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Topic: Pulley Bearing Noise (Read 671 times) previous topic - next topic

Pulley Bearing Noise

When starting today I notice a squeaky bearing which sounds like it's from one of the pulley idlers.  We've got about 200 miles today so I'll keep a watch. Ideas?

Re: Pulley Bearing Noise

Reply #1 –
Do you carry a spare in case it fails?  You could pull the belt and rotate it by hand to see if it feels "rough" or has play in the bearing.

Re: Pulley Bearing Noise

Reply #2 –
Change the belt if you have a spare and see if the squeal goes away. I had the same problem recently and initially replaced the belt tensioner,  which didn't help.  Changing belts fixed the problem and  I kept the "squealer" as a spare.

Re: Pulley Bearing Noise

Reply #3 –
Randy,

IF, repeat IF only the bearings are bad, pretty easy to press them out and replace.  Most are very common bearings available at most auto parts houses.

But, particularly if this is an older tensioner, replace the tensioner complete.  In addition to bearing failure, they can loose tension and also loose dampening capability.

Here a good, short video by Gates Corp (who, btw makes some very good tensioners):

http://www.youtube.com/watch?v=uTLV5IU_IMM

Re: Pulley Bearing Noise

Reply #4 –
After an hour on the road noise is gone. Will likely replace tensioner at earliest opportunity. No record of prior replacement. And, of course it's Saturday!

Re: Pulley Bearing Noise

Reply #5 –
When we purchased our U300, the belt jumped around exactly like in the video above. After it ate a belt, I checked the alignment between the tensioner and the crank pulley and the hyd pump. 3 degrees off. The bearing was dry and made a whirring noise when I spun it but no rough spots so I just lubed the bearing. After lubing, the tensioner still jumped but alignment totally cured the problem. OEM tensioner is fine 60K later and the new Gates Green belt that was replaced at the time is also fine.

Don't know about the Cummins installation but Foretravel paid no attention at all to the tensioner installation/alignment on U300s with Detroits. The PO had lost several hydraulic belts while they owned it. Good way to lose an engine!

I always thought Gates video was a sales gimmick for tensioner sales. So, before ordering a new tensioner, check the alignment. Any wear on the edge of the belt is a sure sign of mis-alignment. The belt should also ride in the middle of the tensioner roller. The mount for the tensioner may be adjustable and the hydraulic pump pulley can be moved on it's shaft if it is not in alignment with the crank pulley. One crack per groove per inch is the max allowed before belt replacement. This is the most important spare you can carry on the coach. If it breaks, it will be a mile behind you so you won't have the part number plus, if you have a 8 goove belt, no auto parts store is going to stock it. Order online and it will be half the price too. Gates Fleet Green Stripe is probably the best. See my old post with photos for how to do the alignment.

Don't think about replacing the bearing as the tensioner is available for between $50 and $100 depending on your Cummins engine. By the time you are finished researching the bearings, order, take it to a machine shop, a new one will be at your doorstep. Check this link for model and price: cummins belt tensioner | eBay

Pierce

Re: Pulley Bearing Noise

Reply #6 –
Pearce,

I agree on just replacing the whole tensioner AND verifying pulley alignment.

I used the bearing replacement on a weekend when I could not locate the proper tensioner, but a local NAPA had the bearings in stock.

Re: Pulley Bearing Noise

Reply #7 –
Now is the time to replace them. It is a straightforward do it yourself project.

Here is our documentation: 
Replacing Hydraulic Pump Tensioner

Re: Pulley Bearing Noise

Reply #8 –
Quote from: wolfe10 –
Pearce,
I agree on just replacing the whole tensioner AND verifying pulley alignment.
I used the bearing replacement on a weekend when I could not locate the proper tensioner, but a local NAPA had the bearings in stock.
Wonder if all the bearings are the same? Don't happen to have a part number do you? Good example of being able to think outside the box when the tensioner is not available.

Pierce
 

Re: Pulley Bearing Noise

Reply #9 –
This from 2011:  .  Belt idler bearings (2 each): NTN 6203LU=  Fed Mogul BCA203-FF

No idea how universal they are.