A common fault

The Sprint I have just got had a really horrible ringing rattle towards the rear of the engine, it seemed to ease up if the lights were switched on, this apparently is a common fault with the alternator drive impeller.

To inspect this I had to remove the alternator, first off was the left hand side coolant hose cover then the electrical conneting block had to be disconnected and the three mounting bolts undone...all was well until I met these little buggers...thankfully Roden and a few others on the Triumphrat.net forum had attacked these previously so I had a good idea what to do about them.

The heads of the bolts rust to the alternator..the threads are no problem just the heads, the anwser is to give them a good whack with an impact driver before straining and sweating trying to undo them..



Now at last we get to the root cause of the problem..you can just see a tiny gap under the nut head that holds the impeller on, the nut itself is not loose as this has thread lock on it but it has worked it's way out enough for the impeller to be loose..to remove the nut you'll need to hold the impeller with some mole grips as pictured





unfortunatley for me too much wear had occured on the impeller splines to be able to just bolt the thing back up. so I ordered a new impeller and just for good measure some new cush drive rubbers too. after having a bit of a read up a cure for the loose nut is to drill and tap it out to take an M8 nut...this I set about doing.

I first made up a little stand for the alternator so it would be level when I drilled it, then I masked it up to stop all the metal bits getting into the workings...







I used some strong thread lock on the M8 nut and the impeller splines and I hope that will do the job..



I also took a wire brush to the alternator, as with soo much of the Sprint it had suffered in the winters and had lived outside for most of it's life too, I gave it a lick of hammerite and replaced all the fixings for stainless.

It all went back together fine..I had to use blobs of grease on the cush drive rubbers to get them to stay in place, wipe some fresh oil around the O ring and remember to attach the earth ring and block connector.