DIY: Replacing the Bearings in the Idler & Tensioner Pulleys

@PMK There is an app by World Bearing Association that scans the box and determines if the bearing might be fake or not. Your option whether to submit a claim for further review. https://www.stopfakebearings.com/

 

Two of the three pulleys had QR codes. One did not have the QR code. Checked the two and those pulley assemblies are legit.
Risky as some might consider it, I will still run the pulley without the QR code. While it could be faked, it does have Koyo sealing tape and iridescent label. Also, they took the effort to stamp part number info and more into the pulley face.
When the tensioner pulley bearing arrives, I will check that if it has a QR code.

 

The replacement bearing for the tensioner, I specifically ordered a KOYO. The bearing arrived from Rodavictoria and had no QR code on the box. Again the embossed reflective image was on the box and gave me no concern about the bearing.

The tensioner bearing is not inexpensive. The cost of the one KOYO tensioner bearing was slightly less than the cost of three KOYO replacement idler pulleys. All idlers and the bearings were purchased from EBay.

A few years ago, I did purchase a new serpentine belt from Toyota. I had left it in the original packaging, stored in a plastic shopping bag, and stashed in a storage compartment under the rear seat. I used this new oem belt to complete the replacement of doing this task of idler replacement. The belt removed, I put into that oem wrap and kept as a spare, along with the belt routing diagram, under the back seat.

Removing the original belt was easy. Removing the idler pulleys, also was very easy.

Since the location of the idler determines which pulley is installed where, I got lazy and did the removal and reinstallation one by one.

The matching pair of new replacement KOYO idlers differed from oem in that the engine side of the steel pulley had a slightly smaller opening. This did not allow reusing the thin oem step washers. These were omitted and the idlers installed without an issue. The steel pulleys smaller aft side opening closes the gap between the aluminum engine case post area, likely providing a similar and possibly better dust diverter for the bearing. I suppose, if a person wanted, the oem washers OD could be reduced and the washer retained.

The lower idler was a direct match.

Regarding the tensioner idler pulley bearing, this had to be pressed out, and the replacement pressed in. All this was done with the small 10 ton press and correctly sized flat edge sockets ensuring no pressure was applied to the inner bearing race while installing. Removal was no big deal, but did require a bit of pressure until the old bearing released from the pulley with the typical “pop”.

At a guess, start to finish took about 1 hour.

As a suggestion, obviously double check your belt is correctly routed and seated properly on the pulley grooves of the driven items (alternator, water pump, power steering, crank pulley, and so forth, before starting the engine. A simple check also is the as the belt goes over an idler pulley, the belts smooth side runs against the idler.

All assembled, engine was fired up, as expected no noises or concerns.

Thank you everyone that offered up info regarding accomplishing replacement of the idlers and bearing.

My oem pulleys and belt had just under 90,000 miles and almost 13 years old. None had failed or squealed, and the belt has no damage. Spinning the removed pulley bearings, while not yet rough, you can hear they were starting to have dryness and wear. Hopefully this new set will do as well.

 

@PMK Good idea putting the belt diagram in the car - never thought to do that should the belt come off for whatever reason on the road. I’ll take a pic of it for now, but will print a copy and tape it under the hood.

I replaced my water pump this past weekend, in 100 degree weather, and tried routing the belt without the diagram and didn't quite get it. I have 50K miles on the after market pulley bearings (Nachi and SKF on idler 2; 2 SKF’s on idler 1; Nachi on tensioner) - they all spin smoothly and none had any play. Only the water pump bearing had some play.

 

There are (were?) a few folks here and on the internet in general selling belt routing stickers for the 1GR-FE. I happened to grab one from someone on FB market place. Stuck it under the hood and sharpied in the direction of the main crank pulley

 

Got the new Nachi bearing pressed into the tensioner pulley last month. I was surprised how tight the press fit was, but otherwise it was a smooth process. The old one still felt smooth enough at ~101k miles, but glad to have it done for peace of mind.

 

For you guys that have swapped bearings in the idlers.. I just want to confirm that these replacement 6302 bearings (x2) will work for this double bearing setup in the lower idler. The OEM bearing inner sleeve is proud on both sides of the bearings and I'm wondering if the spacing it creates when bolted up is critical. If I'll need a spacer if some sort. Etc All of my research, part numbers, and ordering has come from this thread.

EDIT: I see it now.. 1MM spacer/washer needed but no ID adapter/inner sleeve is needed with theses newer 6302RMX bearings.

 

@XPOTRPR With the RMX bearings that have the 10mm ID, no spacers are needed. However, you need two bearings pressed in on idler #1. No spacer needed between them, just make sure you press in on the outside of the race.

 

Correct. I'm good on all that, its the inner sleeve that sticks out beyond the bearing race face.. that protrusion.. I need to use a 1MM washer to compensate since the RMX bearings dont have that extended portion. I re-read through the OP and found that bit of info. I'm going to find a washer that fits under the OEM dust cap as well so I can re-use those.

