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Discussion Starter · #1 ·
I swapped an 86 Grand Wagoneer to a 4BT, 47RH transmission, and NP241 DLD transfer case. I installed the gear driven vacuum pump from a 5.9 in front of the PS pump but I am wondering what all needs vacuum connections. I can run a line directly to the brake booster or I can do a Y to take it to the brake booster and the vacuum canister. Do I need to use that vacuum canister anymore or can I ignore it? If I need to use that vacuum canister, what else needs to get vacuum?

Thanks!
 

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Does the heater and air conditioner use vacuum for the air control doors?

I've got 70K+ miles (and 37 states) on the gear driven vacuum pump. I no longer remember how the vacuum is plumbed up - it has aftermarket HVAC (no vacuum required). I "think" I am plumbed directly to the brake booster...

I will be out in the shop later today, I will look and report back.

Russ
 

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Confirmed: The vacuum pump is directly connected to the check valve on the brake booster - and there are no other vacuum lines. This setup has never given me a problem.

NOTES:

1. I have no experience with Jeeps. I have installed aftermarket heat and air conditioning (HVAC) in the following: 1962 Volvo, 1971 & 1975 IH, 1986 Ford.

2. Vacuum operated air doors and the control switches do wear out. You might be better off starting over with an aftermarket unit

3. If you have the original HVAC in your grand waggy, it might be at the end of it's service life. If you use the original HVAC, be sure to follow the factory vacuum diagram and retain the check valves (if any) and vacuum canister.

Russ
 

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Vacuum on some vehicles is used for such things as cruise control, heater and ac controls, and of course power brakes. The canister was there to give you a safety measure in case the engine died and you needed to stop. Could serve the same purpose because if the engine should stop you'd have no vacuum. Stopping a power brake vehicle without the vacuum boost isn't any fun. I did that once when the belt on my vacuum pump broke. Really tests how strong your right leg is. That safety margin you try to keep between you and the vehicle in front of you evaporates real fast. LOL.
 

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1989 Jeep Wagoneer, 360v8, 727, stock for now,
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edit.....
what else needs to get vacuum?
Thanks!
Your heater needs vacuum to operate the vacuum motors for the vent doors.
131230
 
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Discussion Starter · #7 ·
1. I have no experience with Jeeps. I have installed aftermarket heat and air conditioning (HVAC) in the following: 1962 Volvo, 1971 & 1975 IH, 1986 Ford.
What kind of aftermarket HVAC systems have you used? I didn’t even know this existed but I’m interested in trying it.
 

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Thanks, Scout, my trouble is the vacuum pump has a ~ 1/2” port as does the booster but the heater seems to have 1/4” ports. Do they sell a T that has a couple 1/2” ports and a 1/4” to go to the canister?
 

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Thanks, Scout, my trouble is the vacuum pump has a ~ 1/2” port as does the booster but the heater seems to have 1/4” ports. Do they sell a T that has a couple 1/2” ports and a 1/4” to go to the canister?
Try a good parts store - first get the measurements of the following
1. Vacuum output diameter
2. One way valve (on the brake booster) diameter (does it match the vacuum pump diameter?)
3. Vacuum canister diameter (Vacuum hose lines come in many diameters)

Assuming (and it is just a guess) that the brake vacuum hose is 1/2", O'Reilly stocks this 1/2" tee connector. You will have to buy or make a reducer to go to the vacuum canister.


Other alternatives is to search the internet or search a junkyard that has older vehicles.

Russ
 

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What kind of aftermarket HVAC systems have you used? I didn’t even know this existed but I’m interested in trying it.
1962 Volvo PV544 - Speedway universal under-dash (AC only) - selected for the small physical size - won't do much good in your grand-waggy...

1971 IH pickup - Old Air Products - selected a firewall (inside) unit that gave me the ability to reuse the stock defroster outlets and the stock in-dash AC outlets


1975 IH Scout II - Vintage Air universal under-dash (AC only) - The heater and defroster still worked and it never had AC.

1986 Ford F150 (a 4bt conversion - link in my signature below) - The factory HVAC system was trashed (and in the way of turbo/exhaust). Vintage Air universal under-dash (Heat - defrost - AC in one box hanging under the dash).
Notes:
1. A universal box does not do any of its functions super well. The heat and defrost mode is sketchy... Mostly because my 4bt runs very cool. Go with a bigger (i.e. BTU rating) system and custom install it if you have the space (and money).
2. It was what I could afford at the time. 70K+ miles and 37 states, still running. Drove through El Centro, CA at 118 Degrees F showing on the bank temperature sign. Not cool in the truck, but, cool enough to not sweat.
3. If you live in the warmer regions, buy the biggest system (ie. BTU rating) you can fit into the space available.

Home - Vintage Air Note: Summit Racing got me my parts in 2 days

Russ
 

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Thanks, Scout, my trouble is the vacuum pump has a ~ 1/2” port as does the booster but the heater seems to have 1/4” ports. Do they sell a T that has a couple 1/2” ports and a 1/4” to go to the canister?
Search for "Pico Vacuum Line Tee Fittings", Summit Racing sell them as do others.
 
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