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Idler Pulley/Bearing Failure, what to do:

296K views 248 replies 116 participants last post by  darksidetourist57 
#1 · (Edited by Moderator)
I know this has been discussed in many threads but it got difficult to sort though all of it so here is what I could gather.

First, THANK YOU to everyone that has been putting in so much work to figuring all of this out over the past 4 years!

OK, here goes...

As most of you know, the factory Toyota bearings inside the idler pulleys on the FJ are not sealed... go figure.

What does this mean?
Well, if you do any type of water crossing or playing in the mud, it could potentially get dirt into these bearings and sooner or later they will start to go bad.

How do you know if you have a bad bearing?
The first clue is a 'screeching' noise coming from under the hood, usually a couple of days after a water/mud crossing. Most likely, the noise will start to get louder and louder with time and RPM. In some cases, the problem has been with other pulley bearings as well, such as the alternator, power steering, etc... however, in over 90% of the cases, the bad bearing(s) will be in the idlers (usually uppers).

How to prevent your bearing(s) from going bad?
Next to staying out of water and mud, there really isn't a sure way of keeping the pulleys from going bad. One thing that has worked for sometime is to 'wash' down the idler pulleys after wheeling. Take a small water bottle and punch a hole into the top so that you can 'squirt' the water at the pulleys, usually works very well. Also, here is a write up on how to properly clean your pulleys:https://www.fjcruiserforums.com/forums/how-technical-articles/39749-pulleys-proper-cleaning.html This requires disassembly of the Serpentine system.

OK, OK, what bearings, in what pulleys are we talking about here really?
There is some confusion, not only on FJ forums but also in the different manufacture year manuals, as to what idler is 1, 2 and 3, so for the sole purpose of this write up, I will stick to the terms, 2 uppers (Pictured as #2 ) and 1 lower (Pictured as #1 ).

In this diagram, taken out of the 2007 FJ Cruiser Manual, the 3 idler pulleys are circled in red along with the belt tensioner circled in orange. All 4 of these pulley bearings are not sealed and could potentially get damaged in a water/mud crossing.


What to do if your bearing(s) are bad?
If you still have warranty on your truck, take it in! Usually the dealer will replace the idler pulleys at no charge under warranty.

If that does not work, or your out of warranty (like me) then I'd suggest at looking for sealed bearings/pulleys.

The factory non-sealed pulleys are Koyo.

ACDelco, Dayco, Gates and Goodyear, all make sealed idler pulleys for the FJ or at least they claim to. After looking at some of the aftermarket pulleys, it appears that most (if not all) use NTN Canada Bearings. If its the same bearing for all companies, I do not know.

One issue I have run into personally, is that the aftermarket bearings require a sleeve (bushing, spacer, or what ever you want to call it) in order to work properly on the FJ however, some (like ACDelco) make an incorrect sleeve and others do not have one at all...

The correct sleeve for the upper, should be around 0.405" ID
(I do not have the measurement for the lower at this time)
In any case, there should be almost no play on the bolt what so ever!

So which pulley(s) do I buy?
Great question and really what this thread is all about! My recommendation is Gates! Why, I have had good luck with Gates products in the past and from reading a lot of threads about this issue on different FJ forums, most agree that Gates is the better choice.


Gates:


Two Upper Pulleys (#2 ): 36173 Product Detail Page
One Lower Pulley (#1 ): 36174 Product Detail Page
Tensioner: 38411 Product Detail Page
Serpentine Belt: K070834 Product Detail Page

[Added by Winterpeg]
NAPA part numbers:

Here are the part numbers for the NAPA pulleys....
drivebelt idler pulley, lower - UNR 36174 - $ 112 CAD
drivebelt idler pulley, uppers - UNR 36173 - $ 93/each CAD
drivebelt tensioner assembly - UNR 38411 - $ 184 CAD

American napa uses NBH as the line code rather than UNR
The actual numbers are the same.

Where to Buy?
You can get the parts where ever you want but the best deal so far that people have found is from RockAuto. Their prices are great and with one of the Coupon Codes from RetailMeNot you can safe an addition 5%.

Tensioner Pulley Warning!
Apparently the upper pulley part number cross references as the pulley on the tensioner and some have ordered just the pulley instead of the entire assembly. After further research (not by me) it turned out that this was not the case and that the pulley did not work. Apparently the spacing and dimensions are incorrect. My suggestion is just to replace the entire tensioner assembly and avoid any potential damage that could occur by installing the wrong pulley.

How to determine which one is bad?
When the engine is running, carefully look at the pulleys and see if any of them is 'wobbling'. If that does not work (and usually its not very accurate), with the engine off, undo the tension on the serpentine belt and spin each tensioner individually. Usually you can tell which one is bad by a rapid stop, a wobble, squeal or anything out of the ordinary.

Disassembly:
If you've never worked on a Serpentine System before, please have someone help you that has. It is not complicated by any means however, any misalignment of the belt could cause serious damage to parts, you and the engine. Also, be careful working with the tensioner and around the radiator fan!

I'm not going into to much detail, anyone working on this should know how to do this.

