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, on the blue room, there is a write up about how to properly clean your bearings. 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"
(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.
Two Upper Pulleys (#2): 36173
One Lower Pulley (#1): 36174
Serpentine Belt: K070834
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.
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.
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.