I just want to say that there's a very special place in hell for whoever designed that bolt location for the alternator bracket.

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I was hoping you could replace the clutch pulley without removing the alternator. According to the videos I've seen, the bolt on an "L" bracket in back of the alternator is very difficult to remove. Were you able to reach it through the wheel well? Does removing the left front wheel help with access?

Not at all. Get ready to cuss a lot and definitely use some good gloves. Finally got to it by going under the harness. Spent a solid hour trying to get to it from above and it's nearly impossible. My ratchet set has all 3 sizes. I used a half inch with a 3/8 coupling, 3 inch extension, and 2 inch long ratchet. If your ratchet is to short it won't get there but the wheel well gets in way if it's too long. There's about an inch of usable space. It's truly a jacked up spot. Used masking tape to hold the bolt to the driver to put it back on. Also that bracket doesn't fit flush with the alternator. There's a slight gap cheated to the outside by 1/32 or so. I just duplicated how it was on the existing.

The top #2 idler pulley was damaged. Not much, but it has a slight wobble now, so i ordered one. Tensioner is surprisingly okay. I'd taken the bearing out and cleaned and repacked. There was a drop of white lithium grease in the bearing a when i pulled it along with some accumulated dust.

Picked up a cheap reman from AutoZone until the
New pulley arrives. Still gotta work! I was on I95 when that belt snapped. The great news is there's a coolant hose directly above the fan, and the belt very specifically snapped into the clamp on that hose, knocking the hose off and draining all the coolant out while on the interstate.

I did put the new alternator on, reclamped hose and refilled coolant. No leaks that i can see. No oil leaking. Just praying the time it took me to pull over on the interstate didn't warp the head or blow the head gasket. Will keep checking the fluid for both for loss and for mix. Gonna flush coolant and change oil once the new pulleys get here to be sure.

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That’s bad news about the rear “L” bracket. I saw a guy on YouTube who jacked up the left front body (not the frame) to get to this bracket. Apparently, someone at Toyota didn’t check for access and glossed over it by simply stating in the FSM, “Remove rear bracket bolt to engine block.”

“Tensioner is surprisingly okay. I'd taken the bearing out and cleaned and repacked.” We’re on the same page … I’ve done that once or twice on other vehicles.

“… the belt very specifically snapped into the clamp on that hose, knocking the hose off and draining all the coolant out while on the interstate … (I’m) praying the time it took me to pull over on the interstate didn't warp the head or blow the head gasket.” I had to look at my T4R to see how that could happen. I think the tensioner played "snap the whip" with strands of your serpentine belt. I looked up the parts in this area. There are five (5) coolant bypass hoses and two (2) oil cooler hoses!!! I suggest using a small mirror to inspect the underside of these hoses for damage that might lead to a burst hose later. I'm guessing the No. 3 water bypass hose was knocked off. The oil cooler hose appears to be adjacent to the bypass hose ...

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Snap the whip is only good in the bedroom

Everything is okay so far. Still no oil or coolant issues. Might've dodged a very expensive bullet.

The fsm just says "remove bracket" lol. Wish I'd seen that video

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I meant to post an up close photo of the alternator pulley. My takeaway from this experience is to use a cheap stethoscope if you suspect noise coming from a pulley or accessory. Either that or a long ratchet or screwdriver stuffed in a funnel. Don't wait, don't use regular shipping if you isolate the noise to a specific pulley, especially the clutch pulley, and research creative ways to cuss when removing the alternator.

Also, every 5th Gen 4Runner owner should AT THE VERY LEAST order a clutch pulley set just to have on hand and maybe for good measure, an extra clutch pulley (I grabbed some new idler pullies too. Old ones weren't in bad shape except the slight wobble in 1, but after snapping a belt, and how long it took to get a clutch pulley in, it's worth having backups in my mind.

