What is this touching Alternator Belt

[flashman1207]

Just put new Alternator on and when putting new belt on noticed that the belt was touching this cylindrical thing attached to engine (see pic). It looks like the old belt just ran across it as it has a wear point where the old belt was. However, when I removed it it appears to be some sort of jockey wheel with bearings inside. It spins freely when removed but when attached and tightened it no longer spins around. Anyone know what it is and is it supposed to spin when the belt is touching it. Shall I just remove it?

Thx
Tony

[BigRAWesty]

Its to stop the belt slapping the ac pump. And yes it should spin. There should have been a small tube like spacer behind it which presses against the block and inner race, allowing the outer race to spin..
A washer or 2 might also have the same affect asking as there clear of the outer race.

Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[flashman1207]

I've put the damn thing back on now but I'm sure there was a spacer behind it. SO why would it not spin? There is an 'end plate' at each end which the spacer would be pushing against at one end and the nut pushing against at the other. This 'squeezing' of the ends must be what stops it spinning. But how to fix it? Can you all check yours and see if it spins?

[BigRAWesty]

Spot on. The side loading would be seizing it up. How tight is it before it seizes? Might be simple over tightening it. A dollop of thread locker and a little nip up might be all it needs

Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[Shaunous]

I havnt noticed one on my nissan, but my old faithfull hilux had one, that everytime I pulled up and turned the engine off it would be still spinning and making a whining sound, and I got sick of everyone asking 'what the hell is that noise, is your engine blowing up'. I have checked since and the belt is not slapping on anything, so in this case it was ok to remove. Yours may be also, but check the belts afterwards.

[MudRunnerTD]

My understanding is that it is an Idler pully and designed to be the tension adjustment for your belt? on a TD42 it is anyway?

[Bloodyaussie]

I need to adjust my power steering and a/c belts and noticed the adjusting thread was stuffed and could not be adjusted so now I have to part off my donor car and will try and do it this weekend..... now I never noticed that little roller thingy on my and will now take a closer look, thanks for advice Westy!!!

[BigRAWesty]

My understanding is that it is an Idler pully and designed to be the tension adjustment for your belt? on a TD42 it is anyway?

Dunno if it can be moved? Pretty sure its just a bolt into the block. Belt tension is done via the alternator.

Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[threedogs]

I wouldn't be removing it, get it freed up. Its there for a reason

[flashman1207]

Kallen,
I think I will put some thread lock on and back off the tightening. What did you mean by 'a little nip up'?

[BigRAWesty]

Kallen,
I think I will put some thread lock on and back off the tightening. What did you mean by 'a little nip up'?

As tight as it will go before locking up..

Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[flashman1207]

Thanks, all sorted.... hope the nut doesn;t fall off as I couldn't tighten it much at all.... threadlocked though