td5 shredding serpentine belts.

[Wicks89]

Guys,

About 2 weeks ago fitted a new belt to my td5, along with new fan pulley bearing and new stationary idler pulleys.
Drove to Wodonga from Sydney and the belt had become mis-aligned and stripped about 3 ribs from the belt. (Effectively making it narrower).

Somewhat alarmed I refitted the old belt which I had kept as spare. The belt kept misaligning over the stationary idler pulley closest to the fan pulley. I corrected the alignment with 1 small washer between the mount and the little allow spacer. Checked - all good.

Drove back to Sydney, belt was fine, drove to work today and the belt came off totally (though undamaged). I refitted it and drove not 6 kms, before the belt stripped itself into shreds.

The car is sitting on Holsworthy Barracks now, Theres some soot near the alternator. I have a feeling the alternator is to blame.

Has this ever happened before?

[Loubrey]

Wicks89,

Not Td5 experienced, but it does sound as if you've got one of the pulleys about to throw a bearing...

In my experience with 300Tdi's, they will also do that if one of the pulleys is struggling to turn, effectively braking the system. Might well be the alternator is the rubber "soot" is on it which would indicate belt burning as it slips on the resisting pulley.

The other instance of belt trowing might be a fraction of "wobbling" on a deteriorated bearing.

Might be worth eyeballing the belt with a bit of revs to check how it runs, but checking each pulley for rotation and possible "grind" would be my first suggestion.

Cheers,

Lou

[Tombie]

Have you fitted a new Tensioner unit?

[Wicks89]

Sorry for the rushed post and foul language - warning: received.

Tombie: I fitted a new tensioner unit about 10,000 km ago, and had it off completely about 5000 km ago when the alternator/tensioner bracket broke and I had to replace it. Spun fine, no grinding or wobbles.

Loubrey: all the free-spinning pulleys (Fan pulley, tensioner pulley and 2 stationary idler pulleys) spin fine, no grinding or wobbles that I can see. I just replaced the stationary pulleys and the fan pulley bearing. The water pump seems fine too, the only one I can't tell with is the Alternator because theres resistance when turned.
Is that normal? I suspect the alt because the cam plug leaked for a few hundred ks and oil got all over it. The soot near it looks like exhaust soot, really fine and black, so must be the belt burning up right?
Could the gunk have ruined the alt bearing?

[p38arover]

Tom, last weekend I was chatting with a Land Cruiser owner about his shredding belts. His mechanic said he'd heard of (but not experienced it himself) alternators being the cause, possibly from seizing bearings.

The upshot was that the alternator was replaced and the owner had no more problems.

[Loubrey]

the only one I can't tell with is the Alternator because theres resistance when turned.
Is that normal? I suspect the alt because the cam plug leaked for a few hundred ks and oil got all over it. The soot near it looks like exhaust soot, really fine and black, so must be the belt burning up right?
Could the gunk have ruined the alt bearing?

Like Ron said, bearings just have a finite life span (dust, muddy water etc) and your alternator just seem to have reached its end. The rubber of the belt being friction burned will look like exhaust soot as well (smell like burned rubber though), but that's unlikely to have contributed to an alternator bearing failure.

Sounds like its still salvageable though... have it out and have an autospark do a refurb (unless you have those sort of skills).

Cheers,

Lou

[Disco Muppet]

Td5 alternator refurb kits are readily available

Sent from my HTC One using AULRO mobile app

[Wicks89]

Thanks for your replies guys,

I have a new belt and armed with some knowledge will report back on what's going on/any solutions.

[Wicks89]

Guys,

For anyone reading this seeking the outcome I've solved the problem. The alternator was to blame.
I spoke to the guys at TR Spares and they said that the misalignment was most likely due to failed water pump bearing, they said water pump as it was most common.
I went back and pulled the fan and shreds of belt and sure enough the water pump was fine but the alternator (vacuum pump) pulley was buggered.
The easiest way to tell is to pull or push on it to move it out of alignment.
I removed the vacuum pump and could hear loose ball-bearing rattling inside. Cactus.
Unfortunately you cant just get a vacuum pump, you have to get the vacuum and alternator assembly. 550 bucks. Ouch.

The failure I think is attributable to the alternator mounting bracket breaking a few months ago making the belt pull on the pulley out of it's intended plane, probably buggering the bearing.

thanks for your help, the soot was from the belt too, which really was the most telling as to what was not spinning smoothly.