LeonLewis

Hi Guys

I have a 928 4.5 1981 Euro

I have started doing some work on my 928.. A few fairly basis things so far.

This time I took on the Alternator replacement. Which looked and should theoretically be straight forward.

I got the old alternator off, hooked the cables onto the new one, got it into place on the chassis (which was not at all easy as it had to be exactly in line with the chassis other wise the long screw wouldn't go in). I then got the long screw in until the last inch where it needs to thread into the chassis. However for the life of me I cannot get the screw to thread in.

I even took the alternator off to check if the screw threads in with the alternator off. But it still does not go in...

From my novice point of view it appears that the receiving end where the screw screws into is buggered. However having read a write up on alternator replacement it appears other people have had this problem, but after persistence did get it in in the end... I however do not seem able to..

Any one have any ideas ?

Thanks

Leon

M. Requin

The boss into which that long bolt goes is threaded all the way through, so if the lead threads and/or face of the boss are truly buggered, you could try (after a thorough cleaning) running a tap in from the back.

Simon928

If I am understanding you correctly and you can't thread the alternator pivot bolt into the block even when the alternator isn't there then your threads are probably messed up and you'd need to re-thread with a Helicoil or a Timesert. If the threads for the pivot bolt are okay, then one thing which helped me was to grind the tip of the bolt to make it a little thinner at the end so that the bolt can find the hole a little easier.

StratfordShark

The bushing at rear tab of alternator needs to be pushed all the way in (it gets pushed out when you undo the pivot bolt when removing alternator). It could be that with the bushing slightly out of flush with alternator tab, it's preventing pivot bolt "finding" the thread on block.

I know you found it awkward lining up alternator (if you can get another pair of hands it helps a lot), but suggest removing alternator, and using a c-clamp - maybe with suitable size socket - to squeeze the bushing flush with tab then try again to install?.

Oh hang on now I see what you said about the bolt not going in regardless, so please ignore above!

LeonLewis

Ok, thanks a lot for the reply's

I will try and thread it again tonight with the alternator off. If it doesnt work I will try and grind the tip of the screw to make it thinner. Failing that I will try and re thread the block..

Will let u know how it goes

FredR

Obviously you need to get the bolt engaging before anything else.

That mounting system [if my S4 motor is anything to go by] is such that it is a tight fit and if like this morning I was refitting my alternator, with the car slightly off the ground on axle stands I have to align the alternator and then use a piece of wood under the alternator with a screw jack to ease it into position as I find it difficult to position it when I am flat on my back. What I do find is that once the holes are aligned and you can enter the bolt into the mount, it cannot do anything else but align with the threaded boss at the rear so Martin's suggestion to profile the nose of the bolt would be of questionable value on my example at least. This makes me wonder whether my example is "atypically tight" or others have "easy engagement".

With respect to the original problem if the bolt came out then logic suggests it should go back in. if the bolt can engage from the rearward side then just chase the threads.

Regards

Fred

LeonLewis

Hi
So what happened was:

When the alternator was mounted and I was trying to get the pivot bolt into the block, I tapped the bolt several times fairly gently with a hammer to see if the bolt was in as far as it would go before trying to screw it in. After several try's it didn't go in, I then took off the alternator and in trying to get the bolt in with the alternator off I realized that how the bracket was positioned meant that the bolt was not at all aligned with the block. And in fact what I should have done was too slightly loosen the bracket before mounting the alternator, and then I probably would have got the pivot bolt in.

Any way with the tapping of the hammer when the alternator was mounted I must of messed up the thread. So in short I had to re thread the block. This wasn't actually as difficult as I thought. And now the alternator is installed! :-)

I installed all the wires, however realized that the ground wire (From the alternator) was previously attached to the alternator itself.. Which cant be right.. So that's my next question. I have a brown ground wire coming from the alternator.. Where should I wire it too? Some where on the chassis?


Thanks

Mrmerlin

please take a picture and post it.

there is not any brown ground wire that goes to the alternator,
its grounded by being attached to the block. might the wire be red and faded?

LeonLewis

Ok this gets interesting... :-) I will take a photo when I get back tonight, pretty sure its brown though

Thanks

LeonLewis

Here is the offending wire which was attached from and to the old alternator... Everything seems to work fine on the new alternator without it...

Alan

Red wires in the engine compartment end up looking brown after many years. What was it connected to on the alternator? and at the other end? There is no need for an alternator ground strap as Stan noted.

For those playing along at home when dismounting an alternator - always disconnect the battery first then all the electrical connections to the alternator before removing it. Reinstallation is the opposite - never connect the wiring before the alternator is mounted - the alternator will almost certainly end up hanging from the wires at some point - bad bad bad..

Alan

The Deputy

Okay, now we need some pictures of the car. Granted, the wire was a nice start.

Although you already know this, now, great care has to be used with just about every bolt on these engines. Most everything is aluminium, so threads get messed up easily. Forcing things just leads to more repairs...and some can be costly.

Glad you got it straightened out and all is well.

Brian.

LeonLewis

This is her at her best, all polished etc..

She is now on jack stands pending several works

The Deputy

Very nice!

It looks like it doesn't have a sunroof....which would be a plus if you're tall or you like rain-free drive-thru car washes.

Great looking car, good luck with her.

Brian.