WHO WOULD OF IMAGINED !! WOBBLING IDLER PULLYS NORMAL !!

This truck is garage kept and so far has not even been in 4WD. Just use it for the longer highway commutes and occasionally tow a trailer that is way underrated for the towing capacity of the vehicle. Most idler pulleys are sealed bearings as these are. In the busses that I service the bearing seal can be removed and the bearing has access for new grease, then reinstall the seal. Adds lots of life to the idler pulley.

 

Just a jest .

 

Sometimes a pulley will be designed with a crown center on the belt face with a slip fit between the ID of the bearing and the OD of the shaft.

This design allows the idler pulley to self-center on the belt. There are numerous measurement to allow a serpentine belt to run over multiple pulleys without derailing. This type a pulley allows some leeway in the critical alignment.

The only way to know is to remove the belt and physically measure the play......axial or radial.......otherwise.....just suck it up, cuz you are guessing.

 

This was my initial guess. Based on the shape of it, I'd say there's a pretty good chance this is the case.

 

I'm good at the sucking it up part. So far - nobody got on here stating that their Tacoma idlers run true. Therefor, my deduction is they are designed to wobble and spend their life trying to find center. I always thought that the grooved pulleys kept the belt in it's proper place as long as they are aligned and added more surface area for the belt to grip that particular option of the vehicle. Still it seems stupid to me with todays technology that Toyota lets folks look at a running engine and say - hey I think you got a bad Idler pulley or two - not knowing it was their plan all along ???? I still say - if yours do run true - get to the dealer and complain cause apparently it's not supposed to be that way. I'm putting this to rest now in search of other brilliant ideas. Thanks for the kind inputs here as usual. As long as it is common among the Tacomas I'm not worried at all. Toyota still makes quite a product !! That's a fact !! Regards Scott

 

ernscott, thank you for posting this, as I was searching for this exact information. I noticed mine wobbling today, and even when under belt tension you can grab it and wiggle it and feel the slop in it. Iv'e been a mechanic for 45 years and can't believe this is acceptable, or that it lasts. It's really astonishing to me how minimal the engineering quality standard is on these Tacoma's, but how well they hold up. I was about to bring it to the dealer to have them replace it, lol. I guess you saved me the trip.

Mike

 

Update; I brought to dealer for inspection, and the tech is replacing the pulley. While looking at it further, I realized there's a second idler on the passenger side which is not wobbling at all. So that alone is evidence to something wrong. Going to take a few weeks to receive, and I'll provide feedback once replaced.

Mike

 

Looking forward to the update. Just replaced my serpentine belt today and the pully to the left of the alternator is visibly moving while running and off there is a good amount of play. Mine is a 2017 with 80K on it.

 

https://www.tacomaworld.com/threads/serpentine-belt-roller-wobble-56k.788232/

 

Well I’m a believer in that it is normal wobble. Brand new factory belt; factory pully and still a little wobble. No noise. The other made no noise either. I’m gonna check it off as replaced and it is what it is.