To loosen tension, just rotate the tensioner counterclockwise (to passenger). There is a little loop at the bottom you can put a allen wrench in to hold the tension while your working.

The pulley bolts are fairly tight but should break loose with a good wrench or breaker bar.

Here is a picture of my two upper pulleys, the black ones are the new Gates (notice the sleeve that comes with them on the left side) and the silver ones are my old factory ones (Koyo):


On the factory setup, the two upper pulley bolt actually has a 'dust cover'/washer on it. I did read that some did not install it again but after a good cleaning and taking some measurements, I decided to put it back in. The center riser is a perfect fit on the sleeve so it will not damage the bearing and the OD is just perfect to sit inside the pulley, here is a picture of the parts:


At this time, I have only replaced the two uppers, mainly because my tensioner and lower idler are still in good condition and unfortunately both are currently on backorder. I will update this thread once I can get my hands on the lower and a tensioner.

EDIT: For Tensioner Pulley Replacement please refer to post 3 in this thread by 5Greens: https://www.fjcruiserforums.com/forums/maintenance-tech/127154-idler-pulley-bearing-failure-what-do.html#post1888318

Installation:
Do what you just did in reverse. Seriously tough, it is very easy to loose the sleeve or washer during the process. My recommendation is to put it together outside the vehicle (insert sleeve into bearing, lay the washer on top, insert bolt). Once in place, tighten by hand until snug (make sure that the bolt is 'inside' the pulley to confirm that the sleeve is set in all the way).

Now torquing to 'factory specs' is an entire debate in itself! Apparently there are variations in the different manufacture year manuals.
My FJ is a 2007 and out of my 2007 manual this is what I got:




Rout belt, double and triple check to make sure that the belt is perfectly routed and seated on all pulleys. BTW, if you did not replace the belt (I'd recommend replacing if you have more than 70K on the truck) please check for damage before installation!


To conclude, part numbers and torque specs (2007 Manual):


Again, I will update with any information I and/or others have.
 
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#70 ·
I am still unclear on what pulley is needed to replace the tensioner pulley. I understand that you can purchase the whole assembly and just use the bolt, but could I also just use one of the upper pulleys for this purpose? I see that the only difference in the pulleys is .3 difference in width (upper pulley smaller than the tensioner pully) and was wondering if this would cause an issue? Would I be better off just paying the extra for the tensioner assembly?

This is my first post, but have been combing the forum and using the wealth of info for a while! Thank you for all of your help!
 
#71 ·
Not 100%, but I think the lower idler pulley is the same as the tensioner pulley.
 
#72 ·
#73 ·
Replaced my serpentine belt tensioner after hours of work to find my belt was still squealing and the belt riding on the inside of of the pulley chewing it up after installing a new belt, all new pullies, and a new belt tensioner mechanism. Took quite awhile!

Turns out it was the damn new Gates upper No 2 Idler Pulley sat crooked causing the belt to be out of alignment!

The backside of the gates pulley is an entirely different design than oem. The Gates doesn't seat properly on the timing cover mount and gets sideways to the naked eye. I even uninstalled and reinstalled it a few times to make sure it was installed properly with the shady insert.

I say no Gates pulley for the upper . The gates isn't black anymore either so maybe it's the ****ty original design again?!

I reinstalled the dirty oem pulley and she's straight, finally! Headed to Toyota dealer for a new oem pulley. They said the design changed on it as well. Maybe they are sealed now? :cheers:

I wish I went all oem. Oem is the same price as Napa for the suspect gates pullies, $60 each

Great info/advice on this thread :cheers:
 
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#75 ·
Yea if I knew how to tell by looking at it, I would know for sure;) I should have taken pics so that someone with more knowledge on bearings could advise.

I can't think of any good reason Toyota would have changed the design other than to address the issues with the original, which all seem to be related to unsealed bearings.

After I go fishing today, I might remove and return the other Gates pullies if the stealership is open.

I'll take pics this time.

If anyone orders the updated Toyota pulley, don't forget to buy the new, required outside washer separately, so they spin and track properly (about $3). I think I was at $63 total for one pulley and washer.
 
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#76 ·
Just knocked mine out yesterday...all 3...new belt...no tensioner change (yet)
The silence is DEAFENING!!!
Haha...Best hour spent under the truck this year.
 
#77 ·
Great thread!
Took the FJ offroading last year and since then Ive have a super bad grinding noise coming from the front end.

Ive changed the NO1 and NO2 idle pulleys and have to do the tensioner pulley.
I still have the bad grinding noise, if i change out the tensioner pulley setup and it still has this noise, what else can it be??

Thanks
 
#78 ·
There are 3 idler pulleys plus the tensioner pulley. As well, sometimes the alternator bearing makes noise if driven thru deep muddy water. You'll have to isolate the sound with a mechanics stethoscope (metal rod) or similar.

DEWFPO
 
#82 · (Edited)
I would do bearing in an alternator if that was what had failed. Take into consideration TIS (time in service) of the alternator and available replacements.

