Fan idler bearings?

[Miklos]

On my wifes 92 with a little over 110k, I replaced the tensioner pulley assy due bearing noise and belt squeek. About 5k miles later, I had to replace the air condiditoning clutch due to loose bearings making noise.

Now there is bearing noise coming from the fan idler. At first I thought that the water pump was behind the fan. Wrong, the water pump is what I thought was another idler pulley. It looks like the fan is on an idler pulley itself. Is that correct? Can just the bearings be replaced or do I need to get the whole assy from Cummins NW? Do I just remove the belt, unbolt the fan, unbolt the pulley then onbolt the idler assy from the front of the engine?



Thanks for the help

 

[Miklos]

Ouch! Man, they don't give anything away for these trucks. At those prices I will definately be replacing the bearing, unless of couse, my housing is cracked. Thank you kindly for the information. If I am able to cross to a non-dealer bearing, I will post the info here.



Thanks.

 

[rrausch]

Bearings are made to pretty universal specs. If you take the number on the bearing to a good bearing house they will be able to match it. 2 words of caution tho... (1) Make sure the new bearing is rated for the same speed, or a higher speed, as the old one. 2 bearings (with different numbers) will look identical but one will have higher internal tolerances and therfore have a higher speed rating. I don't know how fast our pulleys turn, but you can figure it out.

(2) When I restored my '54 Cebby 3/4 ton I put new bearings in the granny-gear 4-speed. I put it back in the truck and after about 15 miles it began to make a pretty bad whining noise... clutch bearing went bad. I pulled the trans again, took it apart, took that "bad" clutch bearing back to the parts house and indignantly demanded another. They gave me one even tho they said the bearing was good when it went out. I put it in and 15 miles later whining was back. I pulled the trans again, took the clutch bearing out and this time paid for another on one my own. 15 miles later it started whining again. I paid for a third bearing. This time when I put it in I studied it hard. It had a groove around the outside where a piston-ring fit in it, to define where the bearing would sit in the case, which in turn made sure there was no lateral thrust on the bearing. Well, the new bearings WERE an exact match to the old 1954 bearing, but the little piston-ring was a tiny bit bigger in diameter. This allowed it to sit proud on the trans. case which put a lot of thrust on it when it was bolted to the engine! (luckily I had saved the old bearings and rings and I just put the old ring on the new bearing--worked GREAT!) So bearing houses aren't God. But if you do your homework (I learned!) you should be OK.