No question here, just an anecdote about a water pump in my 86 740 sedan. Nobody at my house cares, but I thought you might get a kick out of it.

The water pump has been bad for more than a year, maybe two. It used to make a little noise, and over the last half year it has made a lot of noise. Since I knew what it was and it wasn't leaking, I didn't pay it much attention. I suppose I'm taking "if it ain't broke don't fix it" to the next level: "If it still drives it ain't broke".

It finally start to leak. It would lose about a quart of water in three weeks of my typical use. I had not actually looked at it with the engine running until last week. The water pump pulley was jumping around so much I couldn't believe the belt was staying on. I replaced the pump yesterday.

There is some 1/4 inch of play at the impellor end. The impellor has been running against and has cut into the housing. The impellor blades have wiorn down from rubbing against the housing. I presume the water pump has a pair of ball bearings on the shaft, an inner and outer. I am guessing the inner bearing has lost all the balls and is running race-on-race. The outer bearing (closest to pully) seems to be more or less okay.

This thing was beyond shot, and still it remained in service as a daily driver. Last weekend it made a 5 hour round trip at freeway speeds like this.
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-rcf

I didn't. Good call, I better do that before they clog something or eat up the new part.

I was in too much of a hurry to get it back together and going, having three kids needing to get to three separate events at three separate locations that same afternoon.

I didn't put on the new belt either, because the old one had no signs of cracking or decomposition. But now I see it had taken a set or twist from that out-of-alignment pulley. The belt runs in an arc forward, rather than straight between these pulleys.
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-rcf

"The belt runs in an arc forward, rather than straight between these pulleys."

The replacement WP's sometimes require spacers between the hub and pulley, I used 1/4" flat washers to get things to line up.

Just in case it's not belt damage?

The pulleys aren't perfectly aligned, maybe an mm or so out.
That isn't much for a v-belt system.

But the belt is not sitting evenly. That is, the flat of the belt is not straight across the pulley (looking front to back, across the belt).

I think from running on the old worn out and way out of alignment WP pulley, the sides of the belt have worn unevenly, so the front face is at a different angle to the centerline than is the rear face. I think this is throwing in a twist as it wraps the pulley and so the pully is throwing it out into space a little, and then the other pulley is pulling it back.

But if a new belt doesn't do it, then I'll try shiming the pulley.

Of source, you know what will really happen, I've proven it to you already.
I'll put a new belt in the trunk and drive this one til is breaks. :-)

-rcf
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I think what you did is pretty dumb. A water pump costs about $50 and will last 100K no sweat. Thats 50 cents per 1,000 miles.

What if your pump would have failed last weekend on your road trip? You would have been a long way from home with a ruined engine.

My grandfather was good friends with Yogi Berra. One of Yogi's favorite things to say was "be true to your teeth and they'll never be false to you." We should treat our cars the same way.
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Jonathan Knauer - 94 945Ti - fun!

Yep, you're right. I'm lucky to have gotten away with it.

It wouldn't have been quite as bad as you suggest, though.

That water pump I put on yestarday has been in the trunk of the car for that couple years. I got it when the pump was sounding just a little bad, but never got around to mounting it. I had the pump, gasket, rubber seals, plus the pair of v-belts. And tools. And two gallons of anti-freeze mixed plus one gallon of drinking water.

So at worst I expect it would have been the mighty inconvenience of changing the water pump by the side of the road.

I knew all along I was taking a chance, and was theoretically prepared to deal with it.
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OK, fair enough. It sure would have made for a memorable trip to have to do that repair roadside!
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Jonathan Knauer - 94 945Ti - fun!

Indeed. And odds are I would have been doing it in the rain, to boot.

What you said the first time is absolutely correct: It was pretty dumb to have not taken care of this long ago. Guilty as charged, I have not argument against that.

The thing I was intending to convey was my surprise at how absolutley trashed this component was yet is continued to function.
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"...Guilty as charged, I have not argument against that..."

I believe you DO have a reason for delaying maintenance. You summed it up quite well in another post:

"...having three kids needing to get to three separate events at three separate locations that same afternoon..."

Just another average day in the life of an involved dad.

Don't feel too dumb; I've done worse. I once bought an '84 240 real cheap. I've never heard a water pump so loud. Sounded like a big file on hard metal while cranking--and was almost as loud after starting. Drove it 150 miles before it left me stranded 2 miles from home. On the drive, it went through about 2 gallons of water. I stopped every hour or so to top up and let the motor cool down a bit. When the pump went, the propeller shattered the housing into tiny pieces, dumped antifreeze on the alternator, causing the warning lights to flicker and the temp gauge to sprint north. Cut her off and coasted into a parking lot. The next day, flushed out the cooling system from the top with a garden house hoping to get all of the metal bits out. Put on a new pump, fired her up, and breathed a big sigh of relief when nothing was destroyed by metal bits.

It was an '84 GL sedan, a rare combination of a stick shift, B23F, sunroof, and very nice fancy cloth seats. I couldn't say no to her, but as soon as I heard that water pump I knew there was no way I should drive it anywhere. It always amazes me how much abuse and neglect these cars (and their component parts) can take and still keep running. Over-engineering at its finest.

Jon McKeon
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'85 & '91 244s, '87 '88 & '92 245s, almost 1.5 million combined miles