1989 S4 115 amp alternator rebuild - Need help with parts and procedure
11-02-2011, 01:41 AM
#1
Three Wheelin'
Thread Starter
1989 S4 115 amp alternator rebuild - Need help with parts and procedure
My Alt. spins well, but is not putting out enough voltage and the voltage that it is putting out seems to be trashy and causing havoc with my LH brain.
Does anyone know of any good write-ups on rebuilding the Bosch 115amp alt?
Does anyone know of any good write-ups on rebuilding the Bosch 115amp alt?
11-02-2011, 02:49 AM
#3
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Bill Ball rebuilt his '89 in this thread:
https://rennlist.com/forums/928-foru...tor-parts.html
Including links to parts vendors and a DIY rebuild of a Bosch alternator from some Range Rover site.
This is timely, as the original alternator in my '93 is not real happy, I'm having to put the car on the trickle charger between drives and my current draw at rest is only 27 mA, so I've been thinking about rebuilding mine too.
Alternator trivia: 928Intl lists the same rebuilt alternator for '85 to '95, while PET lists '85-89 as 928 603 011 01 and 90-95 as 928 603 011 05. So I'd imagine that many if not all parts are the same for your '89, but don't quote me on that.
There are more than one voltage regulator for these alternators, which differ in the value of some resistor that seems to have something to do with the temperature/climate the alternator will see. Wagner lists a 68 ohm unit for colder weather, while all the WAI units are 120 ohm. PET lists the 85-95 928 regulator as 928 603 142 00 (which I think is Bosch # 1 197 311 021), no idea what its ohm rating is. Rock Auto has them for $29, but I'd be slightly paranoid about their pedigree.
Anyway, here are the Wagner and cross-referenced WAI parts numbers for the 928 603 011 05 '90-95 Alternator (Bosch 0 120 468 005), compiled from the 2010 Wagner master catalog (http://www.wagneralt.com/catalog/books/w2010-1.pdf) and WAI's parts # lookup (http://www.waiglobal.com/partsearch.html) You should be able to compile a similar list for an '89, which I think is a Bosch 0 120 468 004.
So- Bill mentions that he used http://www.nationsautoelectric.com/altparts.html to buy parts using the WAI part #'s, while Donald was able to buy direct from Wagner.
https://rennlist.com/forums/928-foru...tor-parts.html
Including links to parts vendors and a DIY rebuild of a Bosch alternator from some Range Rover site.
This is timely, as the original alternator in my '93 is not real happy, I'm having to put the car on the trickle charger between drives and my current draw at rest is only 27 mA, so I've been thinking about rebuilding mine too.
Alternator trivia: 928Intl lists the same rebuilt alternator for '85 to '95, while PET lists '85-89 as 928 603 011 01 and 90-95 as 928 603 011 05. So I'd imagine that many if not all parts are the same for your '89, but don't quote me on that.
There are more than one voltage regulator for these alternators, which differ in the value of some resistor that seems to have something to do with the temperature/climate the alternator will see. Wagner lists a 68 ohm unit for colder weather, while all the WAI units are 120 ohm. PET lists the 85-95 928 regulator as 928 603 142 00 (which I think is Bosch # 1 197 311 021), no idea what its ohm rating is. Rock Auto has them for $29, but I'd be slightly paranoid about their pedigree.
Anyway, here are the Wagner and cross-referenced WAI parts numbers for the 928 603 011 05 '90-95 Alternator (Bosch 0 120 468 005), compiled from the 2010 Wagner master catalog (http://www.wagneralt.com/catalog/books/w2010-1.pdf) and WAI's parts # lookup (http://www.waiglobal.com/partsearch.html) You should be able to compile a similar list for an '89, which I think is a Bosch 0 120 468 004.
