Hi Ken,
Thanks for the response. I am a bit confused because the bolt that I have doesn't go through any other tensioner, pulley, or any other item. It bolts just the alternator to the engine/oil housing. The number you gave for the lower bolt seems to be for a pulley or different section of this area.
When taking the old alternator off, I noticed that the lower bolt was a bit longer than the top bolt (around 170mm) so kept them in different areas of my workspace so I wouldn't get them confused. But I did notice that they were both the same diameter - M10. But I may be mistaken in this. I just remember it was longer than the top bolt. I also noticed that it protruded out the back of the rear ear and nut quite a bit, so it could be that the alternator was changed prior to me doing it and someone put the wrong sized bolt back in.
The new alternator has a nut welded to the back of the lower rear 'ear' of the alternator and when putting the lower bolt back in it became extremely tight with more than 1/4" proud of the surface of the front alternator ear, before I stopped tightening for fear of stripping the bolt/nut thread. That means I have most likely cross-threaded the bolt which is why I am looking for a new one. The other reason I am having to replace the bolt is because there is some squealing coming from the belt, which tells me that there is a slight misalignment with the alternator pulley due to the bottom bolt not being tightened enough to prevent the alternator from moving around slightly, however slight it is.
The best thing would be for me to remove the alternator and actually measure the distance from the front ear to the back ear (outer surfaces) to confirm the approximate length. Not looking forward to that as it's quite cold here now. But when I do I will let you know the result.
Saturday, November 15th, 2025 AT 10:27 AM
