Battery light coming on, battery or alternator?

[dderolph]

Yesterday and today, my battery light came on. It stayed on while I drove for about 10 miles today, later went off, and has been intermittently going on and off. I haven't noticed sluggishness in the starter cranking. Still, I'm wondering whether this is a sign of a battery problem or the alternator going bad.

[jeffcoslacker]

The light rarely if ever reacts to a battery problem (shorted cell being the exception, and then it wouldn't start).

Your charging system is having a problem. Check it with a voltmeter. Could even be overcharging, which will ruin the battery. Get it tested.

[AccordCodger]

Most likely a dying alternator.

[mpumas]

Slip ring brushes in the alternator. Best to get a rebuit alternator.

[dderolph]

Thanks for the replies. I drove the car somewhere Monday (11/6) evening. On the way home, the alternator failed. I was about 5 or 6 miles from home when the lights went dim, and the speedometer and tachometer needles dropped to zero. I actually drove part of the way home with headlights turned off, and I barely made it home. The car acted like it was going to stall any moment in the last mile or so.

I picked up a re-manufactured alternator. The decision to do this myself may have been a mistake. I'm having some difficulty figuring out how to remove the old alternator. I removed the bolts holding the power steering pump and moved it out of the way to make removal of the alternator easier.

I have loosened the top bolt of the alternator. The bottom mounting of the alternator is the problem. I can't clearly see how the bottom assembly comes apart. I'm thinking the belt tension adjusting/sliding bolt needs to be removed. I have removed the nut on the main lower bolt, but I don't know how that bolt comes out. It's different from the top mounting bolt, where the left side of the mounting bracket that holds the alternator is threaded and that bolt can simply be unscrewed and pulled out to the right.

On the bottom, a long nut fits on the end of the mounting bolt. I removed the nut, but I don't know how to remove the bolt so that the alternator can be removed. Do I need to somehow push it through the bolt holes and push it all the way out to the left? It seems like I would need to tap on the right end of that bolt with a hammer or something, but there's not enough open space to get to it with a hammer.

If anyone is familiar with this procedure, please advise me on how that lower alternator mounting is disconnected?

[mpumas]

You don't tell us what year your car is so I can only guess it might be early nineties. I think the bottom bolt is unique in that it has a nut and is also threaded into the bracket. So it acts like a lock nut. After you get the nut off, you need to unscrew the bolt from the bracket. When putting it back together, be careful about the belt tightening. Too tight will take out the rebuilt alternator bearings.

[dderolph]

Thanks again for the reply. The car is a 91 Accord LX, 4-dr sedan. I don't believe the lower bolt is threaded into the bracket on the left end of the bolt. That end has no bolt head for a wrench; it appears to be just a flat end. The bolt also appears to just go through a slot that allows rotation of the alternator for adjusting belt tension. So, the upper bolt, which is threaded into the bracket at the left side of the alternator, acts as a pivot point, while the lower bolt resides in that slot. Perhaps the bolt is just frozen and needs some prying but it's quite difficult to work with, due to tight space.

[dderolph]

A follow up. Indeed, the only threading on the lower bolt is at the end where the nut goes on. I finally got that bolt out. The basic problem was some rust keeping it from coming free. Once I put some WD40 on it and did some prying, it finally came lose. I've had this car for about 9 years and have never replaced the alternator. Perhaps it's the original. Anyway, this has been quite an ordeal but I finally got the old alternator dismounted.