Code:
928 603 011 05 - 1990-95 Alternator Bosch P/N 0-120-468-005 Wagner # WAI part # 6201 2RS BEARING-12x32x10mm W02X-01 6-201-4 6303 2RS BEARING-17x47x14mm W02X-11 6-303-4 Bosch alternator brush, 4.9 x 7.9 x 19 mm length, 60 mm LL. 12V, for 28 mm slip ring, insulated W030-02 38-9100 Rectifier 120 mm OD, 8mm B+ post, 5 mmD+ post, 1/4" B+ Spade 14-35 A diodes, with diode trio, 15 amp units, diodes W04X-28, W04X-29 W04X-01 W060-52 Regulator and brush holder, 14.5V, A-circuit, with 68 ohm resistor for cold zones, low profile W080-05 IB354, IB 355, IB356 (all 120 ohm resistor) Bosch noise suppressor, 2.2uF, used on most bosch alternators W110-04 46-91100 Assortment of pulley hardware, W110-50 spacer, W110-44 wooduff key, W110-29 nut, W110-22 nut W110-06N Bosch plastic bearing retainer, 32mm ID x 35 mm OD x 12.9mm W. Used with 6201 bearing (W02X-01) W110-21 46-91550 Bakelite, 115A units W110-43 Bosch slip ring, 28 mm , 17 mm ID, 28 mm OD, ER/EF, IR/EF. W160-01 28-91850-1 40 mm bolt pattern, 4 mm threads, fits 6303 bearing, external fan and some internal fan applications W110-58 Paris Rhone bearing retainer 32 mm ID x 34 mm OD x 14 mm W, Fits W02X-01 bearing 6201 W012-02 46-94407
So- Bill mentions that he used http://www.nationsautoelectric.com/altparts.html to buy parts using the WAI part #'s, while Donald was able to buy direct from Wagner.
11-02-2011, 04:14 AM
#4
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Also, replacing the slip ring looked a bit tricky and is not covered in the Bosch procedure I linked in that earlier thread. If the wear is not too bad, you can machine off the high spots. That's what I did, mounting the rotor in a buddy's lathe.
11-02-2011, 08:56 AM
#5
Three Wheelin'
Has anyone tried installing an adjustable voltage regulator during their rebuild? My alternator is in the shop right now for a rebuild (noisy bearing) and after I asked the owner if there's anything that he could do to boost the voltage output he recommended that I install one of these. I agreed and I'm waiting for the part to come from the US (about 1 week). He said he's done it for the Bimmer guys and usually adjust them to 14.5V.
11-02-2011, 09:56 AM
#6
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Overcharging can cook a battery / boil the water out.
14.5 volts seems excessive to me but if this guy will warranty the work ...
I would try to get 13.5 volts on the post with all accessories on. Maybe that is 14.5 volts with no load ?
14.5 volts seems excessive to me but if this guy will warranty the work ...
I would try to get 13.5 volts on the post with all accessories on. Maybe that is 14.5 volts with no load ?
11-02-2011, 10:02 AM
#7
Nordschleife Master
I wonder if we're talking different things. I popped one of these into my Bosch alternator and it worked great. It'll be the new brushes that you need, 9 times out of 10.
Takes 2 minutes after getting the alternator out.
http://www.drivewire.com/ voltage regulators
Or go to http://www.drivewire.com/ and search.
Takes 2 minutes after getting the alternator out.
http://www.drivewire.com/ voltage regulators
Or go to http://www.drivewire.com/ and search.
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11-02-2011, 11:47 AM
#8
Three Wheelin'
Thread Starter
Great info thanks guys!
@ Fred D, let me know how this works for you. that rig looks interesting.
@ Glen L, Which reg. did you buy and how is it working for you so far?
@ Bill Ball, The slip ring you refered to could also be called a commutator if it is what the brushes ride on. In any case it would be tricky to replace. I think you were wise to simply true it up.
@ Fred D, let me know how this works for you. that rig looks interesting.
@ Glen L, Which reg. did you buy and how is it working for you so far?
@ Bill Ball, The slip ring you refered to could also be called a commutator if it is what the brushes ride on. In any case it would be tricky to replace. I think you were wise to simply true it up.
11-02-2011, 12:40 PM
#9
Three Wheelin'
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Curtis:
welcome back- I just rebuilt a spare alternator using the link in Bill's linked post, and replaced the slip rings as well. They were way too far gone for just a shave. It was not that hard getting them off and on, BUT: I have not been able to test the results as I do not have a spare pulley.
welcome back- I just rebuilt a spare alternator using the link in Bill's linked post, and replaced the slip rings as well. They were way too far gone for just a shave. It was not that hard getting them off and on, BUT: I have not been able to test the results as I do not have a spare pulley.
