Alternator/Generator Stand

Just about the first thing we replaced in this car was the alternator stand. It was cracked all the way around near the bottom, and oil would run out all over the place whenever we put oil in the car. Could this be a result of stress and strain caused by the fact that this engine ( a '71) is equipped with an alternator rather than the generator that it's supposed to have?

Dave replaced the alternator stand with a cheap one purchased from one of the VW parts catalogs. This stand, like the first one, was made of pressed powdered metal -- made in China.

… I took the fan belt off… and started jiggling things and found that the whole assembly was loose -- because the alternator stand is broken in two right at the base, just like before! As you recall -- the alternator stand was the first thing we replaced on this car because it was cracked all the way around near the base.

What concerns me most is the underlying cause. There's got to be something basically wrong that is putting so much stress on the alternator stand.

That IS strange. Here's a thought -- there are several different fan backing plate shapes (the piece which bolts the fan to the shroud). I don't know all the details, but even though they look similar, the non-doghouse one is different to the doghouse one (because the fan is 5mm wider) and the 38amp generator (buses/kombis) plate is different again (that generator is longer). I wonder if the Beetle generator and Beetle alternator versions are a little different, and whoever overhauled your engine used the wrong one -- putting stress on the pedestal. I can't see any other place of conflict which would stress the pedestal.

Now THAT would certainly cause some stress on the alternator stand. It has the spinning weight of the fan on one end, and the downward force of the tightened fan belt on the other. No wonder it cracked.

I can't see you leaving four bolts out altogether, but then if they were there, where are they now??? They have nowhere to go except inside the engine compartment. Didn't have 4 spare bolts last time you dropped the engine did you?

I haven't had time to have a thorough look -- they may be there inside the engine compartment. You know, both bolts that hold the oil cooler tin in place also vibrated loose, and this afternoon I also discovered the cause of the recent intermittent miss -- the nut on the positive side of the coil had vibrated loose, and the wire was just loosely connected.

I have a very perplexing problem with my '73 SB ... For the second time in our experience with this car (2-1/2 years), the alternator stand has broken in two -- a circumferential crack all around the base of the stand. This was the first of many problems that we have repaired in this car since we purchased it in June 1997; now it has happened again.

By way of background -- this car (chassis no. 133-3001-550) was built late in the 1973 model year. The engine in the car was replaced by a PO with a 1971 model (#AE320891) that is equipped with an alternator with an exterior voltage regulator (under the rear seat). VW changed from a generator to an alternator in mid-1973, so originally this engine had a generator rather than an alternator. I don't know whether this change has somehow altered the system so as to put excessive stress on the alternator stand, but it's a consideration.

Not only is the alternator stand broken in two, but ALL FOUR of the fan cover bolts have worked themselves loose and are missing! The bolts associated with the oil cooler tin have also worked themselves loose. I don't know whether this is cause or effect.

I am in the process of raising the fan shroud and pulling the alternator/fan assembly out of the car. I have a new alternator with an internal voltage regulator on order from Aircooled.Net, but I am very anxious for your advice before putting the system back together to make sure that I have addressed the root cause of this problem so that it doesn't recur. John has recommended that I replace the fan, but I'd very much like to hear what you have to say about this situation before I proceed.

I have *never* heard of a failure like this...never.

Given all the other mysterious things happening (loose bolts), I very much agree that the fan should be replaced. There are two fans, one for non dog-house and one for dog-house coolers. Are you also aware that the alternator belt is different from the generator belt?

It's a weird problem, and I just can't think of why there would be stress associated with the fan to alternator, and alternator to stand fixings which would a) loosen the fan mount bolts and b) crack the stand. Where the bolts went is a big puzzle too -- maybe they are lodged behind the induction manifold just below the fan plate, or maybe they are in the well under the engine pulley.

As I said previously, the only thing which comes to mind is perhaps an incorrect fan mounting plate used on the alternator.

