V6 water pumps getting hard to find

[TJ's GMC]

Well mine finally started squealing after being on that engine for the better part of 30 years(far as I can tell) and I've noticed that they are getting harder to find. I called Napa, Orielly's, and Autozone all with a negative answer. Summit racing has them in stock so if anyone wants to grab one to have here is the link. Might be a good idea to stock up on a few spare new parts as the years go on because things are getting limited!

https://www.summitracing.com/parts/gmb-130-2835

[TJ's GMC]

I just ordered it today so I will follow up to confirm that it fits and all is fine.

[FetchMeAPepsi]

Thanks TJ! Last time i checked Rock Auto had some. Looks like they only have the gasket now.

Update: Looks like summit racing has them https://www.summitracing.com/search/part-type/water-pumps-mechanical/make/gmc/engine-size/5-0l-305
NAPA shows them in stock for ship-to-home, but not pickup around me https://www.napaonline.com/en/p/TWP42099?impressionRank=1

[Funky61]

TJ, that is the one I ordered for the 305D, and it fits.

[kknotts]

Mine was leaking a couple years ago and I was able to get it rebuilt locally for $35.00 or so. Working perfectly since.

[TJ's GMC]

Thanks TJ! Last time i checked Rock Auto had some. Looks like they only have the gasket now.

Update: Looks like summit racing has them https://www.summitracing.com/search/part-type/water-pumps-mechanical/make/gmc/engine-size/5-0l-305
NAPA shows them in stock for ship-to-home, but not pickup around me https://www.napaonline.com/en/p/TWP42099?impressionRank=1

Yeah I got mine from summit racing and I couldn't find one through Napa. That's awesome you were able to. How'd you find it? I typed in 64 GMC 1500 with the 305 v6 and water pumps wouldn't even pop up!

[FetchMeAPepsi]

Yeah I got mine from summit racing and I couldn't find one through Napa. That's awesome you were able to. How'd you find it? I typed in 64 GMC 1500 with the 305 v6 and water pumps wouldn't even pop up!

I just went through DuckDuckGo.com and searched for "1964 GMC Water pump napa"
Autozone had a result too but it showed as out of stock. Made me think they were planning on getting more in because it looked like a regular item page, but who knows. Hope so since they're cheaper than Napa most times.

[TJ's GMC]

I just went through DuckDuckGo.com and searched for "1964 GMC Water pump napa"
Autozone had a result too but it showed as out of stock. Made me think they were planning on getting more in because it looked like a regular item page, but who knows. Hope so since they're cheaper than Napa most times.

Copy that, I found it through Napa and list on it was $134 and with my shop discount $75. Summit has them for $48 so I'd go with them again for sure.

[George Bongert]

Copy that, I found it through Napa and list on it was $134 and with my shop discount $75. Summit has them for $48 so I'd go with them again for sure.

At the risk of having some mud thrown at me, buying parts from NAPA is akin to buying a Cadillac or Lincoln automobile. You're paying for the name, and not necessarily for the quality of the product. Sorry if I've ruffled any feathers, or offended anyone.

[TJ's GMC]

At the risk of having some mud thrown at me, buying parts from NAPA is akin to buying a Cadillac or Lincoln automobile. You're paying for the name, and not necessarily for the quality of the product. Sorry if I've ruffled any feathers, or offended anyone.

You definitely are not wrong there. Far as I could tell the pump from Napa and Summit are made by the same manufacturer and Summit is under half the cost.

[George Bongert]

You definitely are not wrong there. Far as I could tell the pump from Napa and Summit are made by the same manufacturer and Summit is under half the cost.


Yeah, and most likely they were BOTH made in China!! Seems that most aftermarket parts for our vehicles are made in China these days, which is a doggone shame. Replacement parts should be made in the USA, period!!

[Quigley]

Most of the time they are easily and economically able to be rebuilt.

[George Bongert]

Most of the time they are easily and economically able to be rebuilt.

It's just a matter of a new shaft, bearing(s) and a seal. Impellers very rarely go bad, if at all. But given that an existing water pump can be easily and economically rebuilt, what guarantee do we have that the shaft, bearing(s) and seal were not made in China??

[BobBray]

Summitt Racing does indeed carry the GMB 130-2835 with is the common V-6 water pump with the flange for the pulley and fan. NAPA still has these pumps, but for some reason they don't list them by application. If you use the GMB part number in the NAPA interchange, it crosses over to their TWP 42009. Currently NAPA has 20 in their system. BTW- TJ's is right, GMP is the water pump supplier to NAPA! It is the same pump.

[LEWISMATKIN]

bob, it's because NAPA no longer recognizes the unique differences between GMC & Chev. if you want to look this engine up in the cataloging, you have to go to the medium duty listings to actually find the engines.

[Troyport]

Sorry if I am hijacking this thread.. I need a water pump for my 68GMC with the 351, I looked at the Summit link, scrolled to the GM-130-2835, I assume this is the correct part? I read somewhere else that there may be a normal duty and a heavy duty, different bearing size.. I also considered rebuilding mine, I assume it just presses apart? Any thoughts or advice? Thanks.

