Rebuilt 3859326 Water Pump Today

[Joe C.]

The first photos show a "rebuilt original" pump from one of the well known Corvette specialty parts houses. This pump had less than 1500 miles on it, and was installed on a now-disassembled 1965 L76 engine in 2002. The bearing had already begun to develop slop.

The "old" bearing prominently displays "China", and the impeller was a 2 piece stamped steel replacement assembly. The hub was the reused, cast original. It is NOT ADVISABLE to reuse a water pump hub despite the "correctness" aspect. The backplate was the deeply pitted, flat, original sheet steel plate.

[Joe C.]

Re: Rebuilt 3859326 Water Pump Today

More of what came out:

[Joe C.]

Re: Rebuilt 3859326 Water Pump Today

What went back in, is a F.A.G. bearing, made in North America (Canada), new F.A.G. seal, new cast iron impeller with matched back plate, and new billet steel hub. The pump was originally manufactured with a cast iron impeller of slightly different design enabling use or the flat back cover plate, shown.
The new impeller was very mildly touched up with a die grinder to remove some of the casting roughness.
The same treatment was performed on the housing internals and pump hub and volute.
Internal holes were drilled and expanded, and casting flash was removed to streamline obstructions.
All mating surfaces were hand filed to remove pitting and obtain flat surfaces, then checked for flatness on surface plate, and rechecked on engine block and cover fitted.

[Joe C.]

Re: Rebuilt 3859326 Water Pump Today

Nearing completion:

[John D.]

Re: Rebuilt 3859326 Water Pump Today

Joe,

Thanks for sharing. What are the bearing and seal part numbers you used and where did you get the new shaft ?

john

[Mark P.]

Re: Rebuilt 3859326 Water Pump Today

Did you rebuild it yourself ? Any special tools needed, like a press ?

[Joe C.]

Re: Rebuilt 3859326 Water Pump Today

Joe,

Thanks for sharing. What are the bearing and seal part numbers you used and where did you get the new shaft ?

john

http://www.hemmings.com/classifieds/servicesoffered/na/unspecified/812925.html

He is very well respected, especially among racers and vintage car restorers. You would not believe the price that I paid for the above items (bearing/seal/cover plate/hub/impeller/gaskets/bolts), which are all the finest quality parts.

[Joe C.]

Re: Rebuilt 3859326 Water Pump Today

Did you rebuild it yourself ? Any special tools needed, like a press ?

One word of caution for anyone willing to do this themselves: DO NOT, ever, support the pump by its mounting flanges at any time during any pressing operation. If you do so, you risk cracking the housing.

There are two critical measurements needed: engine mount flanges to pulley mount surface of hub MUST be 5 11/16" (plus/minus .005") for Corvette applications, and impeller vane to volute (housing) clearance must be within .010 and .035. Most of the required info is found in the Shop Manual.

The disassembly was done in my garage, using a 6" bench vise, 1" bar stock, a MAPP gas torch, and various sockets. I media blasted and assembled in my friend's machine shop, using his blast cabinet, a 5 ton press and various fixtures/items that I found in his shop. No "special" fixtures are needed, and can be improvised from whatever is lying around. The assembly can be done in a large vise with assorted sockets, pins, etc. You will need a press to install the new hub onto the pump shaft............if it presses on too easily, then something is not right.

Many thanks to Wayne Midkiff, who supplied some vital dimensions, and to Joe Lucia, who provided the necessary information which caused me to hunt for the F.A.G. manufactured bearing and seal.

Joe

[David D.]

Re: Rebuilt 3859326 Water Pump Today

Joe,
Absolutely GREAT post with pictures....I have the very same, supposedly and correctly rebuilt, 326 H2o pump, but which is going on an early '64 L76. I am now wondering if I shouldn't visit this man, who actually lives here in the 'same' state.....
Again thanks,
David

[Joe C.]

Re: Rebuilt 3859326 Water Pump Today

His name is Howard Stewart, and I recommend him highly. He is honest, his prices are fair, indeed, low, and he has 30 plus years experience.

https://www.howardstewartrestorations.com

The price he charged me for those parts was ONE THIRD the price that a "famous" Corvette pump builder was asking. He also quoted me a very cheap $100.00 plus S&H to rebuild my pump, which I declined.

If your pump was rebuilt at some time in the past, you can usually tell if it has been fitted with a stamped steel impeller by checking if it still has the original, flat cover in place. The original style, cast iron impeller, which fits under the original, flat cover is no longer made. Updated (and superior) cast iron impellers are used with the relieved cover because they need about 1/8" more depth. They will pump more capacity than the original impeller. If you want to hide the new impeller under the original cover you must machine about 1/8" out of its depth. This, of course, reduces its capacity.

Joe