Replacement water pump

I recently pulled the water pump off my 389 to replace it, since it was leaking, and found that the replacement didnt line up quite right with the stud mounts. I discovered the difference being two of the holes on the original one are off center of the tab they are drilled in. The replacement is not off center, thus will not go on. The original casting number is 518040. Searching this number I found one on ebay that looks the same as the replacement I returned, and the description for it says '61-63 Pontiac Tempest 4 cylinder application. Is it possible that someone has already replaced this water pump with the incorrect part number? Does anyone know the correct replacement part number for this? It is a four hole, cast iron impeller, and I believe it spins clockwise. If someone can explain to me how to upload an image, I could show you what it looks like. ty.

wydtrac......I couldn't find the number you had in any of my parts manuals. That could be an old number that was superseded. The 60 manual lists 540069 for all 1955-1960. The '72 manual lists 540069 for all V-8's 1955-1962 and some 1963's. The Tempest 4 is part number 540071. The number cast on a part doesn't always correspond with the actual part you are looking for. For example the number you have could be for the cast housing, not a complete water pump assembly which is made from 6 or 7 parts. Hope this helps.....John

It does help and I will search on the part number you supplied.
Thanks a lot Catbird!

Try rotating it. I think the holes are slightly off and it only fits on one way. That's what I noticed on mine when I installed it.

But if you have the wrong one and it fits, but the right one does not fit maybe you need to look into the whole timing cover assembly being wrong.

This will be interesting to find out what the problem is.

Try doing this to post pictures.

Ok, the best way I can figure out is to click on the "host an image" icon (the one with the picture with a disc in front of it), find the picture you want to post in the thread, then "host", then select the bottom link, copy it (the copy button is not working for me), then click on the host an image icon again to close it, the click on the "image" icon and paste your copied link in there. That works but that is a hassle. I don't know why it sucks so bad.

Either that or upload your photos to a host like photobucket or flickr or something like that and you'll see an IMG link. Copy that and paste it here. My friend has my copy of dreamwaver but once I get it back I'll reinstall it and upload a gallery for us. It will be much better than this image hosting crap.

starchief_59 wrote:

Try rotating it. I think the holes are slightly off and it only fits on one way. That's what I noticed on mine when I installed it.

But if you have the wrong one and it fits, but the right one does not fit maybe you need to look into the whole timing cover assembly being wrong.

That's actually what was going through my head reading the first post.....

Well, I did try rotating it, not having paid attention to the details of the original pump. There is one tab that has a straight angle to it rather than being rounded like the rest. That seemed to line up with a similar angle on the housing at the top. When it didnt fit on that way, I tried rotating it to no avail. Did I rotate it all the way around to all the different holes? I cant for sure. Maybe not. I just know I tried everything I could think of because I couldnt believe it would not fit on. I returned it to NAPA and they took it back. I did find out last night that the original number is 540069 as Catbird said, but also that the NAPA number is 58594 which is what I had that wouldnt fit on. The guy at NAPA says we should order another one and see what we get. He thinks maybe the wrong one got put in the box we got. What is confusing me is that the original one has two of the holes offset from the center of the tab it is drilled in and non of the replacement ones I have seen are that way. I will get another one from NAPA and try it on before I put 7 coats of Pontiac blue paint on it. [img][/img]
Hey! It worked, the image is there. I think you can see the two bottom holes are slightly off center of the tabs.

wydtrac.....I checked out the one on my car and the rebuilt one I have as a spare. Neither of them had the mounting holes off center on the tabs, at least to the naked eye. Is that what is keeping it from mounting? You might want to elongate the holes if that is the case, or as you said, try another one from NAPA. I got my spare from Ames a couple years ago, but checked the fit right after I got it. Kanter is also a good source for engine parts if you can't get one elseware. Hope this helps.....John

I had NAPA order another one just to see if it would be any different. I got it today and we measured the distances between the holes on the new one compared to the old one. They look to be identical. The first replacement we measured and the holes were not the same. (this is how my life goes!) I will try this new one on the car BEFORE I paint it and try to mount it. See, I can still learn new things. Thanks for the help John.

Make sure you try to rotate it before you give up. I think mine only went on one way.

Let me go through my pictures and see if I have one where you can see the waterpump.

Ok here are some pics I found before I got my motor rebuilt. Notice the orientation of the flat spots on the tabs. That might matter. And I can't read the numbers but note where they are and try to line yours up like that

Thanks for the pictures. That helps confirm the orientation of the flat spot on the pump and where it goes.
I found that the second new one from NAPA does indeed fit if put as your pictures show. But I swear that I tried the first one that way and could not get it to go on.
Well, it does not matter now anyway. I am painting this new one and expect it will be fine. I kept the original one just in case. I may send it to be rebuilt and save it as a spare.
My replacement oil pan is in the mail and on the way from AZ! The pictures look great. I am anchious to get it back together.
Thanks again as always for all the help.

Sweet! Glad to hear it. Keep us updated.

I got and installed my second replacement water pump. Using your pictures I lined it up and it slipped right into place. (I tried it before I painted this time!)
Thanks again for the pictures.

glad I could help