I had an alternator on a Chrysler Town N Country that was what I thought a bad alternator bearing. I could hear it with a Christmas wrapping paper tube (it happened to be mom's car at Christmas). I found one at the local Napa and some discount auto supply store.

Before I started, I did a quick google and got a youtube video so I could see how to best approach and if needed any special tools. It turns out that there is a special pulley on the alternators that can go bad.

This pulley is a fuel efficiency thing. A one way pulley that does not cause drag on engine when you take your foot off the pedal. Known as an ADP (alternator decoupler pulley) I have no idea if this is installed on our vehicles, someone please advise. I don't see FJC listed on this Gates ADP flyer, but it just means Gates is not offering one for sale at the time of the printing. See Below

I was able to replace the pulley alone for about 130 as opposed to three hundred $omething for the rebuilt alternator with the "your gonna be replacing these parts for the rest of your life" warranty
 

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#90 ·
If when you spin the compressor pulley by hand, if it is rough, you can just change the pulley without removing the compressor or evacuate the charge of the system. The pulley assembly has the bearing right in itself as well as the compressor shaft has a bearing also. Remember that the pulley has to free wheel when the A/C clutch is not engaged.

There is a pulley removal kit available for rent at some autoparts stores. Basically you buy the used kit and return it when done. You should be able to do the removal and replacement while still mounted to the vehicle.

Take it to an A/C shop and have them hook it up to the gauges and look at the operating pressures. Also try to figure out how many miles on the A/C compressor to determine if it would be worth your while to just change the pulley.

How many miles on the vehicle? What year?
 
#95 · (Edited)
This is the Toyota Part Number: 884102F010 for my 2010 FJ cruiser
It is as expensive as the compressor without the clutch 475USD plus shipping

That being said, 475 is for the OEM part, I am sure there is an aftermarket part available.

That is the trick though, you want to find a compressor clutch assembly.
Now, the aftermarket compressors I saw for sale here had the clutch assy included. You might want to consider getting a compressor, removing the clutch and installing on your truck, and keeping the compressor sealed up and ready on the shelf.

NOTE: Make sure you order your clutch for your make and model. I saw on Toyota parts they said there were possibly different parts for different years as they changed some components.

What year is your rig?
I just googled just "Part Number: 884102F010" and found it for 419USD

For 2008 Part Number: 8841035430 is 260 USD from Toyota Parts Direct
 
#96 ·
You could try spraying electrical parts cleaner between the A/C clutch surfaces and see if that quiets it down without pulling the clutch, but you risk cleaning the front bearing of lubrication as well. Might be worth a try if your planning on pulling it off anyway.

DEWFPO
 
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#97 ·
I just started to get a whine with my Fj haven't looked into which it is coming from. My question is how bad is it to drive with a bad bearing?

I don't want to mess anything up but I won't have time to do the work for a few days.
 
#98 ·
Usually it will just keep making noise with no issue. However, I would look at the pullies with the engine running and they shake, or are ****eyed, I wouldn't drive it another foot without replacing. Or if the belt is visibly worn or roughed up it means a pully isn't spinning properly and you want to replace the belt and pully immediately
 
#99 ·
Just ordered the Gates idler pulleys and new belt for mine. It's not screeching yet but has had a slight grinding noise since dring through some water earlier this year. I'm hoping its one of the idlers but we will see. I should change the belt anyway and since I am in there its worth changing the easier pulleys.
 
#100 ·
need some help guys, I checked my belt and I took it off and it looked fine so I put it back on and now its squeeling on and off, all the pulleys were smooth and the belt was fine......any advice????? should I loosen it up and re-route it again? or just change the belt out??? I've never been through water or mud.......
 
#101 ·
Did you tighten or loosen the pulley mounting bolts?

Re-torque the tensioner bolt to spec?

The torque specs have to be spot-on or the pulleys don't spin properly at the correct RPM. The tensioner bolt can loosen while releasing the spring tension.
 
#107 ·
Took my fJ through some pretty heavy mud/swamp/water to the point where she was in complete suction up to the top of tire in front. Didn't plan on that particular puddle. Noticed water spurting out as fan was partially submerged... not good. Got a tow out and even after cleanup noticed mettalic whining noise when RPM increase. Scared the crap out of me thinking I might have done irepairable damage to engine or water in air intake. Thank God! it was just the idler pulley/bearing... this was something simple and relatively cheap to repair, horrible sound though that if you don't know any better will give you the chills. AWESOME article bro! I'm sure many others will feel much better when they discover this bad component is usually the suspect. Thank you!
 
#109 ·
Quick question? Is the belt tensioner suppost to move slightly when the engine is running the belt? When I change the belt I move the bolt in the tensioner the opposite (wrong) direction slightly?!?! Once I notice I turn it the opposite direction till the tension disengaged. Just was a bit worried I messed it up? The tensioner when running shows a little bit of movement when running and the top pulley is a bit of a wobble? Just want some input thanks!
 
#110 ·
Found the same pulley on Amazon just copy and paste the number 36173 for the upper into the search and it comes up. The price is $26.09 each. They are $77.16 with overnight shipping, which is cheaper than buying one upper from Autozone and you will receive it faster as well.
 
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