11-02-2011, 01:06 PM
#10
Nordschleife Master
I forget! I got the one for the Bosch alternator I have in my car. That alternator is actually for an Audi but bolts up fine except for the shroud. The FLAPS had it on the shelf on a Sunday so I've been happy.
I just looked according to year and model for your car.
I just looked according to year and model for your car.
11-02-2011, 01:27 PM
#11
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Has anyone tried installing an adjustable voltage regulator during their rebuild? My alternator is in the shop right now for a rebuild (noisy bearing) and after I asked the owner if there's anything that he could do to boost the voltage output he recommended that I install one of these. I agreed and I'm waiting for the part to come from the US (about 1 week). He said he's done it for the Bimmer guys and usually adjust them to 14.5V.
Attachment 579395
Attachment 579396
Attachment 579395
Attachment 579396
11-02-2011, 02:00 PM
#12
Three Wheelin'
Thread Starter
@ Donald, did you take any pics of your slip ring replacement 
How does the slip ring/commutator make contact with the windings?
@ Glen L, both the HELLA and the KAEHLER voltage regulator are direct replacements and look differant than the ones listed by Bill (http://www.wagneralt.com/visions/default.asp).
Just wondering out loud as to who has had the best luck with which regulator?
@ Bill, 500 watts and no capacitor to buffer the power surge.
Didn't Porsche change the diameter of the crank pulley at some point to spin the alt faster? ~90GT?
EDIT: Ok I had an extra min. to look it up.
Service
Information
Technik
'90
Alternator - 928 S4
The alternator speed level Is increased by selecting a higher ratio to improve power supply in 928 84 cars.
The diameter of the crankshaft pulley is Increased from 134.9 mm to 142.8 mm, which changes the ratio from 2 .65 : 1 to 2 .80 : 1 .
A new poly-rib drive belt (872 mm) must also be installed for this reason (928 GT: 858 mm) . Maximum alternator speed is increased to 18,480 rpm . The alternator's fan wheel had to be changed
to a diecast product to make it strong enough for high speed operation .A higher ratio for the engine in 928 GT cars is not possible because of the higher maximum engine
speed.
How does the slip ring/commutator make contact with the windings?@ Glen L, both the HELLA and the KAEHLER voltage regulator are direct replacements and look differant than the ones listed by Bill (http://www.wagneralt.com/visions/default.asp).
Just wondering out loud as to who has had the best luck with which regulator?
@ Bill, 500 watts and no capacitor to buffer the power surge.
Didn't Porsche change the diameter of the crank pulley at some point to spin the alt faster? ~90GT?
EDIT: Ok I had an extra min. to look it up.
Service
Information
Technik
'90
Alternator - 928 S4
The alternator speed level Is increased by selecting a higher ratio to improve power supply in 928 84 cars.
The diameter of the crankshaft pulley is Increased from 134.9 mm to 142.8 mm, which changes the ratio from 2 .65 : 1 to 2 .80 : 1 .
A new poly-rib drive belt (872 mm) must also be installed for this reason (928 GT: 858 mm) . Maximum alternator speed is increased to 18,480 rpm . The alternator's fan wheel had to be changed
to a diecast product to make it strong enough for high speed operation .A higher ratio for the engine in 928 GT cars is not possible because of the higher maximum engine
speed.
Last edited by T_MaX; 11-02-2011 at 02:16 PM.
11-02-2011, 07:14 PM
#15
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Nice, Donald.
So, what type of solder did you use? Also, it looks like the solid wire broke off. I was fearing that so turned the ring instead believing it still had enough meat left, although mine was worn at least as much as yours. Did the wire break? How did you fix that?
I see you got your stuff directly from E. Wagner himself!
So, what type of solder did you use? Also, it looks like the solid wire broke off. I was fearing that so turned the ring instead believing it still had enough meat left, although mine was worn at least as much as yours. Did the wire break? How did you fix that?
I see you got your stuff directly from E. Wagner himself!