leak at water pump mounting gasket

[40cpe]

I bought this car a few weeks ago knowing It needed a few items sorted out. On a 272" Y-block, the water pump is leaking at the bottom of the mounting gasket between the two lower bolts. I removed all the added bracketry of the PS pump, alternator, AC compressor, etc, and removed the pump. I got both surfaces surgically clean, permatex #2 on a new gasket and mounting surfaces, and put it back together. Still drips from the same place. I didn't think to try to determine if one of the surfaces is uneven when I had it apart, but with the mating surfaces round between the bolt holes it might be difficult with a straight edge. Both surfaces appeared smooth and even while cleaning them. The water pump was new at the engine rebuild, and with all the inferior products we get today I wonder if it is the culprit. Any suggestions on getting a good seal when it is replaced again would be welcome.

 

[dmsfrr]

Double check that the leak isn't coming from a weep hole under the pump shaft.
If it is, a pump shaft seal is leaking.
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[fordor41]

Try sealing the bolts threads. they may pass into the water jacket. I've had that problem with SBF's and now I always use sealer on the threads.

 

[Daves55Sedan]

The bolt hole right above the timing pointer definitely goes all the way thru to the water jacket, so you need to at least seal the threads of that bolt with pipe thread sealer. Maybe do both the lower bolt holes just to be sure.
Your gasket and sealer is probably okay as is.

 

[willowbilly3]

I sometimes use a sanding block on those gasket surfaces. High spots will show up pretty fast. Sometimes the area around a bolt hole is pulled up a little from overtightening. After all, it's probably passed through quite a few mechanics in 60 years.

 

[40cpe]

It is definitely coming from the parting line between the pump and the timing cover. The drop forms and falls from that spot. I can see it really well. No evidence of seepage from the weep hole. Thanks Willobilly for that thought. I pulled it back off and ran a flat file lightly across the surfaces. The timing cover looked flat, but see the picture to see the high spots at the mounting holes and notice the still-dull spot near the left hole in the picture. That is the spot the water came from.

 

[dmsfrr]

It looks like a prev owner might have over torqued the water pump bolts and bent the pump cover.

 

[40cpe]

It looks like a prev owner might have over torqued the water pump bolts and bent the pump cover.

I really don't know, but not knowing any history, I'm suspicious of off shore reproduction.

I have new gaskets coming tomorrow. I'm going to put it back together with #1 Permatex and see if it will hold. It is supposed to bridge irregularities and harden in place.

 

[dmsfrr]

The same kind of thing happens to the mounting ears on exhaust manifolds and to the bolt flange of oil pans. The metal gets bent under the bolt heads, then the space between them leaks.

.

 

[40cpe]

update: after filing the surface flat(er), I put a new gasket and Permatex water pump and thermostat housing sealer on it. Probably overkill, but I ran it down the highway to get the radiator pressurized and no leaks yet! Hopefully one more project ticked off.

 

[rick55]

When fitting the thermostat housing to the manifold make sure your bolts are not too long. They will bottom out in the hole. I chased a leak there for ages before I realised the bolt was about 1/32" too long to pull the housing tight enough to seal.