Seems like the bearings are shot in my alternator... it's intermittent but getting worse. Used to only make noise with a/c on for a bit at startup. Today at startup, it made a ear piercing screeching noise. I quickly turned it off and the Alt pulley was burning hot. The pulley was turning (not seized) but quickly got hot enough to boil water (I spit on it, lol).

Anyway, Looking at a bunch of auto part sites, there seems to be 2 alternators listed for the 99 RX300. A early design with a 65mm pulley(before 7/98) and a second design with a 57mm pulley (after 7/98).
I measured the outer (outmost) edge of my pulley and it's 65mm. I assume that would be the correct place to measure and not the inner part where the belt sits.

Any thoughts on a replacement unit ? Most are remanufactured.
Thanks

 

I don't think alternator bearing failure is all that common, so I would consider a used one from an auto recycler (i.e., junk yard). There are likely different qualities of remanufactured alternators. I think I'd go with either a used junk yard one or a remanufactured one from a discount mail-order Toyota or Lexus dealer. That's just an opinion, not from actual experience.

 

I ordered bearings from Plano TEXAS Lexus. But you know they sell just the bearings. It really isnt that difficult. Replaced mine along with the commutator brushes. Good for another 125k miles hopefully... by the way the front and rear bearing are two different sizes.

 

Thanks for the input.... from this illustration it looks like the same bearing in front & rear ?

http://www.trademotion.com/partlocat...layCatalogid=0

 

My bad, I must have rebuilt something else since and thought they were different. Yep just order the bearings...suggest the brushes too.. take that back, look at the prices of the two bearings. they just used one number for both bearings, but you have to order the front and rear bearing...

 

Thanks....

By the way, how hard is it to remove and replace the bearings ? Are they pressed in ?

Also, after digging deeper at that site and clicking on 3) bearings, they do indeed show a front and rear bearing, so you were right...

Description Year MSRP Price Core Price Your Price
Bearings, rx300, rear 99-03 $23.53 $18.82
Bearings, rx300, front, 100 amp 99-03 $12.70 $10.16

 

The bearings generally stick to the armature of the alternator but are definetly not pressed in. A bearing puller can help remove the bearing off the armature...Getting the alternator out is more difficult than taking it apart. The pivot point always sticks for everyone. needs a nice big screwdriver to pry it out. On a scale of 1 to 10 probably a 3 or 4 in difficulty to perform bearing and brush replacement.

 

Update:
It took me about 10-15 minutes to remove the alternator from the vehicle. However, taking the alternator apart was a nightmare. I would guess 2 or 3 hours, though I was going slow trying to figure out how it comes apart and also not wanting to break anything. The bearings are pressed into the each end of the case. While the inner part of the bearing is sort of pressed onto to each end of the armature shaft. I ended up needing an air impact wrench to remove the pulley nut. A puller was needed to press the case/bearing (with bearing still inside) off the shaft. Then I was able to use a socket & hammer to drive the bearing out of each end of the case. The only casualty was a thin washer that sits between the smaller bearing and the case on the back end. It got mangled driving the bearing out. I am hoping a new one might come with the bearings which are due on Tuesday. If not, I might just chalk this endeavor up to experience and just buy a new unit. The bearings were fairly cheap, so I'm not out that much....

Based on my experience, I would not recommend this route unless you are skilled with lots of experience and have a good assortment of tools at hand.

Luckily, my RX is my bad weather car not a daily driver, so I can do without for a couple days.

 

I am so sorry, I have taken several alternators apart including the RX300 one and did not experience your problems. Maybe there was a lot of corrosion in there as I did not have to do what you did to yours. Next time to remove the case bearing put the rear case in a vise, on top of some cloth and slowly work the armature and bearing out of the case. Also some penentrant may have helped you. By the way my hats of to you for trying, The education you got was well worth the effort and I am sure will save you money in the future knowing that you can do it yourself. I always tell people that learning by your mistakes is money well spent....Good luck

 

The heat did it.

Salim