Idler Pulley Flange Nut

The bolt itself can be drilled, tapped, and replaced with a stud, if necessary.

 

2005 Toyota Prius Parts - Frank Toyota, Scion & Hyundai

 

Hi Dean,

I can visualize how the nut was damaged by use of a 12-point socket which slipped. However I am wondering what caused the damage to the bolt threads?

 

Hi Patrick. He said he had to destroy the nut with a cold chisel, so that would definitely damage the bolt and threads too.

 

Think about it like this. A 12 point socket only grips the hex head on the corners of the hex whereas a 6 point socket grips not only the corners but the flat area of the hex head also. Using a 6 point socket is advisable any time you are dealing with a tight bolt or nut.

It is very possible that the guy before you put some lock tite on the nut. Not necessary, but who knows what or why.

Stick with Craftsman tools and you will do okay. Sears brand wrenches and sockets are not "Craftsman" quality. Make sure they say "Craftsman" on them.

Like Mike, I am a former machinist too. Many ways to make that bolt. Easier to buy one though ready made than it is to set up a machine just to make one part. If you worked in a machine shop and had access to the tooling and the machinery it is not a problem. But to pay someone to make one would not be cheap.

Best of luck to you!

 

Rude person's and Dorunron: Thanks for your advice and offers of help. In the future when replacement parts might not be as easily available, I think it will be good to have people like you to advise on alternatives. I'm not sure of the size of the thread in the bolt head (the tensioner bolt that screws into it has a 12mm head), but I can measure the diameter of the hole if you like.

Patrick Wong: Thanks also for pointing out the importance of what kind of socket is used. I think I will be investing in a 6 point socket set. Yes, as uart says, I damaged the bolt thread with cold chisels. The nut lies in an indentation and is hard to get at.

I hope no-one else ever has to do this, but if using cold chisels: instead of destroying the nut, it might be worth trying to dig the chisel into the flange of the nut at a place such that the force of the hammer strike tends to turn the nut counter-clockwise. This might loosen it. The nut might have to be replaced but that is much easier than having to replace the bolt. Placing a small mirror underneath the idler pulley and wearing a head torch helped to illuminate the nut.

ps. there was no evidence of any rust on the nut or bolt - so I don't think it was rust that made it hard to
loosen.

cheers,
Dean

 

If the bolt head is 12mm across the flats, the threads would likely be M8x1.25 according to the J.I.S. standard.

 

I am in the middle of chiseling mine off (2001) 4 hours to do a 15 minute job. Had to get away for a bit. It won't move!
It is like it is welded. I'll need both the nut and bolt. .. Back at it..

 

I have drilled through the nut and bolt bashed and beat and heated it. It won't move. I guess the edge against the pulley is still holding on.

 

Once you damage the nut and bolt, it will be very hard to remove. You should've just used a big pipe to give you a little more leverage, that always does the trick.

 

I have messed mine up too! As long as I am going to replace the entire pulley unit what are your thoughts on using a saws all to just cut the darn thing off rather than do the chisel technique?

 

If you are going to have to destroy it to remove it why miss heaven by an inch, cut away. Saw, dremel with cut off wheel, die grinder, right angle grinder whatever you operate in the space.

With all the reported difficulties in removing this fastener, I wonder if it is pinch fitted from the factory in leau of a thread locker much in the same manner as suspension fasteners. Those can be chore to remove as well.

 

I personally do not understand the difficulty experienced by some owners in removing this nut. If you use the correct 6-point socket, a 3/8" cheater bar, and an extension (I use a short length of steel pipe over the cheater bar) to improve your leverage there should be no problem.

 

Patrick,
I tried the cheater bar with the correct socket and ....well nope! Maybe its the high mileage and its just not going to budge....only 410,000 miles. I did not try to heat it, but it will be off this weekend as the new part is due in today.

 

you need to get a LONG pipe to use as a cheater bar. Give yourself a little more leverage

 

Yeah that nut was definitely a *lot* harder to loosen than I was expecting, especially considering the fairly modest torque specs for that fastener.

I started with a long pattern double box end wrench (ring spanner) and soon realised I'd need more. Came back at it with a nice strong 1/2" drive hex socket and breaker bar, and realised I'd still need more. The picture below is what I finally ended up using to shift it.

 

well that one I used was a bit shorter, but that long attachment will definitely do the trick.

 

Try a length of steel pipe to extend the cheater bar length. At 410K miles I am surprised this was not previously loosened to replace the serpentine drive belt, at minimum - and perhaps also to replace the engine coolant pump two or three times.

 

I believe that my coolant pump has been replaced twice now and the coolant is due to be changed. Has anyone had to change motor mounts? The pulley will be done this weekend....

 

Hi !

I have exactly the same problem on a 2008 with 88000 km (55000 miles). I'll try to do as uart, we'll see. I hope I'm not going to break anything!