Alternator Brush replacement, now the alternator squeals!

[ajamunro]

Hey all,

Long time forum reader, first time poster (i think this'll be the first post).

Started getting the blinky christmas lights on my dash last week. Not all the time, but once a day, while idling, usually first thing, or early in the morning when I'm off to work. Typically while the alternator is pulling a fair load, like the head lights, radio, blower on max, and the brakes applied.

The Brake applied seems to be an issue, somehow causing too much drain. I dunno.

The last time I messed with the alternator was about 3 years ago while on a road trip, in California. My wife and I replaced it in a parking lot. We learned a lot that day. So three years of no problems is pretty good for a Toy van i figure.

So i inspected the brushes on the alternator, ordered a new set from Toyota and installed them. I'm still at the visual inspection ability level. Using ohmmeters, or a multi meter, is a bit beyond me for now. I should just buy one and figure it out, just like everything else I've taken on.

I haven't driven the van far yet, so I can't be sure about handling the CHristmas Lights issue, but there is now a squealing sound coming from, i think, the alternator! I have a hard time believing that the bearings are shot. I read on some post Timsrvs (SP?) suggested using emory paper on the copper part that the brushes touch, but I only read that after reintalling everything. Could that the the cause of the squeal?

The squeal occurs, IIRC, when under load and downshifting (i have a manual van), and, when I first started it up after reinstalling the alternator and then turned on all the accessories, including high beams, turn signal, and foot on the brake.

And of course I do have a leaky power steering pump, but it seems that it hasn't been leaking terribly onto the Alt. The Alt. is just fairly clean, not like a brand new one out of the box, but not soaking in ATF.

Perhaps I've got the tension of the Serpentine belt on, too tightly, but I don't that's it. I've hoping that after a day or so, the brushes round their way into good contact with the copper and stop squealing.

Ideas? Concerns? Ideas about the brake light issue? Please comment! I've used this forum as a resource for a while now and am hoping to get some tailor made answers.

Best,
Alex

[ajamunro]

19791980 An old and new shot. You can see from the photo of the old brushes that there is some uneven wear going on. HMMM

[timsrv]

To a trained ear noises like this can often identify the problem in an instant. Descriptions of noises though can be very hard to diagnose. To me squeals typically mean loose and/or worn belts. If it squeals mostly when cold and while down shifting, this sounds to me like a loose belt. If the belt got ATF or oil on it, this can also cause a squeal. Another common problem (unrelated to the alternator) is bad bearings in the idler pulleys. Sometimes these bearings seize and the belt will squeal at times as it skids over the top of it. Only the power steering and AC belts have idler pulleys, but if one of these were loose and you tightened it, this could explain the squeal being new.

The brake lights pull a fair bit of current, so it's not unusual to see charging system issues exasperated when stepping on the brakes. This shouldn't be an issue if your problem has been solved. If you're still getting Christmas lights after replacing the brushes, then there's likely something else wrong. Tim

[ajamunro]

" If the belt got ATF or oil on it, this can also cause a squeal."

It's entirely possible I got some oil gunk on the belt while taking out and reinstalling the Alt. Will that wear off in time, or can/should I clean it? Or should i clean the pulleys and replace the belt?

" Only the power steering and AC belts have idler pulleys, but if one of these were loose and you tightened it, this could explain the squeal being new. "

I haven't mucked about with those before. No AC too, on this van.

"The brake lights pull a fair bit of current, so it's not unusual to see charging system issues exasperated when stepping on the brakes. This shouldn't be an issue if your problem has been solved. If you're still getting Christmas lights after replacing the brushes, then there's likely something else wrong. Tim"

We'll find out tomorrow or perhaps the next few days if the Christmas lights are resolved.

Thanks for the prompt response there Tim.

[timsrv]

It's entirely possible I got some oil gunk on the belt while taking out and reinstalling the Alt. Will that wear off in time, or can/should I clean it? Or should i clean the pulleys and replace the belt?

Once belts are allowed to squeal for any length of time they should be replaced. If the belt was new and only squealed intermittently for a day, then perhaps it could be worth trying to clean and adjust. Belts are cheap though (if you know where to shop) so whenever I have any doubts I just replace. Another thing that can happen (if belts are allowed to squeal excessively) is the pulleys can actually get glazed and this can even cause new belts to slip. I usually deal with pulley glaze by using sand paper or emery cloth. Sometimes scotch bright is enough. I had one once that was so shiny I couldn't get the job done with normal methods. When the vehicle had some down time I took the belt off and brushed battery acid on the belt surface of the pulleys. A couple weeks later the pulleys were nice and abrasive. Worked like a charm but probably not the best way to do it (battery acid can be hazardous). Tim