Alternator Bearing

[BAHNW]

1998 Bayliner 2355 with 5.7 litre Mercruiser and Alpha I. Does anyone know if the alternator bearing can be replaced? It makes a bit of a squeek at idle that dissipates as the RPM are increased. I took off the belt and spun the alternator by hand and it is definetly the culprit. Altenrator is charging fine but I certainly don't want to be out on the sound when the bearing totally fails.<br /><br />If it can be replaced is it the sort of thing that I can do or does it need to be pressure fitted on?

 

[Silvertip]

Re: Alternator Bearing

Yes -- check the yellow pages for auto-electric (starter/generator/alternator rebuilders). Its a relatively inexpensive fix. Or, if its a GM alternator, you can buy the bearing at NAPA. Replace the back one as well and while you are in there, have the brushes replaced and you'll have an almost "rebuilt" alternator.

 

[BAHNW]

Re: Alternator Bearing

If it is in fact GM can I replace the bearing myself or is there special tools involved?<br /><br />Thanks

 

[LubeDude]

Re: Alternator Bearing

I havnt been into the new ones, but the older single wire alternators are a cinch. Pull the pully. and the long small bolts holding the case together, pull the front cover off and you are in. If its like the one I just did, there are three screws holing the bearing in. Take them out and the bearing will come out. Take it to NAPA and get a new one. Now the rear bearing is harder because you have to pull the winding assy out and the brushes will pop out they can be a bear to get back in. The brushes are probably good though. The rear bearing is a needle type and Im not sure what lube is recommended there. I just put a couple drops of gear oil on them and a dab of moly grease with a Q-tip. So far so good.

 

[Silvertip]

Re: Alternator Bearing

Brushes on an older GM alternator are easy to hold in place using a small finish nail or piece of wire slid through the provided hole. Assemble the unit, then pull the pins. The rear bearing is simply driven out but be sure to block the casting carefully to prevent breaking it. Use a wood dowel to drive it out. Drive in the new one using a block of wood.