1988 water pump - correct hub

[John G.]

I've removed the water pump casting # 14047008 from my California 1988 Anniversary automatic. The hub is different than any water pump offered for sale in that it has studs. I've owned this car for about 20 years so I'm assuming it's the original water pump. Is it? Is there a judging difference if I use a water pump that requires bolts?

Any idea why there is such a heavy round "plate" (7.95 lbs) on the front of the water pump?

I'm also looking for a Florida shop that rebuilds this type of pump.

[Larry M.]

Re: 1988 water pump - correct hub

John:

Two things come to mind when I view your pic:

1. Most WP hubs can be removed and reused. This may be an option for you.

2. You can make studs yourself and use them. The originals look pressed in like a wheel stud, but you could make your own threaded studs for a WP that has threaded connections for bolts.

Outside of that I can't help.

Larry

[John G.]

Re: 1988 water pump - correct hub

After parts book research the GM P/N is 10048919 and the studs are 382919. But parts manual also shows 14067335 bolts. The pump is discontinued. Options appear to be to send it to Cool Guy or buy a GM reman and use bolts. The bolt option is way easier and I doubt I'd lose than 1 point.

[Joe L.]

Re: 1988 water pump - correct hub

I've removed the water pump casting # 14047008 from my California 1988 Anniversary automatic. The hub is different than any water pump offered for sale in that it has studs. I've owned this car for about 20 years so I'm assuming it's the original water pump. Is it? Is there a judging difference if I use a water pump that requires bolts?

Any idea why there is such a heavy round "plate" (7.95 lbs) on the front of the water pump?

I'm also looking for a Florida shop that rebuilds this type of pump.

John------


The hub on your waterpump is exactly correct. The studs are not an integral part of the hub. They are threaded into the hub and can be removed by turning them out.

Your waterpump is correct for your application. The part number (NOT the casting number) was GM #10048919. It was discontinued in September, 1993 and replaced by GM #12522035. The latter was also discontinued several years ago and replaced by GM #19168607 which remains available. As far as I know, the 10048919 and 12522035 were virtually, if not absolutely, identical. I believe the 19168607 might be a bit different in some minor ways. It will be 100% functional, though. In any event, your best bet might be to have your pump rebuilt.

The "heavy round plate" you mention is a vibration dampener. I'm not sure if it was used on all 1988's or just those also equipped with automatic transmission. In any case, your car should have one. It was originally GM #10105208 which was discontinued in June, 1990 and replaced by GM #10105252. The latter has been discontinued for a few years. You don't want to need one as NOS examples can be hard to find.

As far as bolts versus studs, it's not completely clear. The GM #14067335 bolt was used for 1987 and all or part of 1988. This bolt was a flanged , non-trimmed (i.e. non indented) head bolt of thread size 5/16-24 and 7/8" thread length. It was phosphate finished. It was discontinued from SERVICE in February, 1999.

The studs used were, indeed, GM #382919. This stud is 1-1/4" overall length, 5/16-18 thread on one end and 5/16-24 thread on the other end. If your studs agree with this, then I'd say these are absolutely original to the car, especially since you've owned it for 20 years and it's unlikely they would have been changed prior to your ownership.

[John G.]

Re: 1988 water pump - correct hub

Thanks for all the detailed information. It seems funny to have the heavy plate as other years of C4s are different - I'll obviously reinstall it.

[Joe L.]

Re: 1988 water pump - correct hub

Thanks for all the detailed information. It seems funny to have the heavy plate as other years of C4s are different - I'll obviously reinstall it.

John-----


The dampener was used from 1988 through 1991.

[John G.]

Re: 1988 water pump - correct hub

Interesting morning. Order a "supposed" correct NAPA brand water pump. Didn't have weigh scale with me but it was significantly heavier than the original - I'm guessing thicker walls as with the C1 pumps that have flow problems. With dial caliper some measurements were slightly different but likely usable. But the hub was pressed in further - counter person said the same pumps were sold for psgr car 305 and 350 engines. I mailed by old pump to Arizona to get refurbed. Should have it back in about 10 days.

[Joe L.]

Re: 1988 water pump - correct hub

Interesting morning. Order a "supposed" correct NAPA brand water pump. Didn't have weigh scale with me but it was significantly heavier than the original - I'm guessing thicker walls as with the C1 pumps that have flow problems. With dial caliper some measurements were slightly different but likely usable. But the hub was pressed in further - counter person said the same pumps were sold for psgr car 305 and 350 engines. I mailed by old pump to Arizona to get refurbed. Should have it back in about 10 days.

John------


Are you sure the NAPA pump was not a pump with a cast iron housing? That's the only reason I can think of for it to be significantly heavier. If it was aluminum, as original, I don't think that "thicker walls" would have made much difference in weight. In addition, I don't think that passenger car small blocks used an aluminum pump as did Corvette. The passenger car pump would probably work OK assuming the hub spacing was the same as Corvette but it sounds like, from your description, the hub spacing is different.

[John G.]

Re: 1988 water pump - correct hub

The hub spacing from what would be the block face was noticeably less. I didn't test with a magnet but I quit when I saw the hub difference. The color was darker gray than the GM casting. I could probably have made it lighter with paint. Thought for about 10 seconds about putting in in the press and moving the hub but decided to not do that. They said it was made in New Jersey but who knows - maybe assembled in NJ with imported components. The '88 will sit there while I wait. Maybe I'll work on my '61 transmission some more.