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According to a Gates training video (GATES TRAINING: Alternator Decoupler Pulley Inspection and Replacement - YouTube), a common symptom on high mileage vehicles is clutch bearing noise during engine shutdown (time stamp 0:30). This requires an assistant to rev up the engine to 2000-2500 RPM and turning off the engine at speed while you stand next to the engine and listen for bearing noise as the alternator rotor spins down from inertia.

A failing clutch pulley probably "binds and locks up" even when its on the verge of failure while the engine is idling, making it harder to detect noise with a stethoscope or one's ear while the engine is idling. On vehicle inspection with the serpentine belt in place requires special tools and damages the clutch pulley cover (time stamp 1:05).

Your picture in post 27 appears to show rust (or fine metal dust?) streaking outwards from under the front cover. Any streaking on the pulley or alternator housing are likely indications of a pulley about to fail and I strongly recommend performing the engine rev up-shutdown test and/or loosening the belt tensioner and inspecting the clutch pulley.

Always inspect alternator clutch pulley, tensioner and idler pulleys during a belt change. A clutch pulley should lock up in the direction of engine rotation and freewheel in the opposite direction.

This has been a good DIY repair topic. I learned a lot.

I did too. And i really appreciate the references. FYI that clutch pulley tool set I got from Amazon was exactly right. And only $28.99.

My biggest issue was just finding a pulley. The dealership charges $90 for it and ours locally still didn't have it. Found a bunch online that earliest delivery was several days.

I'm guessing like you pointed out that the failure was most likely caused by a faulty dust cap. Really surprised that a 4 yr old vehicle had an alternator pulley that rusted. But who knows.

Thank you again for the insight and help. I really do appreciate it.

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I thought you replaced the entire alternator with a rebuilt, and therefore didn't change the clutch pulley. How do you like the tool?

I'm surprised they didn't have it. That's really odd. I prefer OEM parts when I don't know the quality of after market.

I didn't intend to imply that failure was due to a faulty dust cap. I think a seal on a bearing inside the clutch pulley failed. This would have dried out the grease, overheated a bearing, and perhaps ground metal plating or special coatings into dust and then rust (or perhaps dust?) mixed with dried and well cooked grease appeared from under the cap.

Wow, looks like it went from bad to worse before you were able to finally get on top of it.
I really appreciate these threads, I know it will be helpful to folks down the road.
When you have time, it would be great if you could identify the size of the tools that fit. Looks like you can buy them separately if you don’t want to get a full kit. I did throw that $26 kit in my Amazon cart for future reference.
Gates makes replacement idlers and pulleys if anyone balks at OEM prices.

Got the OEM tool ordered and Toyota clutch pulley came in yesterday.

OP - do you think its necessary to pull the alternator off to do this job? Is there enough room to pull the pulley off with the OEM tool? Asking because I don't have the tool here yet but want to mentally prepare myself to pull the alternator if I have to.

It's been over a year since OP wrote a post on this forum. Perhaps try a private message? I'm still interested in this topic.

Welp today is your day because I have an answer!

Yes, the alternator pulley can be removed without removing the alternator. I just got everything wrapped up.

Tools you will need:
-OEM tools part no. 27261 (the amazon link OP posted has the correct sizes)
-Pulley, Alternator W/Clutch (Toyota OEM Part Number: 27415-0W131)
-19 mm open ended wrench (the longer the better)
-10mm socket/wrench

Tips:
-watch the Gates training video link in this thread! It helps to figure out how to use the tool (although its pretty straightforward)
-the 19 mm open ended wrench will turn COUNTER-CLOCK WISE as you hold the 10mm OEM tool in place.
-make sear all sockets and OEM tool fittings are properly fitted and snug before wrenching, it seems like the metal of the bearing housing is aluminum and can strip which can be a headache. I was getting close to that point of the tool slipping and not holding the pulley in place while wrenching...make sure everything is seated properly.
-disconnect the negative terminal on battery

After wrapping it up the noise is 90% eliminated. There is a faint bearing noise and I believe that is due to the drive-end-frame-bearing located inside the alternator. I've been through too many water crossings and mud pits to where my alternator is caked with mud.