Thread: Pulley bearing?

New tensioner and idler pulley made no difference, so scrub that.

The noise seems to be coming from the alternator, though cannot be felt if components are touched during running.

A longer video: IMG 2476 - YouTube

I wonder if the alternator rotating components are hitting something inside (gravel?). It sounds a little like a sparking/ shorting noise but as you can see in the video I turned lights off and could see no sparks during running.

So take alternator out???

Originally Posted by Samblers

New tensioner and idler pulley made no difference, so scrub that.

The noise seems to be coming from the alternator, though cannot be felt if components are touched during running.

A longer video: IMG 2476 - YouTube

I wonder if the alternator rotating components are hitting something inside (gravel?). It sounds a little like a sparking/ shorting noise but as you can see in the video I turned lights off and could see no sparks during running.

So take alternator out???

Sounds you are on the right track. You must be an expert at taking that belt on and off now!

I think that'd be my next port of call. Pull the alternator, check it for debris and check for play in the rotor - could be the rotor shaft bearing has **** the bed but would've thought it'd sound different. Or maybe some a rocks gotten in there and damaged the windings...

No way to tell till you get it out but given you've basically isolated it to the alternator it seems the ends in sight.

If anything an opportunity to give it a clean if you've taken it through any mud historically.

Thanks, yeah that’s what I’ll do. Done some water crossings recently.

My Dads money is on a tight bearing in the alternator starting to bind … will report back

Cheers, Sam

Originally Posted by carpdvl

Pull the alternator, check it for debris and check for play in the rotor - could be the rotor shaft bearing has **** the bed but would've thought it'd sound different. Or maybe some a rocks gotten in there and damaged the windings...

I have the alternator on the bench. Nothing inside rattles or sounds loose.

The bearing at the front that holds the pulley on seems very dry though, its squeaks and clicks a little in the reverse direction, though doesn't bind.

Its a Bosch unit. Can these be disassembled for servicing? Can the front pulley bearing be changed out?

Originally Posted by Samblers

I have the alternator on the bench. Nothing inside rattles or sounds loose.

The bearing at the front that holds the pulley on seems very dry though, its squeaks and clicks a little in the reverse direction, though doesn't bind.

Its a Bosch unit. Can these be disassembled for servicing? Can the front pulley bearing be changed out?

Can't say I've disassembled mine but yeah they all should do.

That being said, just had a quick search and this sounds eerily familiar: DEFENDER2.NET - View topic - Puma Alternator Pulley.

Makes sense - its an overrunning alternator pulley which allows the alternator to decouple from the fan belt due to the variations in the belt. Google for more info. The free-wheel mechanism in yours may be stuffed.

There's links in that other thread and part numbers, but looks like need a puller and the bearing. Still should be cheaper than a new alternator.

Originally Posted by carpdvl

That being said, just had a quick search and this sounds eerily familiar: DEFENDER2.NET - View topic - Puma Alternator Pulley.

Amazing. Thanks so much.

They are easy to change, but you need the tool kit to do the job.


Dayco Overrunning Alternator Pulley for Land Rover Defender 130 2.4L 244DT | eBay

13Pcs Alternator Pulley Tool Kit Garage Automotive Freewheel Removal Socket Set | eBay

Thanks, i'm onto it now and think this is my problem.

Really appreciate all the help