Hi

The water pump on my 235 just went, and I am having trouble finding a replacement. The 235 is from 58 to 62 era, and the casting number on the pump is 3736567. The parts supply house brought in a number of pumps, but they all had a longer shaft (about 1" too long). The casting numbers on the new pump were the same as mine. Has anyone had this same issue?

Dear 56;

You may have a "short shaft" pump.

These are 'custom made' so the 55-62 engines can fit into the early model (37-54) cars/trucks W/O modifying the radiator etc.

Patrick's will have one.

Good luck, John M.......

Don't pay those outrageous prices for the short shaft water pumps. Take one the the new pumps and press the hub further on the shaft to the same measurement as your old one. Cut off the shaft leaving enough to support the pulley and fan blade. Just did this on a pump for a 261 going in a 55 1st series. Saved about $100 bucks for less than an hour of time.

This sounds like a good idea. Is there a good way to press the pulley down the shaft? Then cut with hack saw?

I just payed another visit to the parts store to see if I could modify the long shaft pump, but it seems unlikely.
The hub and the 4 holes are different from my existing pump. Now I am really baffled. It appears that my existing pump was modified, so now I have no idea what I have. If I order a short shaft pump from Patricks, will the hub match up with my pulley and fan, and line up with the other pulleys.

I'm sure it will, but; You need to call Patrick's and discuss this with them.

As I recall I/we/they put the 'early pulley' (1937-54)on the 'later' (55-62)pump shaft.

JM.....

PS: If you try this yourself, be carefull not to move the impeller away from the pump housing, as it will leak etc.

What diameter is the pulley you currently have, and what size is the fanbelt?

When they changed pulley sizes, they also changed the belt size, which also affects the balancer.

The pump you have is a shortened one for 55-62.

I believe the Patricks kit comes with the larger diameter pulley and smaller fan belt like what you would expect to see on a 55-62 engine, but that doesn't mean you couldn't adapt the earlier stuff, should you need to. Just check with Patricks first.

There is also an adapter plate somebody is selling on Ebay to use the 53-54 type pump on the 55-62 block for about $40 should you want to run the larger belt and not have to use modified "wear" parts (the pump).

I did some research on the Web and was surprised by the huge price difference between the water pums.

Classic Chevrolet Parts stock pump: $99,-
Chevs of the 40s (short shaft): $ 85 + 35 core
Patricks and Langdon (short shaft): about $ 100
Chevy Duty stock $ 49/short shaft $139

and the winner is:

www.Autopart.com stock pump: $ 25,95 + 4 core

I wonder what makes the huge differences?
O.K. the short pumps come with a special pulley but that does not make the almost $100 difference.

Sending your old pump UPS to them (Patrick's) would be the fastest way to "get it right", the first time.

Good luck, John M.......

Frank,
What you are forgetting is the labor charge that's involved in taking the stock pump and modifying it. The only way you will ever get a short shaft pump for cheap is if you know somebody that can do it for you for nothing, or if you do it yourself.

Also, in general, specialty parts places trend a little higher in price than a NAPA, etc... especially when you consider shipping charges and the extra waiting you go through to get the mail order parts. Sometimes where the parts are made will affect the price. Sometimes parts made in Asia can be less reliable than ones made here in the U.S.

Personnally, I am not in favor of modifying wear parts unless it's the only way to make something work. As I have said before, there is more than one way to deal with the water pump issue. It's up to you to figure out what works best for you.

As for buying a press, I have found that Harbor Freight runs sales on there presses fairly regularly. If you are finding yourself taking in driveshafts for U-joints, rearends for bearings, or T5 tranny rebuilds, then you have probably spent more than it would take to buy a good press and do all of it yourself. Just a thought...