I AM going to have to raise the fan housing, even though the alternator is totally loose, so that it will clear the intake manifold. Hopefully that will become obvious when I get the alternator/fan assembly removed.

I was wondering if you would. That would be a "given" on the single-port engine (one-piece manifold) but I wasn't sure with the dual port. But I guess the outer ends would be in the way (on the right side particularly).

I went out tonight and took the alternator strap off, screwed in the two top bolts in the fan cover to hold the alternator up (my concerns about the nuts being stripped were unfounded) and removed the broken alternator stand. It's now sitting on my workbench in two pieces.

I'm not understanding this. One would think that the fan cover bolts were inadvertently left off, causing vibration and stress ...

I'm pretty sure the problem lies with me. I dug out a picture that I took of the engine after I had it all reassembled and cleaned up, sitting on the patio before reinstalling it. I scanned the picture at 200% and took a close look at the two top bolts in the fan cover. The blow-up is a bit fuzzy, but I'm pretty sure the bolts were missing! Apparently *I* neglected to put them in.

Like Pogo said, "We has found the enemy, and they is us!" I feel like an idiot!

I don't think leaving all four bolts out would make any difference. The cover is only there to keep the air inside and to locate the shroud reference to the fan.

I don't think you're going to be able to take the blame for this

But -- if leaving the bolts out isn't the reason the pedestal broke, what IS? This is the second time this has happened in this car -- there's got to be some underlying problem...

I keep coming back to the alternator itself. This engine is 1971; VW didn't put alternators in Bugs until mid-1973, yet this Bug (itself a 1973 model) has an alternator with an external voltage regulator. Is it possible that this mismatch is somehow causing a problem that is putting excessive strain on the alternator pedestal?

I would be looking for more clues, I guess.

Does the fan belt exhibit any peculiar vibrations thru a range of RPM's? (I assume it's not overly tight.)

I'd try to rig up some way to spin the Alt at high RPM (without the engine running) to look for unusual vibration.

After I got the fan out, I'd examine it closely for any signs of damage. (BTW, you should have an impact wrench to get the fan off.)

I got this reply from my mechanic friend. Couple of good points in it -

1. Cracked stands are not uncommon.
2. Cheap stands crack far more readily than the genuine article.
3. The 50amp alternator and 30amp generator fan mounts are the same, so that should not be a problem for you (there are several different ones -- he mentions the 38amp genny (used in buses).

Of course the alternator pedestal MUST be replaced. I'm told that there are two qualities available -- the el-cheapo made out of pot metal, which breaks easily, or the high-quality original VW part. Given our history (two broken pedestals in as many years), I want to get the good one. The question is, WHERE? All that I've seen are the el-cheapo ones.

If you need a genuine VW stand, I do NOT have them.(Aircooled.Net) You will have to get it used somewhere.

You were recommended to me as a good source for N.O.S. VW parts.

I am in the process of replacing the alternator on my '71 SB. I need to also replace the alternator pedestal, which is broken. I'm trying to find the higher-quality original to replace the el-cheapo made-in-Taiwan part, which has broken twice for me now.

Can you help? I don't find the part in your on-line catalog.

This part does not appear in our catalog due to the poor quality units currently available. Unfortunately, I do not have a source for an original unit, sorry. Try locating a used piece, that's your best bet. Russ' Recycling in Duarte, CA is an all-VW wrecking yard, they may have one.

Thanks for the great lead to Russ' Recycling! I just got off the phone with them, and they are sending me an original-equipment alternator stand for only $15!

We have a dearth of wrecking yards around here that have VW stuff, so this is a very valuable find!

Tomorrow a new (used) original alternator pedestal will be arriving (hopefully) from a wrecking yard I learned of in Southern California (Russ' Recycling). Once I have it installed, then the reassembly will begin -- a new alternator and a new CDI unit, with all associated parts (fan, etc.) cleaned and painted -- its gonna be gorgeous!