alternator problems 90 camry

[omiimiish]

Hi my 90 camry wagon has the "battery", "brake", "lights" warning lights coming on and I am losing power. It seems obvious at first. I checked the battery, fully charged it, it seemed to hold decent under load. I did an alternator check and it is putting out 12.5 volts running no accessories. I am assuming that this is low output?

Any suggestions?
dave

[zppeacock]

yes alternator should be putting out some where between 13 and 14

[Doctor J]

Measure voltage between the ground and B [battery terminal] of the alternator. If still low
remove the alternator
take off the back cover
remove
brushes
regulator
diode bridge
check diodes
brushes
if both are good try another voltage regulator.

[TBayToyotaBoy]

Wow, Doc, that's a thorough suggestion! Every...single...time I've had problems, it has been the voltage regulator. If you're inexperienced and nervous about cracking an alternator apart in such detail, it might not hurt to go straight for the regulator and replace it. If it doesn't help your current troubles, I can guarantee it will prevent future problems.

Here is the back of the alternator (cover off) with the reg still attached:



And here is the regulator removed (four tiny screws hold it on):

[blkdmnrcing]

wow that is cool. i just had a scare with mine last night. my radio has voltage display. at idle at a red light it was down to 11.8v, then when i took off it would only get up to 13.5v. i shut the car of and started it back up and it was charging at 14.2v. think its the requlator? or battery going up?

[Doctor J]

Probably diodes or brushes [the latter can cause flickering charge light].

[slow rider]

Good pictures. The brushes are in that orange rubber covered part that fits over the centre spindle of the alternator. My charge light was on, so I removed the alternator and took those parts in the picture off, there were 5 screws holding it all on. The brushes were only just long enough to make contact with the spindle slip rings. The slip rings themselves were black from carbon brush material on them. This was the cause of the problem, I cleaned them with a pencil eraser and then polished them with the finest emery cloth I had and put it all back together. The charge light no longer stays on. I will have to get a replacement alternator soon because one of the slip rings was worn down about 1-2 mm and the brushes were a bit short, but it fixed it for now, which buys me some time to find another less worn alternator. If the slip rings were not worn down I could have just bought new brushes and holder which I have seen for sale in e-bay shops. Cheers.