Dave, Art, Kitty, et all,

Thanks for your responses.

It would appear that your experiences are different than mine. Other than this car my procedure has always been as follows:

1. Clean all the mating surfaces
2. Lightly coat the heater pipe, the heater pipe seal (sliding the seal back against the ridge), and the interior surface where the heater pipe lives with silicone sealer.
3. Put the paper gasket in place on the studs, insert the top seal in its groove, and coat the surface of the top seal with silicone sealer
4. Hang the water pump on the studs, push the heater pipe into the back of the pump and partially tighten the nut/bolt combination.
5. Install the nuts on the studs and tighten the nuts enough that the pump can still move up but eliminating the front to back movement.
6. Use whatever I can find room for to lever up the bottom of the pump. A length of sledge hammer handle is the most common, but if the belly pan is off I have been known to use a small bottle jack and a length of 2x4.
7. After the pump is raised enough to start the bolts I install them; tightening those and the nuts on the studs
8. Tighten the heater pipe bolt.

The suggestion of installing all but the bottom bolt baffles me. I have never been able to install any of those bolts without applying a significant effort at raising the pump with a lever under it. I make every effort to maintain that force while I am tightening the bolts, but I can't imagine being able to raise it any more than I already have to get the bolts started.

On this car it is very easy to get the bolts started by simply pulling up on it by hand. The seal is not compressing very much at all. When I (once again) reinstall this pump I will make every effort to lever the pump as much as possible to compress the seal.

As to the condition of the bottom of the head where the seal rides I will pay particular attention this time. However in cleaning the surfaces up and checking that surface by feel and with a small mirror I don't recall any concern on my part in the past. It did not appear that someone had taken a grinding disk to it or in any way distorted it.

I will admit to using after market reseal components. I can't find aftermarket gaskets any longer but have a Volvo gasket that I use as a pattern and then cut my own from a sheet of gasket material of the correct thickness.

If I install a new HEPU pump I will use the components that came with it. When I was going to try to work with this pump "one more time" I had contemplated applying an even 1/16" layer of silicone in the bottom of the groove to effectively raise the seal by that amount.

Randy
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Any twenty minute job is just a broken bolt away from a three day ordeal