H fan belt adjustment

Anyone know how to adjust the fan belt on an H? I just got one going that had a make a belt on it that broke, and after a few parts stores finally got a 3/4 by 37 inch belt ordered that is supposed to work, but I don't see any adjustment, it just goes from the water pump to the flywheel pulley. Any help is appreciated thanks,
Eric

Many additional stories in the archives. The top pulley is an adjustable shiv. the front 1/2 of it spins (when persuaded) to allow the belt to drop way down in to get it on the bottom pulley. Take out the set screw. Put good penetrating oil on the threads of the pulley 1/2, and the removed set screw hole. Wire brush the threads and apply more juice. heat the flange with a propane torch and drive the flange around with a brass punch on the setscrew boss and the boss opposite that. Back and forth back and forth, be gentle, it is possible to break it (not good). when it starts to move, go back and forth more before continuing to loosen.
When putting it back together, do not tighten it much, pushing with your thumb very hard on the middle of the belt between pulleys should result in at least 1-1/4" deflection. It is designed to be looser than any car belt. Jim

The pulley on the water pump is a split pulley, you tighten the belt by adjusting the front chive. It’s threaded onto the shaft. There is a set screw with a lock nut that goes into slots in the pulley shaft so the front half of the pulley can move forward and back by tightening or loosening it. Use lots of penetrating oil to soak the threads up, they probably haven't been moved in 50 or so years. CAUTION: The front chive will break if you tap on it too hard with a punch. A new one was still available and was about $55 two winter ago. If you break it, the radiator has to come off to replace it. The generator pulley works the same way. I have seen some welded in place, so look it over carefully before you try to adjust it. (My $0.02 worth. jal-SD)

thanks, I wondered about that, the set scrwe is gonna be the hard part the slot looks shotand yeah it's been sittingit's been 15 years since I've seen it run and who knows before that. I put in some gas cleaned the points and away it went though, just amazing, you can't let anything modern sit around that way...

Eric - If the slotted end of the set screw is buggered and you have a welder try this:

Turn the fan so the set screw is on top (12 o'clock position)

Set a 1/4 nut on top of the set screw. Now fill the center of the nut with weld.

Let it cool for a minute or two then give the nut a couple raps with a hammer.

Finally use a wrench on the nut to turn the setscrew out. The welding heat and vibration from hammer taps will free the setscrew.

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Tip: Replace the setscrew with a recessed (female) hex set screw. And apply anti-sieze to the screw threads before installing.

On my 350 Utility, a PO had replaced the original long set screw and jam nut with two short female hex head set screws, one on top of the other. That made for some real head scratching, as it was difficult to see the hole, let alone guess what might be in it. The good news was that I was able to get an allen wrench in there despite the rust/dirt. The even better news was that the wrench did manage to remove the set screw instead of destroying itself. The bad news was that I had no idea the second set screw was also in there. I was lucky I discovered it instead of breaking the pulley.

After adjusting the pulley, I took a bolt (1/4 inch, I think) and manufactured a long, slotted-head, dog-point set screw as close as I could make to the original in the parts book. I added a jam nut and so far, so good.

On my 300 Utility, that set screw was broken off down inside the casting. I'm pretty sure someone used a regular hex head bolt, which allowed them to put enough torque on it to twist it off.

The slotted head on the set screw limits the amount of torque you can apply (a good thing in this case), and having some extra threads visible can come in handy if you ever have to resort to vise grips, etc.

As Bob said, anti-seize is your friend.

Mark W. in MI