Have you checked to make sure all the pulley's are true and not out of round?

I know that VW made a change to the alternator pulley as I ordered a replacement and got a nice billet one to replace the two-piece metal one.

I'd also check to make sure all the pulleys are aligned as well.
How tight are you adjusting the belts?

Todd
'88 Westy

 -------------- Original message ----------------------
From: Larry Chase <roadguy@ROADHAUS.COM>
> Volks,
>
> TC ... In my case it's the alternator bracket that is breaking not the
> alternator adjusting arm.
>
> See Photo
>
> http://www.roadhaus.com/images/alt_bracket/alt18.JPG
>
> BTW .. A few other details.
>
> - 8 broken brackets in 3 years (~50k miles)
> - 1 broken alternator bracket stud
> - 2 alternators
> - 2 water pumps
> - One engine / AVP rebuild installed just before the first broken bracket
> problem
> - alternator belts 6-8
>
> I have always felt there must be some weird vibration causing the problem.
>
> I've probably tried all the more common solutions ...
>
> - Belt not too tight
> - Belt not too loose
> - Changed alternator
> - Tried one of Frank C's alternator brackets with extra welds to strengthen
> - Tighten lower alt bolt .. Was slightly loose to allow belt adjustment
>
>
> Dennis and BennyBoy brought up some things I hadn't considered before.
>
> - slightly offset/oscillating crankshaft pulley
> - check the mounting surface on the case .. Is it flat
> - use grade 12.9 hex bolts, hardened washers, loctite & a torque wrench at
> 32 ft/lbs.
>
> Thinking back it's possible that one or more of the lower alternator bracket
> bolts was slightly loose at the time of breakage.
>
>
> good road,
> good adventure,
> good life,
>
> larry chase
> www.roadhaus.com
> soon to be roadhaus.org
>
> - - -
>
>
> Date:    Sun, 15 Oct 2006 10:28:45 -0700
> From:    TC <trclark@SHAW.CA>
> Subject: Re: 85GL 1.9 Busted alternator mounting bracket stud ..2nd time in
> 2
>          years
>
> Larry
> It looks to me like you are braking the alternator adjusting bracket ? for
> me it is the stud/bolt that go into the block hairs from the water jackets
> :( on the lower bracket under that alt : realy not feeling good about right
> angle drilling that stud out again ...
>
> >Alternator Brace Photo
> >http://www.roadhaus.com/images/alt_bracket/alt03.JPG
>
> And the brace pic is bracing the adjusting bracket ...
>
> so I guess it looks like i am gonna see if a local machine shop can come up
> with some type of a brace maybe both top & bottom
>
> - - -
>
> Date:    Sun, 15 Oct 2006 12:13:42 -0700
> From:    Jake de Villiers <crescentbeachguitar@GMAIL.COM>
> Subject: Re: 85GL 1.9 Busted alternator mounting bracket stud ..2nd time in
> 2
>          years
>
> Those are a little wacky guys.
>
> I was wondering Larry if you had tried welding a short piece of 3/4" or 1"
> steel strap at 90 degrees to the top side of the adjustment arm to stiffen
> it. Of course it might then transfer the load to the other bracket and cause
> a failure like TC's!
>
> Just thinking.....
>
> - - -
>
> Date:    Sun, 15 Oct 2006 17:22:52 -0400
> From:    Dennis Haynes <dhaynes@OPTONLINE.NET>
> Subject: Alternator brackets! Why they break.
>
> The Water Boxer Alternator Bracket is one of those parts that can cause a
> lot of grief. The problem with replacement is that the cause is often not
> determined and corrected. To make matters worse, failure usually breaks the
> studs and the moving bracket destroys the mating surface on the case so a
> proper fix is difficult.
>
> Failure can be the result of mechanical fatigue or corrosion of either the
> bracket or the mounting studs. Improper belt tension, (too loose) or a bad
> rear bearing can create shock waves or vibrations that put the mounting to
> the test. After rear bearing fails, the rotor can hit the stator windings
> taking chunks out of both. Rebuilds often use these damaged components.
>
> Many folks leave the bottom alternator bolt just loose enough to allow belt
> adjustment. This is a no-no. Any vibration will cause some movement at this
> joint and now you get a little velocity. The alternator now becomes a high
> speed hammer. Keep in mind that little alternator is spinning at some 2.5
> times the engine speed. Yes, that 4,500 rpm hill climb is spinning that
> thing at almost 10,000 rpm and that belt you left loose trying save the
> bearings is flapping all over putting all types of cyclic harmonic loads on
> the mountings.
>
> So the bracket finally gives out and we have the broken studs. We some
> drill, prey, curse whatever and get them out. We restore the threads and get
> new studs, nuts, and a bracket. Is the mounting surface on the case flat? It
> needs to be. Get a big file before installing the studs. Where did you get
> the studs? Most studs are property class 5, (grade 5.8)or lower. These are
> OK for crushing that exhaust gasket, maybe. Not to be used here. You need to
> Property Class 10, (grade 10.9) or better. The nuts and washers have to
> match. These can be hard to come by. A set screw can be used as a stud. I
> myself like to use grade 12.9 hex bolts, hardened washers, loctite and a
> torque wrench. Think CV joints at 32 ft/lbs.
>
> That bottom alternator bolt also needs to be tight. Both sides of the
> alternator should be true and the hole should not be worn into an oval. If
> you can adjust the belt, the bolt is too loose.
>
> Looking at Larry's picture, I see thread impact marks and corrosion in the
> mounting bolt holes. It came loose before it failed. I also see some wear
> marks where the alternator sits. It was probably moving there also. There
> may be a problem with the alternator but it looks like the fasteners failed
> first (lost preload and loosened) and the hammering caused the final
> failure. Additional supports or braces probably will not help this. Get rid
> of excess vibrations and improve the fasteners and all will be good.
>
> Dennis
>
> - - -
>
> ate:    Sun, 15 Oct 2006 21:40:55 -0400
> From:    +++++++++++ <vw4x4@VERIZON.NET>
> Subject: Re: 85GL 1.9 Busted alternator mounting bracket stud ..2nd  time in
> 2
>          years
>
> REplace the Alternator....  Its way out of balance.
>
> - - -
>
> rom: Benny boy [mailto:huotb@VIDEOTRON.CA]
> Sent: Monday, October 16, 2006 6:56 AM
> To: VANAGON@GERRY.VANAGON.COM; Larry Chase
> Subject: Re: 85GL 1.9 Busted alternator mounting bracket stud ..2nd time in
> 2 years
>
>
> Ho men!!! can you believe that you went from that engine condition:
> http://www.benplace.com/roadhaus/100_0213.jpg
>
> To totday's condition... dirty dirty dirty boy...
>
> he he he
>
> To all: Remember one thing, ALT oscillation is normal to a point, i found a
> few reasons for those ALT bracket break! -old alternators (unbalance) -Wrong
> lower ALT bolt holding the ALT (miss-align) -ALT fan unbalance (you may have
> a rebuilt ALT but they use the same fan) -weak bracket(S) (normal wear)
> -poor design -Old water pump -too tight or too loose V-Belt -slighly
> offset/oscillating crankshaft pulley (pulley has been hit with a hammer and
> the pulley groove is not perfect anymore) -Bad V-belt
>
> Current draw! mmm.... i guess it's possible
>
> Another thing, worse than the ALT bracket breaking.. that oscillation can
> wear out the water pump quite fast!!! lately, i brand new pump went wrong
> (leaking) after 1500miles, i tought it was a defective one... nop! that ALT
> was the reason.
>
> Larry idea is nice...
>
> Ben
> http://www.benplace.com/