Fan Belt Idler pulley replacement

[lemondana]

I was going to post this on here awhile back but I got it on FBBO instead. Well anyway: I have a cheaper alternative to replacing this fan idler pulley. The repro's are pretty high. Most of the AC cars used these till 1972 I think. Check yours out-it might be rougher than you think, needing replacement. Continental which replaces Goodyear has a nice pulley. But you will have to remove the shoulder from your old one to use in the new one. As one member over on FBBO suggested, have the dust cover cut off by a machinist and you could probably use it on the new one-tack it in place. These are not common shoulder bolts, I have not been able to find them anywhere. The Continental number is 49034, they are only like 12.00 dollars on Rockauto. I have pictures if I can get them loaded on here.

 

[lemondana]

These are for the narrow 13 series belt. I'm sure most of us have an extra pulley and bracket in our parts stash. Disassemble one, get the new pulley with the bolt you took out of another one. That way you don't have to take the bracket off of the motor and dribble anti-freeze all over.

 

[patinated_imperial]

Great tip! I did something similar last week and thought I was a first mover.
I think Continental 49034 is for 0.5" wide belt?
In any case, I had ordered the replacement for the original part no. for my imperial from rock auto (FOUR SEASONS 45954).
My '66 originally has the narrower belt 0.375" for the fan and water pump pulleys, which made it necessary to reduce the diameter of the shoulder bolt.
It looks like we wen't through the same trials. I.e. first tried to drill out the spot welds of the cover, but then changed strategy to cutting it off to be able to reuse the bolt.
When I got mine off, I found the original bearing was 0.67" ID (same as yours for the 1/2" belt pulley) and the new pulley had a bearing with 0.47" ID.
So I turned my bolt down to 0.47" (11,66mm). If anyone ever wants to use one of the original reproductions on this car, a new shoulder bolt comes with the pulley - so no harm done.
(it was not an option for me just to get a new bearing for the old pulley - it was very loose on the bearing OD as well.)

 

[Big_John]

If you use this pulley with the inner groove (closest to the engine) and loop the belt around the crank, P/S and water pump pulleys, you can toss the idler pulley and only need one belt for the P/S and water pump. This is the way my '70 is now set up.

BPE Water Pump Pulley - Bouchillon Performance Engineering

 

[patinated_imperial]

THanks Big_John.

Do you remember what length belt you ordered?

 

[Big_John]

THanks Big_John.

Do you remember what length belt you ordered?

I used a NAPA 25-7465 which is a 46 1/2" Gates belt. I keep an old belt that I have cut just for these occasions when I have to figure out a belt length. Just wrap it around the pulleys and mark and measure. It gets you very close to what you need.

When I change belts, the old ones always go in the trunk and since this car got a non-standard belt, I took a pic of the belt sleeves and store it in my phone to make things if needed easier out on the road.

And just to show how the belt is routed.