Alternator Issues, Bearings? Options

[Britain Smith]

I replaced my alternator a couple of weeks ago because the bearing went out and it was make an horrible grinding sound. I used a Bosch unit from HPH and everything went fine. Yesterday, I was driving around town and when I came to my desitination I heard a very similar grinding sound coming from the front of the engine. About 15mins later I started the car back up, the sound was still there but not as loud and now the red alternator light was on. Then, after work I was driving the car home and the sound was not that obvious but the light was going on and off and a bit dim at times. When I got home, I opened the engine lid and could hear the alternator spinning as it sounded like it was dragging or something. When I turn the car off you can hear it grinding a bit after all the other noises stop.

Has anyone had any issues with the bearings going bad in freshly rebuilt Bosch alternators? Any other ideas? The belt is tight and everything else looks good. I really don't want to have to go through replacing the alternator again...it looks like I will be though. What is the best way to test the alternator both inside and outside the car?

-Britain

[nebreitling]

weird. was it aligned with the fan well?

i've got an old alternator around here you can use if you need.

[Britain Smith]

How can it be out of alignment with the fan? Everything fits in the only one way doesn't it?

I am going to run by HPH today and pick up a new unit.

-Britain

[nebreitling]

you're right, i was thinking about something else. (IMG:http://www.914world.com/bbs2/html/emoticons/sad.gif)

[Dave_Darling]

The mounting bracket usually has a bit of slop in its position, so you can misalign it slightly. Mine kept throwing belts until I went back in and fussed with the bracket.

No idea on why the new one would fail. Did you hook up the cooling air boot?

(If you've got a digital camera, I'd be grateful if you took pics as you went. I'd love to have some pics we can put up with my article on the Bird site.)

--DD

[McMark]

Overtightening the belt can wear bearings, but a week is still really odd. Could be a defect unit. It happens.

[Britain Smith]

QUOTE (McMark @ Apr 20 2005, 12:33 PM)

Overtightening the belt can wear bearings, but a week is still really odd. Could be a defect unit. It happens.

It was probably closer to a month or so. How do you determine if it was overtightened? How tight should it be?

-Britain

[McMark]

Consider that you just need it tight enough to provide the necessary friction to turn the alternator. I think there are specs in the books, but 1/2" deflection seems about right. Probably looser than you expect.

[Britain Smith]

QUOTE (McMark @ Apr 20 2005, 01:19 PM)

Consider that you just need it tight enough to provide the necessary friction to turn the alternator. I think there are specs in the books, but 1/2" deflection seems about right. Probably looser than you expect.

Yea, that is probably about how much I had on there. Both Brad and Rich said it felt good.

-Britain

[TheCabinetmaker]

You bought a rebuilt unit, but was it rebuilt by Bosch? If not, then yes, the bearing could go bad that quick if built by an independent rebuilder. They do hundreds at a time and don't replace everything. They replace only whats necessary to make the unit work. At a month old, it should be under full warranty.

[Britain Smith]

QUOTE (vsg914 @ Apr 20 2005, 02:27 PM)

You bought a rebuilt unit, but was it rebuilt by Bosch? If not, then yes, the bearing could go bad that quick if built by an independent rebuilder. They do hundreds at a time and don't replace everything. They replace only whats necessary to make the unit work. At a month old, it should be under full warranty.

It was rebuilt by Bosch and yes it is under warrenty. I already picked up a replacement from HPH.

-Britain