wag

My dad who was a mfg engineer always re checked a rebuilt or new waterpump in this manner, not trusting anyone, especially in a "Rebuilding Plant". I do it all the time since I had a rebuilt pump from a 70 Vette fail. In the 5 or 6 waterpumps that I have put on my 85s in the past 21 yrs, one failed. All it takes is one, and one is too many. Procedure:

Clamp fan side flange in heavy towel in a vise. Use 2 large pair pliers grabbing opposite side of the propeller, holding firmly, give it a good tug back and forth. Mine was OK on the first tug, but on the opposite tug, it came loose just a little bit. Then I gave it another tug loosing it up more, then I popped it off the shaft with a large screwdriver. I can only imagine what a royal mess this would have been if I had installed this pump.

Hope this helps someone. It works for me.

SwayBar

Just curious, did you try this on the water pump you've removed, too?

G Man

Wow, that really makes you wonder about which brand to trust. I have been reading about people who actually rebuild their own water pumps. I wonder if this would be possible with a 928 WP. Seems the bearings and seals are all that is replaced and those should be available from the parts counter. Not many tools needed either. A small press was about the only special item needed. Just a thought.

wag

SwayBar: I do this, before the pump goes on, afterwards, it makes no difference.

My dad used to rebuild his own water pumps and we did it on my old Vette too, but getting the seals were the big issue in getting them, so our rebuilding came to an end. I can imagine trying to get the seals for our Porsches, would be all but impossible.

leperboy

I think what Swaybar is getting at is: will a good water pump also do this. Will a water pump that's proved to work and not fail after xxx miles also come apart using this test?

The only way to know if you can determine good from bad water pumps this way is to know if only bad ones will separate with this test. I think that if you apply enough force that any press-fit impeller would separate.

Maybe someone with a few old pumps could test them and see what percentage would come apart this way. Then the question would be what is the likelihood those that came apart would have failed. I don't know an easy way to test that.

Matt

wag

Evening Guys: I only give the impeller a tug one way, then the other. These are usually just pressed on and or with metal impellers, heated then put on the shaft. I see no reason as to why if you have the WP off the car to check it out.... but..... after going through all that work to do it and the beer consumed plus the hot wings & baby back ribs while your doing this job... put on a new one??? It is the weakest link in the 928. After 45m, there ready to come out anyway and is a good opportunity to get the wife to buy more beer, wings, ribs....