet another Lucas good spare alternator in my storage shed…So I now have a spare for my current running spare if needed.

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