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Mon May 26, 2003 5:46 pm

mine keeps breaking and i can't figure out why. i've been thru six of them now. the motor is a 1600dp. it was fine for the first 5000 miles, now its breaking them regularly. i thought maybe the screws were loose that hold it to the fan shroud. i thought maybe i overtightened the strap. it seems to break when i'm decelerating coming off the highway. roadside repairs suck, even easy one's like this.

any insight is appreciated

Mon May 26, 2003 6:15 pm

Loose fan housing? Bad generator bearings? Any excess noise before it snaps? Are you using cheap Brasilian replacement straps? Something is stressing it. I had this problem years ago on a '59 and as I recall, snugging up the two screws that hold the fan shroud to the cooling tin did it.

Mon May 26, 2003 6:52 pm

I'm guessing it is a misalignment between your pedestal and the fan housing, causing the force of vibration to be borne by the strap instead of the pedestal, which is supposed to be the main support. What strap(s) did you use after that West Marine one gave out? Did you get some more at Bugout for the ride home?

Mon May 26, 2003 7:40 pm

sounds like you are going through as many alt. straps as i am going through fuel filters!!! that sucks. good luck Gibbs!

Mon May 26, 2003 8:13 pm

I had one of the aftermarket ones break a few years ago,it turned out that I hadn't put the part where the bolt goes through down far enough,and the strap end was slightly bent after tightening it,which pulled the spot welds apart.

Mon May 26, 2003 8:34 pm

How much play do you have in your fan belt?

Tue May 27, 2003 4:17 am

fan belt tension is right.

Tue May 27, 2003 6:04 am

i've been having the same problem recently until i had my engine out for repairs and found an air cleaner clip had come off and clipped itself onto my fan blades, throwing the fan out balance.

Tue May 27, 2003 9:07 am

Have you checked for a bur on the stand itself? Just an idea.

Wed Dec 28, 2011 4:13 pm

I know this is an old thread, but the same thing just happened to me. Could it be there is a difference in Alternator straps and Generator straps?

Maybe the one I put on (WW) was too short, and I over tightened? It was brand-new and broke on a single drive and the one I replaced was broken.

Not sure what the solution to this thread was.

Wed Dec 28, 2011 4:59 pm

I have never seen one of these break http://www2.cip1.com/ProductDetails.asp?ProductCode=C26-903-402

I have seen many other types of clamps break, these are the only ones I will run

Wed Dec 28, 2011 5:03 pm

AWESOME. I just got finished hitting the purchase button on jbugs for the same part.

I'm all freaked out thinking the fan is messed up or something else in there is wrong. The zink one broke in the middle no where near a weld.

I think I'm going to have to schedule a engine removal day. I'm thinking to get the thermostat flaps installed and check the fan and dog house cooler and all the bits attached to the alternator to make sure everything is lined up and clear. Get the right tin etc etc.

Its like 'If you give a mouse a cookie' hahah

Thanks for the link! Hope it gets here before the weekend, I'm dying to drive it w/ the new SVDA and Carb all tuned up.

Wed Dec 28, 2011 5:42 pm

sub-hatchtim wrote: I have never seen one of these break http://www2.cip1.com/ProductDetails.asp?ProductCode=C26-903-402

I have seen many other types of clamps break, these are the only ones I will run

I broke 2 of those in one weekend. Turned out the the bearings in the alt were cooked. I ended replacing the alt, fan, strap, and belt.

Wed Dec 28, 2011 5:43 pm

that is normally where I have seen those other straps break. It is due to them being flexed multiple times fatiguing the metal

Wed Dec 28, 2011 6:23 pm

Thinking back I did flex it a couple of times to see how it fit best.
I will still post a todo date for fan and alternator inspection day. I don't think the fan is as quiet as it could be. That's what got me to poking around in the first place.
What's the right procedure step wise for the alternator strap? I'm guessing it should be snugged first then the tin screws last?
Seems putting the strap on last may not be best?

Thu Dec 29, 2011 12:43 am

tin screws first then strap then the 2 screws that attach the shrowd to the cylinder tins

I think I haven't touched a air cooled motor in a couple years due to being in germany

Thu Dec 29, 2011 5:26 am

bcampagnolo wrote: Thinking back I did flex it a couple of times to see how it fit best.
I will still post a todo date for fan and alternator inspection day. I don't think the fan is as quiet as it could be. That's what got me to poking around in the first place.
What's the right procedure step wise for the alternator strap? I'm guessing it should be snugged first then the tin screws last?
Seems putting the strap on last may not be best?

My fan was making a heck of a lot of noise when it was breaking those straps. It started out not so bad, and then gradually got louder. Basically when the alternator bearings are bad the fan just bounces in the shroud. Take the belt off the alt and see if there is any play in the alt shaft, up and down, side to side. Oh yeah I also replaced the fan backing plate, mine was all bent and warped.

I really think my situation was due to the belt being to tight for a long time. It was only the front bearing that wore out. That bearing can be replaced. When I got home from that trip I took the alt apart and replaced that bearing as well as the regulator, now I have a spare.

Thu Dec 29, 2011 7:00 am

Another thing to check is pulley alignment between the alternator and crank pulleys. In a beetle you can eyeball this with the engine installed. In a bus, not so much.

Hey, Uzi , what solved your problem?

Mon Mar 12, 2012 9:06 pm

Looking for some tips. :?

I just busted my 5th strap. I am getting those nice ones.
Here's where I'm at:
New alternator (85 Amp) - I'm ready to have the stock Bosch rebuilt (bearings). I read that maybe these rebuilds are not the exact right size. . .
I have aligned the main pulley with the new alternator pulley.
New fan belt.
Installed by loosening all the tin screws I could, installed new alternator and made sure it spun nice and quiet. I then re-tightened all the tin screws and tightened the alternator strap, then tightened the fan belt.

I'm at a total loss. How can I tell if the fan is good or balanced?
When everything is back and ready to run, when I test the fan tension, if I grab the fan belt with one hand (open grip, thumb and fingers), and squeeze the belt just under the alternator, I can still get the alternator to move a small amount as the fan tension increases. . .
It's almost as if the stand does not have enough surface area with the strap to really snug things down.

I have an old german stand that looks like an alternator stand, but the curve is too 'steep' - that is, the alternator does not sit flush in the curve. This is the spare I have, NOT the one on the Bus.
I mention that to ask - when / if I look for a German stand, besides the clearance for the Alternator, is there a difference in stands (alt. / gen) in the curve area like this?

Next steps? Replace fan with a welded balanced one? Put Bosch alternator back on? Replace alternator stand?

I did have to grind a fair amount off the alternator to have it clear the alternator stand.

Without this grind-age, the pulley was waaay too far aft of the main pulley.
As I tightened the strap, it walked the alternator aft.

I can get more photos of how things look as installed to get more detail on this grinding that was required. The stand does NOT have a VW logo NOR the german text for 'firing order'.

How much (if any) movement should there be once everything is tightened?
I tried more torque on the strap, less torque, 1" fan belt tension, .6" (Bentley) fan belt tension.

It ran super quiet and sounded like a sewing machine for one day after all the new bits were put in.

The fact that the old alternator front bearings are shot (the bearings nearest the fan) - could that indicate an out of balance fan?

Sorry to be so long winded. I'm just bummed I can't figure this out.

Tue Mar 13, 2012 2:10 am

Alternator stands have a narrower curve than generator stands.. 6volt stands have a smaller curve....6volt generators are smaller