Belt rubs water pump '73 Eldo

[McNade]

Well, I have been driving my '73 Eldorado just as she came to me, with one belt instead of two driving the power steering pump and the a/c.  While changing out the water pump I ordered the AC Delco (made in china) water pump made for the two belt system assuming that the wrong pump had been previously installed.  Nope, that inner belt still rubs on the water pump as if the bottom crank shaft pulley is in too close to the block.  My book shows all the parts seem to be in order.  And the pulleys all seem to line up okay, it is just that the water pump is about 1/4 inch in the way and the belt rubs on the pump.  Any suggestions other than taking a grinder to the pump? Thanks in advance for any help. Mcnade   

[TJ Hopland]

Knowing you already tried a different pump I think if it was me the grinder would be coming out unless this is a show car.

I don't think there was ever different spacing on the rear grooves, difference was single vs dual and smog or no smog which only effected the front groove.   Limo CC with the HD alternator had an additional groove pulley that nested in the standard one so that would not effect the rear groove either. 

I have never seen a different pump in person, only in a photo one time I think.   There are subtle differences in the pumps but I have never seen a difference in the area in question other than one photo.   I don't remember which site the photo was posted on.  It was a guy that I think did this era Cad salvage on the side that had a lot to choose from.

[McNade]

Thanks TJ.  Nice surviver/driver, but not a show car.  And grinder work would be in a place hard to notice.  So it may be the grinder.  It all worked well with one belt, but every time I open the hood I see that empty pulley groove...  unless someone else has a better idea I may just get out the grinder.   

[fishnjim]

Shows a first and second design pump for 2 belt this year, so U need to check that the original motor, etc. numbers and check the build date and double check the parts numbers.   
I'd also check with a straight edge that the pulleys are in line.   1/4" may not be obvious.  If in to far, then need to repress the fan stop to the correct dimension.   Probably not the crank pulley, that one shouldn't adjust.
I had a similar issue after rebuild and it turned out the water pump pulley was off, but had been correct before the rebuild.  Had to move it a tad.

[35-709]

There were/are 2 different water pumps, one for the 2 belt system and one for the single belt system.  Very hard to eyeball the difference but it is there.  Been there done that!  If you order a new water pump for your 2 belt system you will get one for the single belt system.  That's just the way it is these days.  Either pump will fit just fine, but the single belt pump will rub when used with the 2 belt system, period, end of lesson.  The ONLY way I know of to get the correct pump for the 2 belt system is to get a rebuilt pump specifically for your 2 belt setup.  You cannot get a new one for the 2 belt no matter what they say at the parts store or on RockAuto, etc.  After 2 new pumps (both supposed to fit my '73 2 belt system) my counter man and I finally saw the difference in their new pump and my old pump and they ordered me a rebuilt instead, end of problem.  I kept an old 2 belt system pump for rebuild and put it on the shelf for "next time".

[Bob Hoffmann CLC#96]

Geoff,
Thanks for clarifying that point again!!
Bob

[McNade]

Thanks - I was beginning to think either I was crazy or something was very wrong with my car.  I have another supposedly two belt pump on order from Autozone, figuring Rock Auto sent the wrong one.  This next one is a different manufacturer.  If they get it right somehow, great, but after your information now my expectations are low.  I will begin to locate a rebuilt pump. Thanks for saving my sanity.

[35-709]

Geoff,
Thanks for clarifying that point again!!
Bob

  Sometimes I just can't help myself, Bob!

Thanks - I was beginning to think either I was crazy or something was very wrong with my car.  I have another supposedly two belt pump on order from Autozone, figuring Rock Auto sent the wrong one.  This next one is a different manufacturer.  If they get it right somehow, great, but after your information now my expectations are low.  I will begin to locate a rebuilt pump. Thanks for saving my sanity.

Please let us know how you make out.  I am sure everyone with a 2 belt system, including myself, would like to know if the early style is again available new.  I got my rebuilt pump at Carquest but any good parts store (NAPA) should be able to get you one.
Actually, my brother-in-law owns my '73 now but I know who will be doing his work if needed.   

[McNade]

I opened the Auto Zone two belt water pump from Duralast in the store.  Wrong one as predicted so did not accept it.  I saw a rebuilt one on Parts Geek and the photo shows a definite difference where the belt passes by the pump vs the single belt pump.  Soooo,  that is ordered and we'll see what washes in over the transom.  Rock Auto's AC Delco pump is heading back too.  Will keep you informed as the saga progresses.  My original pump worked fine, just on one belt.  Decided if grinding ultimately is necessary I will grind on the old one with the nice blue paint on it.  But we'll see what the Geeks have for me. mcnade 

[McNade]

Thanks everyone.  Received a rebuilt water pump as suggested.  It has a deeper groove where the belt passes by.  All the new pumps are too thick in this area and the belt will rub which is what my car had when I bought it.  Another way to tell the difference between the single belt pump and the double belt pump seems to be the impeller.  On the single belt pump it is round and enclosed while on the older double belt pump the blades are exposed.  It I can figure out how to post photos here I will do so.  Thanks again for the help!

[McNade]

Here are attachments that I hope are posted as photos.  If not, help!

[35-709]

Very good!  Glad you got it taken care of. 

[cadillacmike68]

Next time try a FlowKooler pump, a much better impeller and once you paint it Cadillac dark blue, it's difficult to tell it's not OEM, and it might be anyway, at least the cast iron part.

https://www.flowkoolerwaterpumps.com/products/1778-1968-1973-cadillac-500-and-472-with-double-groove-pulley-water-pump