Alternator Bearing Refresh

[320iAman]

My alternator got noisy, after inspection found it was the front bearing, changed both out big/small bearings and used SKF bearings, made in France.


Pulled the small BearingDSCI0369.JPG Removed the front BearingDSCI0370.JPG SKF Bearings~$10 for bothDSCI0373.JPG
Put back togetherDSCI0375.JPG

DSCI0374.JPG Note the closeness of the Rotor to the Stator,, this is an Higher Amp Alternator 80A,,in stock 65Amp Alternators the distance between the Rotor and the Stator is greater--For these in E21 Alternator Cases, more or bigger wire has advantages.

I'm running my 100Amp Alternator presently and plan to rebuild the 65A one I have.....--The 65 Amp alternator is being rebuilt now---pictures later and a new thread as all the parts come in and the rebuild process is done step by step-this is a larger refresh....


Randy

[320iAman]

Here is a comparison of the 65 Amp Stator with the 80 Amp Stator

DSCI0380.JPG 65A Stator DSCI0381.JPG 80A Stator

There is more air space in the 65A Stator Windings than in the 80A Stator Windings , more loops equals Higher Output Stator in this case.


Randy

[320iAman]

Installed new Alternator Bushings, The bushings are replacements for BMW numbers 12311268435 and 1311268433. This 80A alternator got new bearings and bushings and will get the new pulley thats inbound and new EF paint.

DSCI0389.JPG

Randy

[goodkarmech]

Great write up and good to know the part numbers for the bearings. Thanks!

[320iAman]

Sure, no point in buying an bosch alternator AL44x for $160 + for a wore out bearing, when for $10 both can be replaced with top quality bearings, SKF is the largest bearing manufacturer in the world,,tend to be pricey--yet deals do exist. I bought 3 sets of SKF Explorer Bearings for $30,, seller recently doubled his price,, other sellers have not.

Pulley came in so both 80 and 65 amp alternators are good to go. I'm running a 100 Amp alternator now and have an SKF Explorer bearing set + new mount bushing(inbound)--for that day.
Those red bottom pivot bushings are Hard Urethane ~ 90 Shore or more ,had to drive them in with an Engineers Hammer---2 1/2 lb , small sledge hammer with a large socket, shop press or large vise
would work too.

DSCI0391.JPG

Randy

[82Kashmir]

Did you ever put together a rebuild parts list: diodes,bearings, slip rings Ect... for the Bosch AL44x ? My alternator is putting out around 13.4 after a new regulator install, under load of lights and fan on high drops to just under 13vdc, with the ac on drops to 11.8vdc. I think I have a bad diode, time to replace or rebuild. Still driving it as is.

[320iAman]

Did you ever put together a rebuild parts list: diodes,bearings, slip rings Ect... for the Bosch AL44x ? My alternator is putting out around 13.4 after a new regulator install, under load of lights and fan on high drops to just under 13vdc, with the ac on drops to 11.8vdc. I think I have a bad diode, time to replace or rebuild. Still driving it as is.

Yes its in another post here:

Bosch 65 Amp Alternator Rebuild

https://www.bimmerforums.com/forum/s...rnator-Rebuild

Randy

[82Kashmir]

Thanks great work and info. For me it may not be worth the price/time to rebuild with parts and shipping costs on all the small parts and assemblies. Rockauto has a reman for $58 +18 core. I would probably keep old alt as a back up for 18 bucks.