Jaguar XKE Type Workshop


Rebuilding the Lucas 11AC Alternator

Lucas 11AC Alternator Rebuilt Rebuilding the alternator was a bit of fun. I did it for my classic Jaguar, but Lucas electrical components were used in a variety of other cars of that era as well.

Despite all the precautions, I inadvertently reversed the battery connections. This burned out the diodes in the alternator and killed the alternator controller.

Rebuilding an alternator is much the same process for any alternator. Take apart the alternator. Check and replace the components such as brushes, bearings, diodes, stator and alternator controller. Then put it all back together replacing warn or defective components.

Of course, this depends on your skill level and your ability to get the right alternator parts. Parts can be found online, at auto parts suppliers, or specialty shops that specialize in the various components (electrical, bearings, or alternator kits). You should have some experience working on engines as well as be proficient at getting things apart that have been stuck together after a long period of time. These are the kind of techniques you get working on rusty old cars and boats after a while.

An understanding of electricity and electrical components is equally important. Using your voltimeter/ohm meter to measure resistance and continuity of electrical components and check electrial connections is essential to diagnose and identify problems. A bit of soldering may also be required to connect the alternator diodes.


Rebuilding the Lucas 11AC Alternator (cont'd)

Lucas 11AC Alternator Rebuilt I had The Complete Official Jaguar E Workshop Manual by Robert Bentley, Inc. It contained enough specifications and procedures to be able to check the alternator components. Note that in the version I had, the Series 2 Jaguar E-Type sections seemed to be added on as an addendum so some additional research was required.

For example, the alternator specified in the workshop manual indicated my alternator was a Lucas Model 11AC which put out 43 AMPS. However, after discussing my electrical system with one of the Jaguar parts suppliers, there may have been an option for an alternator that had more power for my car since I had a later model with AC. I think it may have been a bit over 60 AMPS.

Rebuilding the Lucas 11AC Alternator (cont'd)

Lucas 11AC Alternator Rebuilt The Jaguar E-Type workshop manual provides procedures, specifications, and tolerances for checking the various alternator components. The stator windings are checked to make sure they are insulated. The stator windings are soldered to the diodes. The diodes a pressed into the metal plate that form the heat sink assembly. If the diodes are bad, they can be pressed out and replaced, although the manual says otherwise. Note one side of the assembly is positive, and the other side is negative.

The brushes are checked for length. If they are not long enough, they can be replaced. The bearings are also easy enough to replace. I purchased the bearings at a local bearing shop.

Although not in the alternator, the alternator controller must also be checked. The procedure is in Bentley's The Complete Official Jaguar E workshop manual

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