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7/8" Heater Hose Nipple on Water Pump?

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Scrappy View Drop Down
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    Posted: Jun/02/2023 at 7:28pm
So, I'm trying to get the Spirit running for Hot Rod Power Tour and was almost complete on getting the 401 buttoned up so I could fill the cooling system, but couldn't get the heater hose onto the water pump nipple. 

The heater core outlet is 3/4" and the hose that was on there (which I had to cut off because it wouldn't budge) was 3/4", so I'd bought 3/4" hose to replace it.  I had to resort to pulling the alternator and that side of the Bulltear serpentine setup to get adequate access, only to discover that the nipple is ~7/8".

It looks as if 7/8" heater hose is available, but I'm not coming up with any barb reducers, and even McMaster-Carr doesn't show 7/8" barb fittings.

What gives?  Any suggestions?  Confused

Thanks,
Scrappy

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Trader View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Jun/02/2023 at 7:50pm
Are you referring to these:
?
I use a Wirsbow plumbing tool to expand the 3/4" heater hose with a little silicone grease. Have the tool already from previous work so it does double duty. Example:
Know any plumbers?
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Scrappy Quote  Post ReplyReply Direct Link To This Post Posted: Jun/02/2023 at 8:05pm
Nope, I'm not referring to a clamp.  I'm referring to a metal barb fitting that you'd fit a hose onto, such as:  https://www.mcmaster.com/products/hose-fittings/metal-barbed-hose-fittings-for-air-and-water/

Originally posted by Trader Trader wrote:

I use a Wirsbow plumbing tool to expand the 3/4" heater hose with a little silicone grease. Have the tool already from previous work so it does double duty. Example:
Know any plumbers?

I do know some, but am reluctant to stretch out the hose.  Obviously, one was stretched to fit, but I fear a failure where replacing it would be a major PITA.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sweatlock Quote  Post ReplyReply Direct Link To This Post Posted: Jun/02/2023 at 8:10pm
Is this an aftermarket water pump? You won’t have an issue with a rebuilt original casting, but I’ve noticed that the aftermarket water pumps have oversized nipples (insert joke here). Same thing with the aftermarket thermostat housings - apparently when they were designed no one bothered to measure an original or they were never intended to be used with hoses installed. Either that or the casting molds have worn and everything’s grown. 

Edited by sweatlock - Jun/02/2023 at 8:12pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Scrappy Quote  Post ReplyReply Direct Link To This Post Posted: Jun/02/2023 at 8:20pm
Originally posted by sweatlock sweatlock wrote:

Is this an aftermarket water pump?

I have no idea.  It was installed years ago by someone else and that person can't be asked, but knowing him, it was likely from NAPA.

I can tell with certainty that it ain't an Edelbrock.  If it were, I wouldn't be dealing with the issue, I'd just change the nipple.
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Post Options Post Options   Thanks (3) Thanks(3)   Quote THE MENACE Quote  Post ReplyReply Direct Link To This Post Posted: Jun/02/2023 at 10:33pm
Originally posted by Scrappy Scrappy wrote:

So, I'm trying to get the Spirit running for Hot Rod Power Tour and was almost complete on getting the 401 buttoned up so I could fill the cooling system, but couldn't get the heater hose onto the water pump nipple. 

The heater core outlet is 3/4" and the hose that was on there (which I had to cut off because it wouldn't budge) was 3/4", so I'd bought 3/4" hose to replace it.  I had to resort to pulling the alternator and that side of the Bulltear serpentine setup to get adequate access, only to discover that the nipple is ~7/8".

It looks as if 7/8" heater hose is available, but I'm not coming up with any barb reducers, and even McMaster-Carr doesn't show 7/8" barb fittings.

What gives?  Any suggestions?  Confused

Thanks,
Scrappy


Mopar/Jeep hose #J576 5301 is a 3/4" hose with one end molded 7/8" for the water pump. 
 
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70 Javelin 401, 727 (Wife's)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Scrappy Quote  Post ReplyReply Direct Link To This Post Posted: Jun/03/2023 at 3:50am
Originally posted by THE MENACE THE MENACE wrote:

Mopar/Jeep hose #J576 5301 is a 3/4" hose with one end molded 7/8" for the water pump. 

Wow, that info is just the ticket!  In case I run into a parts guy/gal who can't look it up that way, do you know the application so they can look it up by year/model/engine?
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pit crew View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote pit crew Quote  Post ReplyReply Direct Link To This Post Posted: Jun/03/2023 at 5:56am
Originally posted by Scrappy Scrappy wrote:

Wow, that info is just the ticket!  In case I run into a parts guy/gal who can't look it up that way, do you know the application so they can look it up by year/model/engine?
1986 Jeep J20 or Grand Wagoner

73 Hornet - 401EFI - THM400 - Twin Grip 20
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Scrappy View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Scrappy Quote  Post ReplyReply Direct Link To This Post Posted: Jun/03/2023 at 5:57am
Originally posted by pit crew pit crew wrote:

1986 Jeep J20 or Grand Wagoner

Thanks!
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Post Options Post Options   Thanks (1) Thanks(1)   Quote JohnRyd Quote  Post ReplyReply Direct Link To This Post Posted: Jun/03/2023 at 6:15am
If you have no luck getting the Jeep hose you may want to consider a short 7/8 x 3/4 reducer hose, then a 3/4 hose splicing nipple connecting the 3/4 end of the reducer to a length of 3/4 heater hose going to the heater core. Or you could put the smaller end on the heater core, use a 7/8 splicing nipple and run 7/8 hose to the pump.

If you search for 7/8 x 3/4 hose a few reducers come up. They are typically about 6 inches long. If you search 7/8 x 3/4 heater hose, several molded heater hoses for other applications come up. Most are short and have several bends. You would probably need to cut it to get the section that works.

If you search 3/4 splicing nipple several of those come up.
 
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