Belt info on my M1123 with 6.5l serial number below 196901 (edit: and idler pulley bearing number)

[Coug]

So just putting this information out there in case anyone else needs it.

My truck is an M1123 with the 6.5 engine and serpentine belt setup. It has the Sanden compressor for the RedDot aircon in it. That part is probably important, as the belt length does not match what the manual says it should be.

Serial number is below 196901 so it falls into the earlier category. The manual says it should be a 98" serpentine belt. This is not the case for my truck, so I figured I would share.

The belt that was installed on my truck was part number K081102. 1 3/32" x 110 3/4" or metric 28mm x 2814mm


(the manual gives an NSN of 3030014669476 for the 98" belt, which has a bunch of manufacturer part numbers found here: https://www.parttarget.com/3030-01-...-1.html/-EC7998AC-A023-4088-9599-08896F604ABB )


Second thing I wanted to share was my tensioner experience. I had a belt issue, ordered a tensioner as part of my troubleshooting. It worked just fine until I solved the real issue, which had to do with a loose PS/Generator bracket, which was throwing off alignment and making the belt a little looser than it was supposed to be.

Anyway, the belt tensioner I installed was Dayco 89478.
It physically fits the same location, no issues with it until the extra slack was taken out of the serpentine belt. At this point it started contacting the belt.
The part rubbing is the tension limiter tab (or whatever it's called, the little tab that keeps you from putting too much tension on it/turning it too far)


Basically, the part rubbing is non essential for the tensioner operation, so I plan to just grind it down later on so it doesn't contact the belt.
AM General wants over $300 for the original one, the one I listed above I picked up new for under $100 on ebay, and if you don't mind cheap chinesium parts other cross references of the same part number as the Dayco can be found less than $40 as it's application involves things like industrial equipment and buses. MUCH more common than the original one.



Anyway, just posted this to put the information I found out there in hopes that it helps someone else out later.

 

[Coug]

On slightly related note, I had the idler pulley on my belt tensioner fail today while driving. (after reading previous post where I talk about a replacement tensioner, I ended up selling the one pictured above to another member on here and last I heard it was doing fine, so this post is about the original tensioner that came with my truck)

This makes the second idler to have failed bearings.

This time, due to how hot the pulley got and the belt, I managed to snap the serpentine belt. Luckily I keep one tossed behind the driver's seat.

On the plus side, the pulley has replaceable bearings.

2 bearings per idler pulley
Bearing number 6203

Once the failed bearing cools off enough to safely remove from the vehicle, all it takes it a small flathead screwdriver (or other thin tool that can be used for prying) to remove the snap ring that holds the bearings in.
In my case the old bearing pressed right out. New ones had to be driven in. I used a rubber mallet and one of the old bearings outer race to drive the new ones in. Wasn't that difficult, but took a few hits to do so without risking damage.

As far as I know, this is the same bearing number for all 3 of the idler pulleys.


I do want to say thanks to my local NAPA for not only having the bearings on the shelf, but also providing the tools to remove the pulley (T50 bit for the tensioner pulley) and paper towels to clean up while doing the disassembly/reassembly on their counter.

Hoping this thread helps anyone looking for either the belt or the bearing part numbers.

(going downhill on icy logging roads is a terrible time to find out that you have failed bearings. Fortunately I wasn't alone out there, and the guy out with me that I had only just met had the wrench needed to remove the tensioner, and drove me to the nearest auto parts store.)