What did this GM vacuum pump originally come on?

Bob Dunahugh

New member
Sep 17, 2012
2,784
4
3
I bought it at a GMCMI event. My problem is that I didn't think about the fact that the wiring plug wasn't there. And I don't know what it came on to find out how to wire it. The 4 terminals are labeled A B C D. The part number on the end is 5048679. There are two ports. With one labeled outlet on a funnel shaped piece. Does the outlet port go to the brake booster?
 
Bob, Can you put power to it and identify which port performs which function? Perhaps a photo might help someone identify it from men's mall shopping
trips.
Tom, MS II
--
1975 GMC Avion
KA4CSG
 
Bob
That is a pump that many of us used a few years back.
They can be found on the following vehicles (it is
hid under the battery tray on the
drivers side)
Buick Skyhawk (Body style J) -1982
Buick Skyhawk (Body style X) - Years 82
Chevy Celebrity (Body style A) Years 84-86
Chevy Caprice (Body style B) 1982
Chevy Cavalier (Body style J) 1982
Chevy Citation (Body style X) Years 82-85
Olds Cierra (Body style A) 1986
Olds Firenza (Body style J) 1982
Olds Omega (Body style X) Years 82-84
Pontiac 6000 (Body style A) Years 85-86
Pontiac J2000 (Body style J) 1982
Pontiac Phoenix (Body style X) Years 82-84

I found that it was also used by Volvo volvo --760-GLE TURBO (GAS) --1985 and 1987. Thet are located under the hood riht on top of the engine on the driver’s side.

If you can find one of the old cars you should be able to get the plug you need. You want the suction port to go to the booster and the other (I assume it would be called the outlet) to the manifold on the engine.

One problem with this pump is that it really doesn’t put out enough vacuum for the GMC motorhome.
I switched to the Long pump which was from a Ford electric car (Azure) but that pump is no longer available. That pump puts out a lot more vacuum.

Emery Stora
>
> Bob Dunahue posted:
> I bought it at a GMCMI event. My problem is that I didn't think about the fact that the wiring plug wasn't there. And I don't know what it came on to find out how to wire it. The 4 terminals are labeled A B C D. The part number on the end is 5048679. There are two ports. With one labeled outlet on a funnel shaped piece. Does the outlet port go to the brake booster?
> _______________________________________________
 
That should have read "Lenzi" pump, not "Long" pump.

Emery

Begin forwarded message:

> From: Emery Stora
> Date: February 24, 2017 at 5:22:37 PM MST
> To: gmclist
> Subject: Re: [GMCnet] What did this GM vacuum pump originally come on?
> Reply-To: gmclist
>
> Bob
> That is a pump that many of us used a few years back.
> They can be found on the following vehicles (it is
> hid under the battery tray on the
> drivers side)
> Buick Skyhawk (Body style J) -1982
> Buick Skyhawk (Body style X) - Years 82
> Chevy Celebrity (Body style A) Years 84-86
> Chevy Caprice (Body style B) 1982
> Chevy Cavalier (Body style J) 1982
> Chevy Citation (Body style X) Years 82-85
> Olds Cierra (Body style A) 1986
> Olds Firenza (Body style J) 1982
> Olds Omega (Body style X) Years 82-84
> Pontiac 6000 (Body style A) Years 85-86
> Pontiac J2000 (Body style J) 1982
> Pontiac Phoenix (Body style X) Years 82-84
>
> I found that it was also used by Volvo volvo --760-GLE TURBO (GAS) --1985 and 1987. Thet are located under the hood riht on top of the engine on the driver’s side.
>
> If you can find one of the old cars you should be able to get the plug you need. You want the suction port to go to the booster and the other (I assume it would be called the outlet) to the manifold on the engine.
>
> One problem with this pump is that it really doesn’t put out enough vacuum for the GMC motorhome.
> I switched to the Long pump which was from a Ford electric car (Azure) but that pump is no longer available. That pump puts out a lot more vacuum.
>
> Emery Stora
>>
>> Bob Dunahue posted:
>> I bought it at a GMCMI event. My problem is that I didn't think about the fact that the wiring plug wasn't there. And I don't know what it came on to find out how to wire it. The 4 terminals are labeled A B C D. The part number on the end is 5048679. There are two ports. With one labeled outlet on a funnel shaped piece. Does the outlet port go to the brake booster?
>> _______________________________________________
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Bob,
As luck would have it you can build your own connector;-)

