Vacuum Pump

[Cincinnati Guy]

Does a Vacuum pump from a 6.9 work on a 7.3?

Are there any differences between them, besides the pulleys? Can a sep and v belt pulley be swapped?

 

[itsacrazyasian]

Yup they can be. I'm running one from a 93 non turbo on my 86 6.9 in my 94 F350 that used to sport a 351 .

my first pump i put on it was a "new" Dorman that promptly failed about 1000 miles later and i ran over a stop sign in my neighborhood trying to avoid a car infront of me. (when i did the swap, i didn't swap in the low vacuum warning switch)

The next one was a new cardone thats been on there for some time thats been good.

 

[Cincinnati Guy]

Ok I just was not sure if the way they mount and the pulley shaft was the same between the two, since the 6.9 is on the opposite side and area of the motor compared to my 7.3 and also the fact of there being the v belt pulley versus the serpentine belt pulley.

see my vacuum pump is bad, I can pull the hose off on it, its pumping air and is making a very horrible sound, when You put your finer over the hose it wont hold the pressure.

Hoping the junkyard has a 6.9 or 7.3, just wanted to make sure before I buy one and it not work on my truck.

How do you oil these things?

 

[dyoung14]

Ok I just was not sure if the way they mount and the pulley shaft was the same between the two, since the 6.9 is on the opposite side and area of the motor compared to my 7.3 and also the fact of there being the v belt pulley versus the serpentine belt pulley.

see my vacuum pump is bad, I can pull the hose off on it, its pumping air and is making a very horrible sound, when You put your finer over the hose it wont hold the pressure.

Hoping the junkyard has a 6.9 or 7.3, just wanted to make sure before I buy one and it not work on my truck.

How do you oil these things?

They have a drain hole in them

 

[itsacrazyasian]

Sorry man i just checked the catalog listing for a 7.3 and my 6.9 and it shows a different vacuum pump for each one.

I could swear my vacuum pump came off a newer 7.3 i found at a yard.

 

[icanfixall]

Some vacuum pumps have threaded mounting holes and some don't. A serpentine belt vacuum pump is drilled and not threaded. Some pumps have the suction directed a differant way but they all work the same... these pumps wiil work turning either direction too. Any 6.9 pump will work on a 7.3 engine thats the Vbelt type...

 

[bullwhip]

how much vacuum should the pump pull?

 

[Cincinnati Guy]

Was able to find one off a 7.3 with V belt, instead of trying to pull the pulley and all off. What I did was remove the 4 bolts holding the vacuum pump(mushroom shaped piece) from the cam/pulley. I let the oil drain out, and refilled it with some oil. Then simply swapped out the bad vacuum pump with the new one.

The old one you can push down on the vacuum plunger and get an awful sound. After installing it on my truck I verified its getting good vacuum. Now When I hit my brakes it takes a second for me to stop. I am just hoping I need to bleed my brake system out. don't it sound like that's what it needs?

 

[MIDNIGHT RIDER]

how much vacuum should the pump pull?

A perfect vacuum is 29 inches Mercury; it is impossible to create more than that.

A healthy pump will hold between 20- to 27-inHG.

Not only is it important to create this vacuum, but it is also important for it to do so almost immediately, without taking five minutes for the vacuum to recover.

The warning label on all trailer vacuum gauges states "do not move truck/trailer until 15inHG is reached".