C1 Waterpump

[Christopher R.]

I'm scavenging a $2 swap meet Chevy waterpump for parts. Looks exactly like a C1 and C2 waterpump. Painted orange. Has the 90 degree outlet at the top. The curved outlet on the side. I bought it for these fittings. Never realized I'd want it for the backing plate and the attaching bolts.

Son-of-a-gun. I can't get a wrench or socket on the back cover attaching bolts. 3/8 is just a tad too small. 7/16 is way too large. I kept trying them, figuring the heads were either munged up or too big from the paint. But no. So I tried a 10 mm wrench. Fit perfectly. Wha???? Metric fasteners on an early Chevy??? Measured the bolt. It is as it's supposed to be, 1/4-20x3/8.

It's a 1/4-20x3/8 bolt. But with a 10mm head. The head is also indented. The number "88" is embossed in the head. It's plated that brass color. The bolt does not have the captured Sems washer as the original. But the head does have broad shoulders (I forget that term.).

Ever hear of metric headed fasteners on an early Chevy? These bolts are hard to see when installed. If I use them, do you think I'd have the only C1 with metric fasteners? Is there an award for that? Shiver-Oh-lay returning to it's French roots award???

[Mike E.]

Re: C1 Waterpump

That pump has been rebuilt some time in the past, and the fasteners are incorrect. I can assure you, they didn't use a metric head on any solid axle. Clutch heads, yes--metric, no!

[Bernard M.]

Re: C1 Waterpump

The correct fasteners for the backplate would be 1/4-20 slotted pan head screws. The backplate should be a flat metal plate, not pressed and formed sheet metal. If the head is metric, what is the thread?

[Mike E.]

Re: C1 Waterpump

Bernard--
Can't agree with you on the 609 water pump, which is, I believe, the one he's talking about. (Top bypass) Most 609's had turned-edge back with hex nuts in 62.

[Christopher R.]

Re: C1 Waterpump

Yes, I've got a "609" waterpump casting that I'm trying to configure to put on my '62. The "609" is apart in a box full of fittings, backing plates, and backing plate fasteners. I'm mixing and matching these parts to come up with a "609" waterpump that won't leak. I'm also scavenging some parts from an unknown waterpump I found at a swap meet. For the "609", I'm going to use the turned back edge backing plate with hex nuts. The SAE bolts with the metric heads threw me for a loop. Never saw that before. I knew there were metric fasteners in later cars, but I thought by the time they used metric fasteners, the engines weren't painted orange anymore. Thanks for all your help.

[Bernard M.]

Re: C1 Waterpump

I guess I should have read the profile to see we were discussing a 62. Most of my efforts are directed toward red painted pumps (56) instead of orange painted ones. I have rebuilt several 3704911 pumps and been able to purchase the seal from Grainger (PAC-SEAL 1R324 I think) and the bearing from a local bearing supply (FAG W-2468 or NSK 885118). If you get desperate, I have a couple of the formed steel plates you'd be welcome to. I'm including a link to a good reference article.




Water pump rebuild

[Joe L.]

Re: C1 Waterpump

chris-----

I have never, ever seen or heard of screws or bolts with SAE thread size and metric head size. I suppose it's possible that these might be used by rebuilders. If so, though, they must have them specially made and I can't imagine why. It might be that one of the metric threads sizes is very close to 1/4-20 and "will work". I can't say that, for sure, since I've never tried it.

No metric fastners were used on small blocks with ONE exception. That exception is spark plugs (which are 14 mm).

By the way, the blot head that you describe are called "flange head"