The Stovebolt Site Forums The Shop Area Engine Shop Bizarre water pump pulley failure.

So, my '49 panel, has a '56 235 in it. I didn't put it in there, it came that way from the junk yard.

This fall, my water pump started to leak an enormous amount, so I bought a reman 235 pump, and stuck the 216 pulley onto the "new" pump and cut the extra shaft off.

Today, just as I pulled off the highway, I heard a terrible racket up front, and pulled over.

Much to my chagrin, I found that the hub had parted ways with the pulley. No radiator damage, which makes me pretty happy!

Now I'm curious, has this happened to any of you-all?

It looks coppery-ish in the break, so I assume that the two pieces were brazed together, was this done at the factory, or has this been repaired before?

Here are a few pictures:


http://i221.photobucket.com/albums/dd45/HomeCrafter/IMGP2490_zps293daeaf.jpg


http://i221.photobucket.com/albums/dd45/HomeCrafter/IMGP2486_zps3df239e4.jpg

I'm sure someone can chime in, however I would expect the pump might have been spinning faster then needed.... OR, is it possible that the fan was not balanced well and the vibration caused the hub to crack?

I am not able to look at your pics because of the computer I am using...

belt too tight? pulleys not perfectly aligned?
doubt that was brazed, too clean a separation, probably a press fit that fatigued from mechanical or thermal stress - what's with the hammered looking end on the shaft?

Bill

The shaft wasn't hammered, I didn't have a zip-disk when I cut it off, so used a regular angle grinder wheel, and came in from the sides, so I didn't heat the shaft up too much. And then didn't grind it flush and pretty!

The pulleys weren't perfectly aligned..... But really close.

The belt wasn't tight, worry about wrecking bearings.

Looks like a cheep aftermarket pulley. GM pulleys are not made like that and would not come apart.

Just wondering, are you running a 235 pump in the stock location? Or is yours set up to run the 216 pump with the adapter? I ask because the 216 pulley on a 235 pump will overdrive the pump. It could also possibly be the cause of the pulley failure, possibly combined with both of the suggestions that red58 made.

I'm running a 235 pump, in the stock location, which I know isn't ideal, but that's how it goes for now.

You're right Dave, the pulley doesn't say GM on it, like on the other knackered pump I've got.

So the 235 pulley is larger diameter than the 216 pulley?

The correct pulley for a 1955-62 235 is about 7" in diameter.
The most common problem running your setup is thrown fans. Running at the faster speeds the fan flexes more than designed for and will crack and break.

Yes, the later 235 requires a larger pulley.

Oh. Thrown fan doesn't sound fun!

I guess it's good I don't drive over 45 mph!

Thanks for the insight.

Christopher,
I think you are right, the reddish area is characteristic of a joint made by the furnace braze process which is used in many controlled production operations.
I think you had to drift the hub deeper onto the shaft and if force to move it was applied to the fan mounting flange instead of the hub it could have started the failure of the brazed joint.
I probably wouldn't have noticed the two piece pulley/hub and done the same thing because the hub is so narrow.

Just so I understand the pulley differences, is the 235 damper pulley larger than the 216 pulley?

Actually, the water pump pulley that came apart, was a slip fit onto the shaft, its held in place by JB Weld!

The balancer pulley used to run the high mount 216 style pump is 6" in diameter, this was used up through 1954.
1955-62 balancer pulleys are 6 3/4" in diameter.

I am glad you posted this fact. My pulley is about 4 1/4" diameter and I am convinced it is too fast, fan makes a lot of noise. (Engine is 1960 261) Thanks.

Had a pulley do the same thing. Pump had been leaking, after the pulley failed the water pump was bound up. Could barely get it to turn. This was on a 235 in a 54. my guess was the pump failing may have caused more strain on pulley.