Drive belt jumping off

[keef]

I have had my drive belt jump off 2 times now (500 miles in between), this time shredding the drive belt. On examination I noticed that the belt tensioner was stuck hard right (de-tensioned). When I put a spanner on the pulley it sprung back to the left into the tensioned position.

All the pulleys rotate fairly freely but do have a 'tick' when rotating.

Does any one have any idea on what could be causing this to happen?

 

[Auberon]

May have been pulled to that position when the belt broke but????shouldn't happen but it may be a one-off. That belt breaking is one heck of a shock. If it's free and doesn't feel notchy in its action now you may well be ok.

Have you checked the alignment of the pulleys with a straight edge or a laser? 'Tis a hard place to get the average straight edge into.
The tick, is one thing I would investigate with a mechanics stethoscope. Indicates a bearing coming into question. As you probably know,the only way to go about replacing just the idler failing is to trace around the belt driveline with a stethoscope. Have found often to check pulley alignments a builders laser set to display a straight line and a cigarette paper held across the edge of the pulleys is a useful indicator - you can glue it onto a dowel for reach and see the red (or green) line clearly - even a bit of spit on the end will saliva on the cigarette paper will glue it to the stick for reach.
I see you've had no answers so I help this helps.
Cheers
Auberon

 

[yellocoyote]

Have you checked to see if the pulley spins freely and is not getting caught? Also, you might consider replacing the tensioner if you've already found it to be causing problems.

 

[tommudd]

Yes on the above regarding replacing the whole tensioner
it may of been going bad which caused the belt to go in the first place
Its fairly cheap to do. New tensioner comes with pulleys attached, add anew belt and be done

 

[Auberon]

I keep forgetting how much cheaper parts like tensioners, belts and oil are for you blokes. Sorry.
Here you sell your soul to do a job like we are discussing in this thread.
Yes, we are importing madly and try not to go near Jeep dealers for supply if we can help it at all but RH drive complicates this sometimes: eg:The best I have ever bought Mobil 1 for (10 litres) is 80AUD + 10%tax.
Aaaaah.....The peculiarities of the world.
Cheers
Auberon:shrug:

 

[Mikejeep]

http://www.ifsjeepers.com/phpBB3/viewtopic.php?f=24&t=123

 

[javert]

Sounds to me like you need to replace the OAD on the alternator. Many people do not know that the alternator pulley (OAD) must be replaced with the correct style when worn out. The OAD is much like a set of brake pads, it wears out. If the OAD is bad or if you have the wrong style, your CRD will eat tensioners and you will have belt issues for rest the CRDs life.

The CRD uses a Litens Style Overrunning Alternator Decoupler.

www.decouplerpulley.com.

Javert.

 

[Auberon]

Gates emailed me with info re their new ribbed belt alignemnt kit.
Nice - laser and target designed to sit into the ribs of the pulleys to check alignments around the system, belt wear indicator (but these are free from Gates - or were a short while ago and a few other bits'n pieces that will check belt tension acurately so if your tensioner has failed you would know for certain.
They also have a "Proper" belt wear indicator to sit over the belt to permit crack counts per unit length and wear etc

$ unknown.

Hope you have it sorted.