Grand AM water pump, Help!

I have a 94 Grand Am with the 2.3 liter engine Single Overhead CAM (vin 3, I think). I have just got over 200k miles. I think the car
sensed I was starting to lock at newer cars. Well the water pump just went out.
I am in the process of replacing the pump. I have everthing off. The exhaust manifold, pump housing and pump. Now the problem. I go to mount the new pump to the timing chain housing and it won't go. It mates up with the splines ( I had to rotate it slightly) and then it bottums out. It needs to go in about 1/8inch farther. I have measured the pump for the distance from the pump housing mounting flang to the end of the splined shaft. It is about 0.925 inches. I did a depth measurement on the female end if the idler. It is about 0.817 inches deep. The difference is about an eight of an inch. I have got another pump from NAPA this time, thinking it is the wrong pump. The pump depth dimension is pretty close to the first pump.
I have looked inside the housing at the idler. I don't see anything damaged or out of place. The snap rign is still in place. and the idler bearing looks ok.
Important note: I checked the old pump and found that the distance from the shaft end to the mountin face is about 1/8 shorter than the new pump. However I can push up on the pump impellers and make up for this difference (about 1/8"). The pump tends to spring back. Push up 1/8".
I can only think of two things that may be the cause. 1. The pump is still not the right one for the car. The pump may be different for this particular VIN. In which case I may have to go to the dealer and check out a pump from them.
2. The idler and bearing have moved out of the housing seat by 1/8 of an inch. If this is the case how will I reseat the bearing. The book says I have to take the housing off and take it to get the bearing pressed in to replace it. I hope i don't have to take the timing chain housing off. If this is the problem then this may have been or contributed to the demise of the pump.
Experience... Comments...ideas, please. The help is appreciated.
Thanks Kevin
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"Kevin" wrote

If you are fooling around with aftermarket pumps...I'd suggest that you stop right now and go get a GM pump. Perhaps the aftermarket ones weren't assembled right. Just bite the bullet and get a new pump from GM and then you shouldn't have to worry about stuff like this.
Note: make sure that you draw the water pump housing up to the block and water pump in small increments. You want to make sure that you do not warp the housing or put undue stress on it or the water pump. Do you understand what I'm saying here....because you have two bolts going into the block and 5 bolts going into the water pump itself and there is a 90 degree difference between the two sets of bolts...you can't just tighten one set up first without making sure the other set of bolts are very close to being tight themselves.
Ian
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I stoped by a dealer and looked at there pump and it looks like it has the same dimension as the two after market ones I have. I don't think it is the pump at this point.
I think I see what is going on. The idler shaft has a spring loaded end on the base of the female end (with the splines that mate to the pump). I took a screw driver and was able to push on inside of the idler to feel the spring. It seems to be a pretty stiff spring. I will have to put the pump in place as before and then push the pump on to get the nuts started. This was supprising since my haynes manual does not mention this.
I stoped by a dealer and looked at there pump and it looks like it has the same dimension as the two after market ones I have. I don't think it is the pump at this point.
Yes I understand your comment about the two mating surfaces. I will leave the bolts somewhat loose/snug until I can thighten all about the same time.
comments?
Kevin

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you have lost me there, any after market pump should bolt right on with ease. you dont have to remove the timing cover. take te original pump to the store and tell them they gave you the wrong pump. maybe he can spot the diference. i have changed over a hundred of these pumps with no problem. grind on it, file on it but dont hammer on it.
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I stoped by a dealer and looked at there pump and it looks like it has the same dimension as the two after market ones I have. I don't think it is the pump at this point. I have looked at three pumps now and they all look the same the shaft sticks out above the pump body by the same dimension.
Looking at the old pump, I can push in on the impellers about 1/8" and watch the splined shaft go up about an 1/8", to where it would match the new pumps. The water pump shaft also seems to be spring loaded as I can push on it and it spring back. Also the bearing in the old pump has the seal pulled out of the inner race. If the pump bearing wore out and the idler spring pushed on the shaft, the inner race seal would pull out of the inner race. I may try to take the old pump apart to look at the bearing.
It seems that as the pump was failing, the spring in the idler pushed the pump shaft out. The pump impeller started to scrap the water pump housing (the housing that bolts to the water pump the outlet pipe and the block). The scrap marks are obvious.
When I put the pump on previously, I rotated the pump shaft to align the splines. The pump would go on farther, but it would button out about 1/8" away from bolting cleanly to the timing chain cover. The mating end of the splined pump shaft looks exactly like the photo in my haynes manual. In the female splined end in the idler appears to be disc with a hole in it. I can push on it with a screw driver and feel a spring in it.
I think I just have to put the pump back on and push the pump on to compress the spring to get the nuts started on the studs. My concern is that the haynes manual does not mention this.
Whe you replaced these pump have you had to compress the spring to mount the pump? BTW I have a vin number 3 grand am SOHC 2.3l
Thanks Kevin
snipped-for-privacy@webtv.net (GREASY DICK) wrote in message

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wrong pump, try put the old one back on
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