OEM pulley and bearings. KOYO 6302RMX. 10MM ID x 1MM thick washer. OEM dust cover/step washer.


washer on top of new Koyo 6302RMX bearing to match height of OEM bearing with extended sleeve.



OEM dust cap on top of said washer.



This washer is slightly too large on the OD to fit under the OEM dust cap. I plan to source another washer with the same 10MM ID and 1MM thick, but that will fit under the OEM dust cap.

 

@XPOTRPR I don't think that pulley/bearing combination is OEM. On my 2nd Gen, none of my pulleys had a center insert. All the bearings except the tensioner had 10mm ID.
Is your OEM bearing a one-piece, or two bearings pressed in?

 

its 2x 6302RS bearings on a sleeve. I just pressed them out. Its been years since I replaced any of these idlers, maybe this is one of them. So you're saying I dont need the 1MM washer to match the previous setup with the sleeve? and or dont need the dust caps? I'm going to just press these 2 RMX bearings in and go from there.

 

2x Koyo 6302RMX bearings pressed in.

 

all engine Idlers and Tensioner bearings replaced. I also replaced the bearings in my S/C idlers and tensioner.

old



new

 

@XPOTRPR Correct, you don't need to include the spacer. The 1mm washer/spacer was actually meant to be placed behind the pulley to increase contact between the timing cover boss and inner bearing race. It appears you used the spacer to make up for longer length of the insert which could have been shortened with a grinder. The insert is used to center the pulley. All bolt pressure goes through the inside races of the bearings. I will clarify this on the writeup. I would add the dust caps as long as they don't rub on the outside of the bearing races.

 

I know what you're saying.. and understand how the sleeve vs races of bearings work.. I guess I'm not explaining well enough. I need to match the spacing on the Idler #1 pulley like how it came apart.. as the rest of my supercharger idler assembly is mated to that pulley and the spacing for the blower belt need to be just right. As of now, without any type of spacer.. it puts my supercharger (its a stack up) out of position. I need 2x 1MM washers/spacers (one on each side of the Idler #1 bearing) and then it will be in line. I'm not sure why nor can I remember if my Idler #1 pulley was replaced (non OEM). But.. what makes me think it is OEM, is that it puts all of my pullies in line, supercharger included. All I know is what needs to be done.. so finding hardware is what I will be doing. The ID's and OD's of all the new bearings are fine, every other dimension is fine, its just that Idler #1 double bearing setup.. the sleeve that makes that bearing longer overall on my old one, compared to the new bearings.. that's the issue. Dust cap or not, the overall length when bolted up, it too short. I do appreciate the help.. and I know I am probably butchering the explanations and making it worse. I'll try and snag some pics tonight.. if not in the morning.

 

By this do you mean the bolt bottoms out, or the pulley is too close to the engine? Or something else?
If the former, yes add a spacer or two to the front of the bearing. If the latter, adding spacers behind the pulley brings it out.

 

Yes. Everything starting with the idler #1 needs to come out. It needs a washer on the block side and one on the front side of the Idler #1. About 1MM or .040" each. That will put the blower idler pulley a total of about .080" farther out and in the correct position.

Pics for reference..
Idler #1 in place with bearing race up against the block.


S/C assembly spacer in place.



S/C idler in place



Grey S/C idler in position is too short and misaligned.



Idk if I missed something during all my research, or my idler #1 was swapped out sometime previously, (which doesn't make sense because it put all my pullies in the correct positions, so I'm assuming it's correct), or there's something different with my year/configuration than the rest of you guys, etc.

Regardless, I'll get the appropriate washers to space it correctly and be done. I'll just note it for my future reference. Everything else (bearings, part numbers) work fine for all the other pullies.

 

@Chuy
I don't understand what I've discovered while doing my belt tensioner. It calls for the 17x40x17.5, which I found; however that is not what I pulled out of the pulley. When I removed the bearings I found an inner spindle the bolt goes through and two(2) seperate single race bearings. I've pressed the bearing, but the inner spindle and reverse bolt is too long. I have a OEM replacement coming in but won't be in until late this week and have to travel for work. Any ideas or thoughts?


By the way, I can't thank you all enough for posting this kind of information online for all to use. Growing up, I watched and worked my dad on all his cars, when all we had to go by was the Chilton's and Haynes manuals.

 

@SpicyRedTaco11211983 I am not visualizing that inner spindle. Can you post a pic or two? You have a 2nd Gen V6? Cause the new 3.5 V6 may have a dual bearing setup in the tensioner pulley as I know the sedans do. Or you have an 4 cyl, for which I have no info as to it’s tensioner bearing, but will try and help out if you have pics if the bearings.

 

2020 SR5 V6