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Alternator, removal / slipping clutch pulley

H

Hughb

Trainee
Joined
15 Jul 2019
Messages
80
After 500+ taps (as hard as I could hit the bolt in the space available) with a 7lb hammer, I failed to budge the rear bush in the alternator top bracket to facilitate its removal. In the end I managed to lever the double ended bracket upwards after inserting a wooden block underneath, to free it from the upper engine mounting point and then perform the required clockwise rotation to remove it. Levering up the lower LH mounting bracket and screwing in the long bolt when the bracket was clear of the mounting hole really helped ( with trying to keep it horizontal). This may not make a lot of sense unless you have struggled with a seized rear bush when attempting alternator removal.

The reason for removing the alternator was to renew the regulator, by way of preventative maintenance on an 86000 mile car. What else do you do after watching England disappoint on the rugby pitch?!

Now that I have the alternator in my mits I notice that the pulley, although a plastic capped one, does not appear to be a slipping clutch type, which I thought it was supposed to be. Can someone clarify what type of pulley I should have? Is a fixed one an issue? Can a slipping pulley seize? Is it easy to swop out the pulley ( I have a slipping one available)?
 
The solid pulley has a visible nut in the center. The freewheel type has a plastic cover and a multi-spline under neath that plastic cover. Most likely yours is seized if it doesn't slip in one direction and hold in the other. You'll need the appropriate tool and impact wrench to remove it.

I believe manual cars will have the freewheel type and tiptronics the solid pulley.
 
Thanks for that.

It has the plastic cap and splines, so it's the freewheel type .... it must be seized. So a little bit more maintenance on the alternator than I was anticipating!

I can get access to the special tool to remove, but am not expecting a 'walk in the park' (having seen others attempt pulley removal)

Obviously I did not need to remove the alternator to identify this issue ... a good thing to check whenever the aux belt is off.
 
I know what you mean re bush and removal. I think gently levering the alternator out is the better option. Prior to refitting you'll need to put the bush back. I'd suggest trying to draw it into its housing using a length of threaded bar and some appropriately sized sockets. Hitting it with a hammer risks fracturing the housing.
 
Removing an alternator .. we lever it out .. it's a pain but that's how we do it ..

Using the bolt as a punch to try and knock back the metal slider is asking for trouble .. it will snap the alternator bracket ... seen it done .

At this point the surcharge you pay which you get back on exchanging the old alternator wont be paid back .. its junk , they don't want it and the job just got a lot more expensive .

To refit an old alternator .. in other words to move this sliding pivot backwards .. get a large socket that will enable the slide bush to fit inside of it but small enough that it locates on the bracket to support it.

2 people are best .. one person holds the alternator on the socket and on the floor .. this supports the bracket .. you can then using the bolt hit it to move it back a mm or 2 .. no more is needed.

Fitting is then a hell of a lot easier .

Freewheel or not and i see no reason why you can't use either .
 
Wish I had posted before I got out the 7lb hammer, could have saved myself some time, although the activity was possibly quite cathartic after the rugby!

I am inclined to use a hydraulic press and push out the steel boss, emery it in a lathe and refit ...... I am a little concerned that if it is still completely solid in the bracket after pushing it back, there is a chance that I could over stress/break the bracket when tightening up the long bolt.

Thanks deMort for the 'stay calm' advice on the freewheeling/fixed aspect.
 
A press will work just fine .. i post as to how i do things though .. socket on the floor works just fine .. and i've done a few :)

1-2 mm is all that's needed and im kinda dubious about pushing it too far .. if tight then you have the same problem doing it up .. the stress is on the bracket .
 
Whoops, deMort, its my general (but not specifically auto) engineering experience over promoting itself! A 0.5mm knock back on a socket it is!

Having freed up the alternator I can see rather too much oil on the top of the engine block below/behind where the alternator sits. (The alternator main cable is out of focus on the RHS of the pic).
the blue + white cable looks a bit soaked for my liking.

Can anyone suggest what the source of this oil might be? ...and what is the blue+white connector connecting to? I have had no time to go hunting further and I am coming to understand that it is better at ask first!
 

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0.5 mm will do .. it's a tiny amount that will allow you to easily refit the alternator .

The wires connect to the knock sensor that side .. ignition related and to do with the ign timing ... i can explain it in depth if you really want a boring read lol .

Oil there is not uncommon .. you do get a reasonable amount of oil in the inlet tract , it will over time leak out of the rubber parts on the inlet manifold and drip down ..

Your image is a long term build up of this .. not something i would worry about .

EDIT .. just to add that wiring plug has an internal seal .. the oil will not penetrate it .
 
I had to replace my oil filler tube and that's exactly what the top of my engine looked like as well. I guess oil was just leaking from the filler rather than going into the engine.
 
Thanks again, deMort, that's good news. I will give it a bit of a clean up there, before I put back the alternator, with a new freewheel.
.... discovered that the alternator was in fact a 997 part numbered 150amp Bosch one so my 'preventative maintenance' bright idea of renewing the regulator looks like overkill, as it is obvious that the complete alternator has been replaced already (although not shown in the last 5 years of bills which I have).
(I'll do a bit of research on knock sensors ... just because I have 'bumped' into one!)
 
Image ....

Ignition timing is retarded when a knock is detected .. knock being an incorrect combustion .. detonation etc .. due to timing to far advanced .
 

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