tightening fan belt on caterpillar 12 grader

I’ve heated the adjuster and drenched it well with loose juice; you could “gingerly” use an air hammer on very low pressure setting and a suitable shank. It’s possible your pulley is worn and you could be out of adjustment also. Be careful and good luck. JM

Hey JM thanks for the response. I will give it a try. I did a little more looking back on here and found a few other posts to about this on a D6 9U and I didn't think about it but they have the same method of adjustment, duh on my part. Ill see what I can do and report back. Thanks again sir.

The older ones have webs or ribs cast into the rear of the adjustable pulley. These are perfect to jam a short rod, deep socket or short extension between a web and bolt heads etc on the water pump to hold that half of the sheave stationary while pushing or pulling the fan blade to turn the front half.

I have also heated the rear flange when I couldn't move it any other way. Doesn't do the belt any good, but frequently it's time to get a new one to have on hand when you have to tighten the old one a lot. Tightening a new belt is par for the course, just something to be expected, but tightening an old one is frequently the first step to replacing it!

The new designs are made for a pin spanner to engage in the holes where the locking tab bolts are removed. There's not much else on the back side of those. I have seen them which were adjusted using a cold chisel!

The correct tool for adjusting the pulley is an adjustable pin spanner wrench that fits the recessed holes once the locking tabs and bolts are removed.

Thanks for all of the replies guys I really appreciate it. In about an hours time from when I first posted I finally got the pulley to come free with a little PB and Wd. Then with a piece of round stock from the shop, a short 2 x 4 and a small ball peen I lightly spun the pulley and got her adjusted to recommended tension. I think the threads just had enough rust and grime in them that it was just needing oil and worked back and forth. I will be keeping this thing in operating order from now on so I don't have to deal with that nightmare again lol. But thanks again for the help I would be pretty lost without all the help all the time.

Glad you got it working. One thing I will add is when I did my 112 once I got it moving I took the fan belt off and spun the hub back and forth until I could spin it by hand. Then I cleaned the threads and painted them with antisieze. Keeps everything nice and you don't have to fight it next time