Alternator Belt Adjustment - Nut Required?

[mikel]

I had the squealing noise at start up occasionally and read the thread on fixing it.

Unfortunately I can't see any of the photos attached in the thread, but there appears to be a missing nut on the adjustor bracket on my car. Where the long adjustor bolt threads into the block, poking out the front is a bolt that looks like it needs a nut (see attached photo). Nissan couldn't tell me whether a nut is meant to go there or not

[BHDave]

There definately isn't a nut needed. I think your bolt is through the wrong way to be honest, the block is threaded from memory and the bolt when tightened should lock the assembly in place against the bracket. As it is now it can potentially flap about.

[wrxhoon]

The pic is not very clear so i cant tell if you have the bolt that holds the block on . As BHdave said the block is threded and is bolted on the alternator with another bolt M8 from memory, you undo this a little then turn the long ajusting bolt until you have the correct tension and tighten the other bolt .

[GeeTR]

Agreed

[RANDY]

Agreed agreed.

The long bolt does not need a nut. It is locked into place by another bolt that runs perpendicular to the one pictured. Undo that locking bolt first, then the long one in the picture will turn without much resistance.

[RANDY]

Oh I see what people are saying about the bolt being backwards. I think they're referring to the locking bolt. You can see the end of it poking out the front. I guess now this is the one you were talking about? It's threaded in that block where the head of the bolt is. (towards the rear)

I can't remember which way round it is supposed to be, but if it's backwards, then it won't be doing any locking whatsoever. I'll check mine next time I go downstairs for a smoko.

[SteveL]

On every RB I've ever worked on that block is not threaded other than for the long adjustor bolt, but is clearance drilled and it's actually the mating lug on the alternator that is threaded (ie the part where you can see the bolt sticking out toward the bottom of that photo). So the lock bolt (which is what it's for - securing the adjuster mechanism) passes through that block, then the long adjuster bracket - which has a long, slotted hole - and finally screws into the threaded lug on the alternator. The idea is that the bolt clamps the block and the alternator to the adjustment bracket, which itself is attached to the block at the waterpump.

Looking at that photo I suspect your problem could be that the bolt is too long. The standard bolt would only stick out from the alternator lug by a few mm at most. It's not standard and it's possible that there isn't enough thread, which means the bolt isn't able to be tightened sufficiently before running out of thread. This would mean that it would _appear_ that the bolt was tight when it actually wasn't and that might explain your squeels. Either that or some idiot has stripped the thread in the alternator lug and slipped in a longer bolt to fix the problem, in which case there should also be a nut on that bolt (and the fact that there isn't one would also explain the squeels, etc).

[RANDY]

There you go! The bolt is in the correct way. And as SteveL said, I can also see that my locking bolt doesn't stick out anywhere near that far.

Edited January 12, 2007 by RANDY