Wobbly Water Pump Pulley - Problem?

[Paul J.]

Re: Wobbly Water Pump Pulley - Problem?

Now I noticed a wobble on my 63 SB, too. Even though water pump is rebuilt. But the pulley on my car looks a bit worn out (>30years old)

Ruedi, the above advice is good. Most of the time, the wobble is caused by a warped pulley or by the mounting surface. The wobble causes an excentric rotation, which loads the bearing differently as it spins. This will eventually wear out the bearings. Sometimes the bearing just begins to fail and causes the wobble, perhaps from overtightening the belt, or a bad belt can cause it. Try indexing the pulley as John suggested. If it's the pulley this won't cure it but it can make it better.

Paul

[Cecil L.]

Re: Wobbly Water Pump Pulley - Problem?

It could also be caused by a crack in the mounting surface of the pulley. GM put out a few TSB's concerning the issue and required a reinforcement to prevent it.

[Scott H.]

[Frank D.]

Re: Wobbly Water Pump Pulley - Problem?

I rebuilt the waterpump on my 62 340 HP car about 15 years ago. It was very difficult pressing the parts off and back on the shaft but I got it done and after installation I noticed a small wobble at the pulley. Checked the pulley and it looked like the hub (flange) had the wobble.
20,000 miles later it still wobbles and does not leak.

My 63 has a wobble at idle and its never missed a beat

[Joe L.]

Re: Wobbly Water Pump Pulley - Problem?

My 63 has a wobble at idle and its never missed a beat

Frank------


This is a common problem on rebuilt waterpumps, especially those rebuilt by the inexperienced. It's caused by the waterpump hub not being exactly perpendicular to the shaft. I strongly suspect that it's the reason that GM stopped recommending field rebuild of waterpumps after 1970 and ceased supplying most waterpump SERVICE parts after about that time.

The "wobble" will eventually cause failure of the waterpump bearing and fan clutch. Of course, if one does not put too many miles on their car, as is the case for most of our antiques, the proposition of failure should not represent a huge problem. However, if I were taking such a car on long road trips, I'd be much more concerned. When I rebuild my own waterpumps (my own being the ONLY ones I rebuild), I always check runout on the face of the hub after I complete the rebuild. If it's more than a few thousandths, I start over.

[Richard M.]

Re: Wobbly Water Pump Pulley - Problem?

Joe,

Which is why when I rebuild them I use only quality kits. I check the hub runout as part of my process. Never a problem in my cases. I've had to rebuild "rebuilders" pumps due to lack of quality of workmanship, particularly from "that California" rebuilder. Both a SB and 2 BB pumps he did were terrible and all 3 had different problems. One even had a wobbly seal because he didn't even check if it was installed flat when he did it. I only found out when I had to replace the rusted out bypass nipple he left in there when he did it. I looked inside while I spun the shaft and....Geesh!

However, as far as pulley wobble is concerned, on the BB, Paragon had a poor reproduction lot years ago. Maybe they still do. They admitted to me on the phone that it's a crap shoot if it's wobble free. I couldn't believe my ears when they told me that. The last 2 I had were wobbly junk. Looked like a C5/C6 wobbly Harmonic Balancer* at idle. I ended up getting NOS GM pulleys from David Sokolowski on both occasions and were perfect.

Rich
* There were a rash of C5/C6 HB's that loose their rubber hold on the outer ring, causing a wobble and eventual damage to engine front cover if left unattended. I had one go bad on my '07. Dealer replaced under warranty. Good thing because it's a big job. Right side exhaust section and starter needs to come off to use engine rotation-hold tool at the flywheel/flexplate, steering rack must be removed to access HB bolt and free space for HB removal and installation. Unique torque requirement using new HB stretch bolt, etc, etc. IIRC it's a 3 to 4 hour job, maybe more. Must be well over $1000 or more at a dealer to replace these days. There's a aftermarket replacement that's available which is a good alternative.

If you own a C5 or C6, keep a eye on it at idle and you may be surprised.

[Joe R.]

Re: Wobbly Water Pump Pulley - Problem?

The expert Water Pump rebuilder here is Bill Mock on this forum. He has helped thousands of owners by selling or rebuilding their Water Pumps. He can be contacted thru this forum or private message.

JR

[Joe L.]

Re: Wobbly Water Pump Pulley - Problem?

Joe,

Which is why when I rebuild them I use only quality kits. I check the hub runout as part of my process. Never a problem in my cases. I've had to rebuild "rebuilders" pumps due to lack of quality of workmanship, particularly from "that California" rebuilder. Both a SB and 2 BB pumps he did were terrible and all 3 had different problems. One even had a wobbly seal because he didn't even check if it was installed flat when he did it. I only found out when I had to replace the rusted out bypass nipple he left in there when he did it. I looked inside while I spun the shaft and....Geesh!

However, as far as pulley wobble is concerned, on the BB, Paragon had a poor reproduction lot years ago. Maybe they still do. They admitted to me on the phone that it's a crap shoot if it's wobble free. I couldn't believe my ears when they told me that. The last 2 I had were wobbly junk. Looked like a C5/C6 wobbly Harmonic Balancer* at idle. I ended up getting NOS GM pulleys from David Sokolowski on both occasions and were perfect.

Rich
* There were a rash of C5/C6 HB's that loose their rubber hold on the outer ring, causing a wobble and eventual damage to engine front cover if left unattended. I had one go bad on my '07. Dealer replaced under warranty. Good thing because it's a big job. Right side exhaust section and starter needs to come off to use engine rotation-hold tool at the flywheel/flexplate, steering rack must be removed to access HB bolt and free space for HB removal and installation. Unique torque requirement using new HB stretch bolt, etc, etc. IIRC it's a 3 to 4 hour job, maybe more. Must be well over $1000 or more at a dealer to replace these days. There's a aftermarket replacement that's available which is a good alternative.

If you own a C5 or C6, keep a eye on it at idle and you may be surprised.

Rich-------


That guy in California makes a lot of the reproduction pulleys on the market probably including the ones available from Paragon. In fact, I don't know of anyone besides him that manufactures reproduction pulleys.