Quick and hopefully easy question.. ..While cleaning the IC and some other spring maintenance I discovered my PS and AC idler-tensioner pulley has some wobble and bleeding grease. I just want to get the correct bearing the first time so I can get things back together. The idler pulley NSK bearing number is 6303DU2. I’ve found the NSK 6303DU on Amazon. I don’t have a technical background, is there any significance to the missing ‘2’ ?

 

Hahaha, I'm working on a friend's FD and am replacing the belts. I noticed his idler pulley was a little rough as well and Googled around on the bearing number.

I found a seller on Ebay with what looks to be the right one and I ordered 2 of them. I think the 2 at the end was some odd nomenclature that NSK doesn't use any more or something from what I found.

This is what I ordered -

https://www.ebay.com/itm/6303-DU-NSK...72.m2749.l2649

Probably won't have it for another week or so, however.

Dale

 

Thanks Dale! I remember seeing those too. NSK and 1/2 price of the Amazon one I found. And the OD looks to be right as well but like a dummy I didn’t get the ID. And the number on those was different still so I moved on.
I think I’ll pull the trigger on the Amazon one (and pay more than I should) just so I can get expedited shipping and maybe we can both update the thread with what we find out for posterity.
In any event i don’t think you can get just the bearing from MAZDA and the pulley assembly looks to be about $70.

 

As someone who used to buy $5000 SKF spherical roller bearings for industrial apps I would be wary of missing part numbers. Sometimes they were something important, others not so much. I know the stakes are lower here, but I replaced a bearing in my FC idler with a similar SKF before knowing better and it failed in short order.

Apparently the 2 is for a low grease fill. Probably due to the fact that this is a sustained high speed application... the fully packed grease may actually create more heat at high speeds, resulting in cooked grease.
https://www.ahrinternational.com/NSK_nomenclature.shtml

You could pop a cover off and scoop some grease out.

 

I called SKF Canada (the Napa Tech line) and they do not have a direct cross for the NSK. I used a SKF 6303-2RSJ and noticed grease "streaks" from it and after reading Alex's post that makes sense as the bearing is fully greased. Just some more info FYI.

Mike

 

I found this at NAPA while replacing mine not too long ago.

 

You can order just the bearing from Ray.

 

^Well duh. Never thought to check with him. Everything I’d read mentioned buying the pulley ‘assembly’. Lesson learned.

For posterity i ordered that Amazon NSK bearing. And props to Discount Bearings LLC, because within 30 minutes I received an email from them through Amazon double-checking the order. I gave them the OEM number and application and they confirmed a bearing with two seals and sent this....




From our exchange I guessed that the missing “2” on the end refers to the number of seals...one or two.