[BobBray]

No problem! GMB 130-2835 is the 'light duty' pump, used on pickups and many medium duty V-6's. The big difference between this pump and the 'heavy duty' is just the way the pulley mounts. Light duty has the flange with 4 threaded holes, heavy duty has a keyed threaded shaft with no flange. The bearings may indeed be larger too, the shaft diameter is pretty big. Here is a link to a heavy duty pump for sale on Ebay (no connection to seller):

https://www.ebay.com/itm/175440758276

[Troyport]

Thanks for the reply. I found out yesterday, after much research and phone calls that there are actually 3 different water pumps. keep in mind that my truck is a '68 with the 351... But, there is the big one that is mounted higher, with the tapered keyed shaft, used on air brake trucks. On the light duty trucks, like my pickup, there are 2 different pumps. The light duty has a small snout bearing, used on manual power steering trucks. The easiest way to tell this pump is the gussets that support the snout are short. Then there is a heavier duty pump that has a bigger snout bearing. This has longer gussets. My truck has factory power steering, so the heavier pump. I suppose the lighter pump would be fine since I am not using this truck very hard, and I also suppose I could have lowered the power steering pump enough to just drive it off the crankshaft. Please keep in mind that I am just getting into these trucks, so I may not be correct? I would be interested in what others may think. And also I don't know what may have changed from the 60-66's to my generation of truck. - Mike.

[Troyport]

I should add that both pumps I referred to above have the 4-hole flange for the fan and pulley.

[tbucketnut]

Be nice to see examples of both of the pumps

[Troyport]

Here's some pictures of the 3 different pumps. I have no affiliation with this ebayer, but I think it is the cleanest way to see the differences. There's also a really inexpensive one that has the bigger gussets, kinda looks like the medium duty, but it is made out of aluminum and therefore very light duty. Keep in mind I am no expert, I could be totally wrong. Would love any feedback - P.S. - on my previous post, I said the light duty water pump is for "manual power steering". I meant to say "no power steering"

10154

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10156

[BobBray]

My '67 351E (no power steering originally) had the iron pump with the short gussets on it before I rebuilt the engine. No idea if it had ever been changed. I replaced it with a NAPA 42099 which is iron with the long gussets like the one in the second picture. The NAPA 40299 appears to be identical to the GMB 1302835. The 1967-68 GMC light duty parts catalog shows part #8875385 as the water pump for all 305 and 351 V-6's.

[Troyport]

Hi Bob, yes, that GMB1302835 does appear to be the correct pump, that is the heavier-duty of the light duty pair. Looks like that is no longer available, at least from what I can see. Summit claims to have it in stock, until you click the box, then there is an estimated delivery date of a few weeks out. I called them, and they could give no definitive answer. If someone knows where to get them, especially for the price of around 60 bucks, I sure would love to know! Or, if someone just put on the lighter-duty pump in place of this one, I would also love to know how it worked out. Since this truck is no longer a farm workhorse, I figure it would be just fine. Heck, could buy 2 for the price of the rebuild kit on ebay if they don't last long. Or again, relocate the power steering pump to just run off the crank. What does everyone else do?

[LEWISMATKIN]

here's some pictures of the 3 different pumps. I have no affiliation with this ebayer, but i think it is the cleanest way to see the differences. There's also a really inexpensive one that has the bigger gussets, kinda looks like the medium duty, but it is made out of aluminum and therefore very light duty. Keep in mind i am no expert, i could be totally wrong. Would love any feedback - p.s. - on my previous post, i said the light duty water pump is for "manual power steering". I meant to say "no power steering"

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10155

10156 the top pump is for engines with air brakes, the lower is for engines w/o air brakes

[lizziemeister'sV6]

Correct me if I'm wrong - but I'm pretty sure 1955 - 1963 Pontiac V8's share the same water pump as the GMC V6 lighter-duty engines.:winter:

[BobBray]

The Pontiac pump looks similar but does not interchange.

[lizziemeister'sV6]

Thanks Bob - had an old timer tell me that when he inspected my 65 Suburban - said GMC used Pontiac V8's in the late 1950's and they carried on the use of the same waterpump when the V6 was developed.:signthankspin:

[LEWISMATKIN]

The pontiac pump had a different impeller---all aftermarket replacement new pumps use the gmc impeller in both applications. I have had both and the gmc pump will install on the early '63 pontiac timing cover.

[lizziemeister'sV6]

The pontiac pump had a different impeller---all aftermarket replacement new pumps use the gmc impeller in both applications. I have had both and the gmc pump will install on the early '63 pontiac timing cover. If I'm understanding it right - a NOS Pontiac pump will not work on a GMC because of the impeller clearance - but an aftermarket pump will fit either the Pontiac and GMC - so the housings are the same. Is the Pontiac impeller deeper, larger around or what. So the old guy was correct in a way.:thumbsup:

[LEWISMATKIN]

the pontiac impeller has somewhat taller blades, they are shorter in length, and are turned the opposite direction than the GMC pump. the pontiac impeller also has 3 large holes that surround the hub of the impeller.

[Prowbar]

the pontiac impeller has somewhat taller blades, they are shorter in length, and are turned the opposite direction than the GMC pump. the pontiac impeller also has 3 large holes that surround the hub of the impeller.

Opposite direction? Rotation-wise or the way it pumps inside? The vanes face the same direction for the GMC and Pontiac pump?

[BobBray]

Pontiac V-8's up to 1959 had reverse-flow cooling, maybe that explains the different impeller:

http://www.pontiacsafari.com/EngineCooling/

[Prowbar]

Interesting. Though the aftermarket water pump (GMB 1302835) I bought from Rockauto for a 1963 Pontiac Tempest with the 326ci V8 (which is past 1960, so the correct cooling system) is the suitable water pump for a light-duty V6. Vanes face the same way, and it is a direct bolt-in.

[BobBray]

BTW, Summit Racing has the GNB 130-2835's back in stock.