1973 LS4 Water pump belt and Idler Pulley Questions

[Tom K.]

Re: 1973 LS4 Water pump belt and Idler Pulley Questions

Weellllll,

It turns out the bearing for the idler pulley is on back order at Corvette Specialty with no reliable date for when they will be back in stock - sounds dis-continued to me.
However, my friend at the industrial bearing supply place came up with a decent option. NSK P/N 885586. The shaft of this bearing has to be cut down on both ends, but the body of the bearing is the same and the shaft diameter is the same. The NSK bearing is actually a water pump bearing and is sealed rather than shielded.

I will continue to research the proper bearing and post any updates.


Tom Krause

[Bob W.]

Re: 1973 LS4 Water pump belt and Idler Pulley Questions

Tom, Any updates on your pulley rebuild ? Yesterday I received a new c1 catalog from Zip Corvette and it shows a replacement bearing m-4273 for $84.99.

[Tom R.]

Re: 1973 LS4 Water pump belt and Idler Pulley Questions

I caught the initial date of this discussion and plowing through the technical, the thought came...this is worthy of a Restorer technical article...given the final assembly!

[Tom K.]

Re: 1973 LS4 Water pump belt and Idler Pulley Questions

Tom, Any updates on your pulley rebuild ? Yesterday I received a new c1 catalog from Zip Corvette and it shows a replacement bearing m-4273 for $84.99.

Hello Bob,

It has been a while since I looked at this post. I checked Zip Corvette at the time I tried this and the bearing was not in stock. I checked this evening (Aug 2022) and still not available. I got really busy at work when I originally posted about this, so I bought the replacement assembly with the gold idler pulley just to get the car on the road. Then I never got back to completing the repair of the original idler. I think it's about time I do that...

[Bob W.]

Re: 1973 LS4 Water pump belt and Idler Pulley Questions

Tom Did Zip say when they will have the bearing? Todd Larson used a Zip bearing, Check thread 63 FI Idler Pulley by Todd Larson started December 27 2021.

Good Luck let us know how you make out Bob

[Joe L.]

Re: 1973 LS4 Water pump belt and Idler Pulley Questions

Weellllll,

It turns out the bearing for the idler pulley is on back order at Corvette Specialty with no reliable date for when they will be back in stock - sounds dis-continued to me.
However, my friend at the industrial bearing supply place came up with a decent option. NSK P/N 885586. The shaft of this bearing has to be cut down on both ends, but the body of the bearing is the same and the shaft diameter is the same. The NSK bearing is actually a water pump bearing and is sealed rather than shielded.

I will continue to research the proper bearing and post any updates.


Tom Krause

Tom------

I don't like the idea of turning down the ends of the shaft. I believe these shafts are case hardened which means the shafts are only surface hardened. So, when the shaft is turned down the hardening is lost.