Napa #s
725267
https://www.napaonline.com/napa/en/p/NW_725267/NW_725267
725170
https://www.napaonline.com/napa/en/p/NW_725170/NW_725170
725152
https://www.napaonline.com/napa/en/p/NW_725152/NW_725152

http://bdub.net/gmcmotorhome.info/figs/vacpump/vac.html

This is what you were looking for:

Connection A (Red wire) battery positive, 12 volts+ through a fuse.
Connection B (Black with white stripe) ignition positive, 12 volts+
Connection C (plugged) not used (not used in factory system either)
Connection D (Black wire) ground, 12 volts-
 
Forgot to include this note:

Try to use multi stranded wire as a single wire is very stiff.

> Bob,
> As luck would have it you can build your own connector;-)
>
> Napa #s
> 725267
> https://www.napaonline.com/napa/en/p/NW_725267/NW_725267
> 725170
> https://www.napaonline.com/napa/en/p/NW_725170/NW_725170
> 725152
> https://www.napaonline.com/napa/en/p/NW_725152/NW_725152
>
> http://bdub.net/gmcmotorhome.info/figs/vacpump/vac.html
>
> This is what you were looking for:
>
> Connection A (Red wire) battery positive, 12 volts+ through a fuse.
> Connection B (Black with white stripe) ignition positive, 12 volts+
> Connection C (plugged) not used (not used in factory system either)
> Connection D (Black wire) ground, 12 volts-
>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
 
Read here
http://bdub.net/gmcmotorhome.info/addens.html

Read the whole story

> Forgot to include this note:
>
> Try to use multi stranded wire as a single wire is very stiff.
>

>
> > Bob,
> > As luck would have it you can build your own connector;-)
> >
> > Napa #s
> > 725267
> > https://www.napaonline.com/napa/en/p/NW_725267/NW_725267
> > 725170
> > https://www.napaonline.com/napa/en/p/NW_725170/NW_725170
> > 725152
> > https://www.napaonline.com/napa/en/p/NW_725152/NW_725152
> >
> > http://bdub.net/gmcmotorhome.info/figs/vacpump/vac.html
> >
> > This is what you were looking for:
> >
> > Connection A (Red wire) battery positive, 12 volts+ through a fuse.
> > Connection B (Black with white stripe) ignition positive, 12 volts+
> > Connection C (plugged) not used (not used in factory system either)
> > Connection D (Black wire) ground, 12 volts-
> >
>
>
>
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
> GMC=Got More Class
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://bdub.net/gmcmotorhome.info/
Alternator Protection Cable
http://bdub.net/gmcmotorhome.info/APC.html
 
PERFECT. THANK YOU SO MUCH gentlemen. I'm on a mission that if I got it around. Get it on. Thus not getting lost, and off the shelf. Bob Dunahugh
 
These Vacuum were lasted used in the Mid 1980’s. They are still available on the models listed in the Supplemental vacuum pump list. Having search the men’s malls you have to be careful. I have found that you will have a 50/50 chance to find a working pump. The diaphragms have had a high failure rate. Remember that most are more than 30 years old.

