DIY: Replacing the Bearings in the Idler & Tensioner Pulleys

beware of torque specs.. I set my wrench to 10lbs to test, went fine.. then set to the 27lbs and it snapped. So then had to replace the tensioner itself as mentioned above.

 

Good to know and being its threaded into aluminum probably wise. Maybe go with 20 ft/lbs and a drop of blue loctite..

Had you considered using a helicoil insert to replace the stripped threads in tensioner??

 

the bolt snapped inside the tensioner itself. No way to get an extractor or anything in there. Had to pull and replace the whole thing.

 

I though maybe it striped the threads

What the f!!! That's a 10MM diameter bolt. The reccomended torque on a 10 mm/class 10.9 /course thread bolt that size is 49ft/ lbs when NOT used in aluminum of course. It should never had snapped at 27ft/lbs

 

I agree. It may have been stressed over the years.. as it had seen a lot of shit. just be careful...

 

So I planned on just swapping out the pulley but when I was (left hand)tightening the bolt on I somehow over torqued it and now the bolt and pulley are at an angle, so it looks like I have to go all the way and replace the tensioner as a whole. I was using a torque wrench and way below 27 ft lbs.

 

Some torque wrenches only work in the standard direction. They will ratchet in the other direction to loosen standard fasteners, but they may not actually be measuring anything.

 

From direct experience I can tell you you don't want to replace the tensioner pulley in the 2nd gen with the 36174 pulley. Just looking at the picture you can see how much wider the bearing is compared to oem bearing. The issue is you lose about half thread engagement on the bolt. That can lead to stripping the alum threads in the timing cover.

It is possible a new redesigned tensioner accepts this pulley. If someone can confirm this, I’ll update the thread.

 

If you are worried about the integrity of the old tensioner pulley bolt this is the part # for a new tensioner pulley bolt...

https://parts.scarboroughtoyota.ca/...e-Cylinder-Head-Bolt/66252490/90105A0279.html

 

Since the 36174 pulley comes with a new bolt, is this bolt the same length as the original or longer to compensate for the additional width?

 

@babylon5 It’s been well over five years since I dealt with the pulleys. I don't recall if a bolt came with the new bearing. I had an AC Delco bearing - same part # as Gates. If a new bolt came with it, it measured the same length or I would have noted the difference because I did ‘dry fit’ the bearing into the tensioner and noticed the loss of thread engagement. A commenter in Amazon notes a bolt does come with the bearing but it is regular threaded, not reverse. No size is given.

 

How exactly did you go about this? Did you remove the entire bracket and drill the bolt outside of the truck?

 

I removed and replaced with a new tensioner. I was able to unbolt the alternator and ac compressor and move it enough out of the way with the hard lines still attached to do the swap.

 

I agree, removing the tensioner was a pain in the butt. There are some good YouTube videos about it. Remove the Alternator and then move the AC comp out the way.
I wish I read the above notes about torque wrenches possibly only working one way. I think I nearly broke the bolt off the new tensioner.

 

Thanks Chuy, going through this right now with my truck. Appreciate all the part numbers, and I printed it out!

 

I just finished replacing my idlers and pully on my 2006 Tacoma Pre-Runner 4.0 V6 Double cab. There is some debate on this tread about which bearings are an exact replacement. The bearings I removed (OEM) are KOYO 6302RMK made in Japan. Idler #1 has 2 of these bearings stacked and Idlers #2 (both) are single bearings.

I found these exact bearings online the first link in EBAY so authenticity is not guaranteed $22.90 per bearing. https://www.ebay.com/itm/1665107798...9F8m5lmgdvK6XRFRncDkIXoA==|tkp:Bk9SR8j50sG5Yw

HOWEVER, the ebay seller on the above link is the same as the seller on the next link which I believe to be an authentic dealer $19.80 per bearing. https://rodavictoriausa.com/product...g-for-toyota-lexus-idler-pulley-10x42x13mm-2/

I hope this helps clear up anyone's confusion.

 

@haasume --

RodaVictoria also sells a cheaper $14 version of the same bearing, both on their ebay store & their main website.

I ordered 2 of the cheaper ones and will try one of them in my idler pulley #2 near the alternator.

Of note, these are advertised as being 10mmx42x13mm, whereas the "KOYO / Jtekt" original bearings you linked are in fact 10.2mm ID x 42mm x 13mm. I verified same with a pair of Mitutoyo digital calipers when I pressed out my old KOYO-original bearing. (Actually measured at 10.25mm.)

The only reason I can think of that the difference between a 10mm and 10.2mm bearing ID is that the extra 0.2mm of play (which is plainly visible & audible as a "click" sound when hand-testing the bolt through the original 10.2mm ID Koyo bearing) is to allow for heat expansion of the bolt at full engine operating temperature

(Coefficient of thermal expansion of steel is ~0.00016383 mm / mm / degree F. Figure a max engine oil temp of 240ºF worst-case, 240º - 60º = 180ºF temperature delta since bolt installation.

180ºF temp rise x 9mm bolt shaft diameter x 0.00016383 = 0.26 mm of expansion, which is just about the additional amount of I.D. in the non-standard 10.2mm ID Koyo bearing.)

https://www.ebay.com/itm/165021641745

I'm posting a screenshot here for when that eBay listing eventually gets removed or the URL changes:

 

@GilbertOz I don't think the .2 mm difference will matter much. Once the pulley is bolted down it is not going anywhere. As a precaution, the pulley can be positioned in the direction of force to be acted upon it. Once torqued down, it will not wiggle around.

 

M10-1.5 LH x 38mm is factory. You will want a 44mm with 36147 to get the same thread engagement.

 

Lots of great info on here and I want to thank @Chuy for remaining active in this thread and providing us member with his time and help. I’m about to start this project and I just want to make sure I’m ordering the right bearings to press into my idler pulley from the following links.

If I order 4 of these bearing would I still need any adapters or reducers? For idler # 2 and 1

https://rodavictoriausa.com/product...g-for-toyota-lexus-idler-pulley-10x42x13mm-2/

for the tensioner pulley bearing which one is the one to get NSK, Nachi, or Koyo?

https://rodavictoriausa.com/producto/5203-rs-3203-rs-nsk-sealed-bearing-bd17-31-dum8/

https://rodavictoriausa.com/product...40x17-5mm-double-ball-bearings-5203-2rs-3203/

https://rodavictoriausa.com/producto/5203-rs-koyo-sealed-bearing-bd17-31-dum8-3203-rs/