Drive Belt Tensioner not spinning after bearing replacment

[Verybadwizard]

Hello, Everyone

I'm hoping the brain trust can help me figure out what's going on. I have an early production 2004 with the 4in pully. I removed the drive belt tensioner pully and pressed in a new bearing. The bearing I pressed out was a NTN Bearing 6203LLH 17x40x12. I replaced it with Nachi Bearing 6203-2NSE 17x40x12. When I compare them side by side they look identical in size and shape. Yet when I put the pully back on the tensioner bracket the pully doesn't spin. I'm thinking the bearing isn't the right fit but maybe I missed something else. Maybe I didn't press it in far enough or I bent the pully? It looks seated and the pully looks straight/square (not warped) to me...

Thank you for any advice!

 

[hoser]

Well, if you loosen the bolt a bit and it spins, and the bearing is fully pressed, then likely the bearing is slightly a different spec than OE. Some kind of super thin washer could probably make it work but really, the tensioner is a wear item and should be changed out after nearly 20 yrs.

 

[abuck99]

I think I recall that there’s meant to be a spacer-it’s discussed somewhere on the forum.. Did you check to see if there’s one the bearing you removed

 

[Verybadwizard]

Well, if you loosen the bolt a bit and it spins, and the bearing is fully pressed, then likely the bearing is slightly a different spec than OE. Some kind of super thin washer could probably make it work but really, the tensioner is a wear item and should be changed out after nearly 20 yrs.

The tensioner was within spec. It was providing the appropriate amount of tension. The pulley just sits too close and rubs on the bracket now. The new bearing supposedly is the same dimensions as the old one but I guess not. I’ll try a different bearing but maybe I just need to get a whole new tensioner…

 

[Verybadwizard]

I think I recall that there’s meant to be a spacer-it’s discussed somewhere on the forum.. Did you check to see if there’s one the bearing you removed

There wasn’t a spacer that I saw. That’s something I was wondering maybe I dropped a spacer or something but I don’t think so. I guess I need to try a different bearing and if that doesn’t work a new tensioner.

 

[abuck99]

Here

Idler & Tensioner Pulley Bearings, Drive belt (AKA Serpentine or fan belt)

Hey guy's anyone found a good source for the bearing of the: drive belt Idler Pulley part # 16604-0F010. The Bearing in it is a NSK BD20-15DUL: Edited 9/24/2019 Is a drive belt pulley bad: Sound is first alter bearing of pulley(s) may be going bad. To make sure which are bad remove the belt...

forum.ih8mud.com

 

[TheForger]

Man if you can find a reasonably priced source for the bearings without having to buy 100+ let us know! Because it’s an absolute pain to get the tensioner assembly out since in shares a mounting point with the alternator.

 

[2001LC]

Hello, Everyone

I'm hoping the brain trust can help me figure out what's going on. I have an early production 2004 with the 4in pully. I removed the drive belt tensioner pully and pressed in a new bearing. The bearing I pressed out was a NTN Bearing 6203LLH 17x40x12. I replaced it with Nachi Bearing 6203-2NSE 17x40x12. When I compare them side by side they look identical in size and shape. Yet when I put the pully back on the tensioner bracket the pully doesn't spin. I'm thinking the bearing isn't the right fit but maybe I missed something else. Maybe I didn't press it in far enough or I bent the pully? It looks seated and the pully looks straight/square (not warped) to me...

Thank you for any advice!

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I've the 6203-2RS Nichi Japan, in my notes as a good fit. IDK if the -2RS matters.

• Make sure center race of bearing is seated over the pilot shaft of tensioner. Sometime while bolting pulley on, it's center race gets hung up on pilot shaft.

But a few things:

• You have the pulley with back stop. Which I like since bearing can not be pressed in pulley to far. Just make sure clean and bearing pressed squarely to the stop.
• Very important when pressing in bearing, to not press on center race. Doing so, may damage bearing. Check that bearing in pulley spins freely by hand, and silently before installing on the tensioner.
• It is possible to bend the pulley, but hard to do. They are stronge. If done it would still work, but wobble.
• Pulley has a separate protect plate/washer on front of pulley, that bolt goes through. It has a shape, that allows for pressure from bolt on center race only. You must use it (best protection for bearing seals), or a washer that only touch center race of bearing and bolt head. If this washer, presses on pulley, it locks up the pulley.
• I'm finding tensioner, that axis is off. The pulley may than ride on housing of tension, or belt may rub housing. These tensioner are shot and need replacing.
• Make sure center race of bearing is seated over the pilot shaft of tensioner. Sometime while bolting pulley on, it's center race gets hung up on pilot shaft.

Center Race of bearing fits on pilot shaft. Don't get hung up, on front pilot shaft. Seat bearing all the way on.

A shot tension with axis off. Belt rubs.

Gap from one side to the other different, indicating axis off. This was not above tensioner, which axis out of alignment was even worst (gap) than this one.

 

[Verybadwizard]

Thank you all for your responses. The tensioner assembly looks pretty good the assembly is not off its axis by much if at all. I figured out I bent the pully while trying to get the bearing out. I also tried the Napa bearing but it was the same effect it wouldn't spin when attached to the assembly. I found that the pully has a slight warp to it that makes it contact the tensioner assembly. I ended up replacing the whole assembly since I was doing a fan bracket job and was "already in there".

Moral of this story is be careful when pressing out that bearing. I was using a bench vice with wood at either end like demonstrated in the video posted on a different thread by 2001LC. Possibly my vice was to small and I wasn't able to line it up square enough. I also think that because I used a softer wood the pully and the vice indented at different points into the wood enough to not press evenly and that caused the warping. Those are my running theories at this point. I have put everything back together and it runs fine now. Thanks again!

 

[nissanh]

I too bent the pulley while pressing out the bearing: Glad you figure it out.