J.R. Wright
GMC GreatLaker
Newsletter Editor/Publisher
Tech Editor
78 Buskirk 30' Stretch
75 Avion Under Reconstruction
Michigan

>
> Read here
> http://bdub.net/gmcmotorhome.info/addens.html
>
> Read the whole story
>
>

>
>> Forgot to include this note:
>>
>> Try to use multi stranded wire as a single wire is very stiff.
>>

>>
>>> Bob,
>>> As luck would have it you can build your own connector;-)
>>>
>>> Napa #s
>>> 725267
>>> https://www.napaonline.com/napa/en/p/NW_725267/NW_725267
>>> 725170
>>> https://www.napaonline.com/napa/en/p/NW_725170/NW_725170
>>> 725152
>>> https://www.napaonline.com/napa/en/p/NW_725152/NW_725152
>>>
>>> http://bdub.net/gmcmotorhome.info/figs/vacpump/vac.html
>>>
>>> This is what you were looking for:
>>>
>>> Connection A (Red wire) battery positive, 12 volts+ through a fuse.
>>> Connection B (Black with white stripe) ignition positive, 12 volts+
>>> Connection C (plugged) not used (not used in factory system either)
>>> Connection D (Black wire) ground, 12 volts-
>>>
>>
>>
>>
>> --
>> Bruce Hart
>> 1976 Palm Beach
>> Milliken, Co
>> GMC=Got More Class
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> --
> Gene Fisher -- 74-23,77PB/ore/ca
> “Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://bdub.net/gmcmotorhome.info/
> Alternator Protection Cable
> http://bdub.net/gmcmotorhome.info/APC.html
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Gotta say that's some perfect examples of great information networking including what it was used on and the Pinout.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
"I switched to the Long pump which was from a Ford electric car (Azure) but that pump is no longer available. That pump puts out a lot more vacuum.

Emery Stora"


Could you run two of the GM ones in parallel? Twice the vacuum and maybe redundancy as well?

Pete


--
Cary, NC

No Coach yet but likely center kitchen, dry side bath Royale, 78, 403, hopefully with good original white Imron paint.
 
That would help the recovery time but the extra degree of vacuum, about 3" more vacuum, gives more braking so two pumps would not give a lower vacuum than one pump

Emery Stora
77 Kingsley
Frederick, CO

>
>
>
> "I switched to the Long pump which was from a Ford electric car (Azure) but that pump is no longer available. That pump puts out a lot more vacuum.
>
> Emery Stora"
>
>
> Could you run two of the GM ones in parallel? Twice the vacuum and maybe redundancy as well?
>
> Pete
>
>
>
>
> --
> Cary, NC
>
> No Coach yet but likely center kitchen, dry side bath Royale, 78, 403, hopefully with good original white Imron paint.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
IMHO, the way to use the old GM vacuum pumps is to install them between the
engine and a vacuum reservoir (30" of 4" PVC in the rear of the #1 front
crossmember), with that reservoir supplying vacuum to the booster.

That way, the vacuum stored in the booster, and another 3 applications in
the reservoir, will begin at the highest vacuum last created by the engine
during deceleration, but never lower than what the pump is capable of
creating.

Ken H.

>
> Could you run two of the GM ones in parallel? Twice the vacuum and maybe
> redundancy as well?
>
> Pete
>
>
 
But only good for one pump.
On Sun, Feb 26, 2017 at 4:43 PM Ken Henderson
wrote:

> IMHO, the way to use the old GM vacuum pumps is to install them between the
> engine and a vacuum reservoir (30" of 4" PVC in the rear of the #1 front
> crossmember), with that reservoir supplying vacuum to the booster.
>
> That way, the vacuum stored in the booster, and another 3 applications in
> the reservoir, will begin at the highest vacuum last created by the engine
> during deceleration, but never lower than what the pump is capable of
> creating.
>
>
> Ken H.
>
>

>
> >
> > Could you run two of the GM ones in parallel? Twice the vacuum and maybe
> > redundancy as well?
> >
> > Pete
> >
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://bdub.net/gmcmotorhome.info/
Alternator Protection Cable
http://bdub.net/gmcmotorhome.info/APC.html
 
By test, my reservoir is good for three stops with no engine. Since the NO is going to hook up the power to the pump, we'll have to ask him how it
does with the pump running. I suspect it will keep you from hitting things.

--johnny

NO = New Owner
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"The road goes on forever, and the party never ends" --Robert Earl Keen