Ben Taylor

I've had to return 4 water pumps from 3 different stores for my 81 because they all cracked right at the spot that the heater hose fitting screws into the water pump, it looks like the A/C bracket is putting pressure on the fitting causing it to push against the inside of the water pump and slowly create a crack. Has anyone used new water pump on a 81 for a year without it cracking?

Chris Fowler

I'm about to put a new water pump on an '80. I'll be an AC Delco. I'll let you know next January if it cracks or not. ;)

I sure hope it doesn't...

Paul L

I have never seen what you have described. This is a re-built #330813 AC Delco pump (used 1978-82) that I hold in reserve in the basement for a possible motor re-build. I do not understand the relation between an A/C bracket and that hose outlet???

Ben Taylor

I meant the smog pump bracket, it goes over that metal pipe on the passenger side of the car, the pipe you have in your pump wouldn't even let me put the bracket on the pump. Mine has the six sided part out farther.
Is there supposed to be anything between the pump and the smog bracket? Maybe I'm just missing a spacer.

Paul L

I do not have A/C on my 1979 but here is the set-up with the original 22-year-old water pump in place. I really do not know what your problem is....? Wish I could be of more assistance.




[Modified by paul79, 11:23 PM 1/3/2002]

Ben Taylor

I don't have a camera or anything so I made this picture in paint, I can't draw to good, but I hope you can still tell what everything is, the pump is blue, the bracket is red and the little piece of pipe is the white circle, the more I look at this the more I think I probably lost a spacer or something when the original water pump busted last year.

Paul L

Sorry, Ben. I hope someone with A/C can help you.

jeffnles1

The AC bracket on my 76 doesn't look anything like that. It comes down to kind of a "Y" around the the heater hose. There's no bar going over the hose outlet.

It may be an "improvement" GM made between 76 and 79. Because on the 76, it's a bear to take the water pump off. YOu have to remove the bracket from the compressor. You can't just take the 2 bolts off and rotate the compressor out of the way.

Jeff

redc3vette1

i just replaced mine about 2 months ago so if it happens ill let ya know but so far so good GOOD LUCK :cheers: :cheers:

Carl in LA

I can tell you about another spot that splits easily on the cast water pumps... I tightend the heater hose outlet too tight into the body of the pump and guess what gave... yup, nice little split running down the side of the opening... This was on a Stewart high flow. I figured that the Stewart was nothing but a core rebuilt with a different impeller and sure enough... just about the same thickness of metal as compared to stock. I suspect someone overtightend a bolt... gotta use the torque wrench...

Larry B.

I have been around corvettes for many years and never seen a cracked water pump. I do not use rebuilt stuff though. You get castings that have been "Bubba Tested" many times and could have been marginal when you get them. :chevy

john's '81 mouse

Ben, I don't have an assembly manual (AIM) for an '81, but I know other forum members do, like Dallanex, and am sure the manual would show whether a spacer is involved in mounting this smog pump bracket. I removed the smog pump on my '81 nearly 4 years ago (it was frozen, with no belt, when I bought the vette), and can't remember how the set up was installed, but I've got the parts in my garage attic at home and could take a look tonight, and see what all is there, if you don't hear from a forum member with an AIM.

The Dude

Try not torquing the heater hose fitting to darn tight.

Pipe threads (NPT) are tapered. They are a smaller diameter at the open end. Torque them down too tight and the fitting will crack the housing.

Either go easy screwing it in or find a heater hose fitting that uses straight threads instead of pipe threads. (Good luck sealing that, though.)

ylose

I went with an aluminum water pump... :cheers: