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Clutched alternator pulley upgrade on AAZ
by
neimis
on 10 Feb, 2010 02:01
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I recently upgraded the stock alternator pulley on my AAZ to the “clutched” or “freewheeling” type, and thought that some of the information I learned may be useful to others. I know this has been covered in other posts, but there are some details not previously covered that I learned along the way.
First of all, according to my research, there are two sizes (diameters) of pulleys.
Part # 038 903 119A, or it’s superceded part# 022 903 119C, or various other #’s, is for A4 and later vehicles (1999+). Size is 61.5 mm. O.D. It is too big for the AAZ. If you need one for your A4 TDI, best price I found was on eBay for $42 US (INA brand).
Part# 028 903 119AA is for A3 TDI’s. Size is 55.5 mm. O.D. This is the one that can be swapped onto an AAZ alternator. Brand I bought was INA, $84.50 + tax at V.M.autohaus here in Vancouver. Best price I found was BusDepot for about $62 US.
There is no correlation between pulley size and amperage rating of the alternator, just depends on what was in your car.
On my Passat, it is very easy to remove the alternator (no air conditioning). Make sure to disconnect the battery first! After the alternator is out, an impact wrench with a 23? 24? mm. socket easily spins off the pulley nut. I didn’t have the correct size metric socket, so I used a 15/16”, it did the job. The pulley itself was stuck on tight, but a bit of twisting and gentle persuasion got it off. I didn’t want to tap or hit the pulley as I thought it might damage the bearings or the shaft.
To install the new pulley, I used the Metalnerd Pulley bit set (Part MN3400) $29 + shipping. I will probably have occasion to use this again, as these clutched pulleys seem to have a limited lifespan, and the bit will be absolutely necessary to remove the pulley in the future. I didn’t worry too much about tightening torque (52 ft-lb.?) as it is essentially self-tightening.
The hardest part of the job was getting the belt off and on. Runs great, can’t say as how I notice a difference, but any insurance to save the crank nose on my recently installed new engine is worth it.
Thanks to Vince and others for previous info and the inspiration to do it!
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#1
by
dieselsmoke
on 10 Feb, 2010 07:56
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I just did this update as well. Besides saving the crank nose it also stops the belt flop for the serpentine belt. I had a brand new tensioner and roller in mine and the belt was pretty sloppy, as soon as I put in the clutched pulley there is zero flop now and runs much smoother.
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#2
by
rallydiesel
on 10 Feb, 2010 08:17
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Good info.
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#3
by
veector
on 10 Feb, 2010 08:23
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x2 on good info
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#4
by
GEE-BEE
on 10 Feb, 2010 10:42
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So these are fixed type alt that use the roller /arm tensioner not the plunger/spring alt bracket
Gee-Bee
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#5
by
Vincent Waldon
on 10 Feb, 2010 11:26
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Great stuff... thanks for posting.
Moving to the FAQ section where more folks will benefit from all your great homework in the future.
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#6
by
veedubcanuck
on 09 Mar, 2010 21:16
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In the Mk3 Jetta and Golfs you don't have to even take out the alternator. Just take out the airbox and you have room to get an impact in and do the work with it in the car.
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#7
by
1STGENFARMBOY
on 25 Mar, 2010 17:19
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My 03 jetta tdi had the cluched pully factory and i had to change it
with only 63,000 miles on the car, IT FELL APART, my wife drives it most
of the time and hadn't told me it was makin a noise.
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#8
by
Smokey Eddy
on 31 Mar, 2010 20:04
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So does this include a serp set up on a 1.6?
Could i use this part no. on a 1.6 with a serp set up on it?
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#9
by
neimis
on 31 Mar, 2010 23:26
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Sorry I can't help you, I don't know anything about the 1.6, maybe someone else can chime in. What about measuring the outside diameter of your current pulley? My old one is exactly 55.5 mm
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#10
by
Smokey Eddy
on 01 Apr, 2010 13:26
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That's okay. Thanks for the response. I'm going to try fixing my issue with a new pulley and if things don't improove I'll start looking for a new alternator and THEN if things still don't improove i'll look into a serpentine set up.
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#11
by
GEE-BEE
on 15 Apr, 2010 12:34
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This alt shop show's different #'s
028-903-119 A / Ebay i.d. 200295885792
17 mm bore
38.5 Long
55 mm O.D.
Uses 6 groove Belt
038-903-119A/Ebay i.d. 200350268420
17 mm Bore
50MM O.D.
34.5 Long
Uses 6 Groove Belt
75.00
I purchased this one , smaller o.d., shorter length, great fit on my 90 amp Bosch installed on a AAZ
uses the washer and thread's on , Includes a Dust end cap also....
GB
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#12
by
neimis
on 15 Apr, 2010 22:48
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#13
by
GEE-BEE
on 15 Apr, 2010 23:28
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#14
by
Settings
on 23 Oct, 2010 19:45
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Did the upgrade this afternoon. Used the 028 903 119AA on my OEM alternator. Seems to fit perfectly with no additional modifications. Took a few pictures for illustrative purposes.
Remove the air filter box.
Loosen the serpentine belt tensioner and remove the belt from the alternator.
I had an old impact wrench that fit. I didn't have a 24mm socket so I used a 15/16 12-point. I was able to just hold the pulley with my hand and the impact wrench zipped it right off. If it's really on there, there are two holes on the alternator where you could insert some bolts to hold it in place (1 and 8 O'clock in picture above)
The old and new pulleys...as well as the special bits you need to install the new one.
The triple square blt goes through the splined tool to hold the alternator shaft. Hold the triple square with a breaker bar and tighten the splined tool with a wrench. Don't know what the torque should be. I just put it on nice and snug.
That's it! Put the belt back on. Make sure everything is lined-up. Replace the air filter. Sleep better knowing you may have extended the life of your engine.
Took about 30 minutes. Hardest part was finessing the air filter assembly out
