View Full Version : Ford 7.3 Diesel Vacuum Pump Probs

12-02-2006, 04:15 PM
Anyone with a 7.3 Diesel have problems with replacement vacuum pumps?

Ours is a 1991, and the original lasted for about 12 years. We replaced it with a remanufactured NAPA one.

This will be the third year in a row that the pump has gone out. In Fall, when it starts to get cold, the pump begins to make noise. Then, after the first cold, snowy day, it goes totally.

This is very frustrating when you have to go out plowing and the light goes on and the brakes don't work right. It's an easy enough repair, except for having to have the pulley changed every time (none of them come w/pulley.).

We still get a free one every year, but I'm considering going to a different auto parts store and just spending the money on a different one, and order a pulley from Ford and having a whole spare vacuum pump ready to go.

Any ideas?

Gravel Rat
12-02-2006, 05:41 PM
The best way to deal with that and if you want to keep the truck is try find a hydroboost system from a 88-91 F-Superduty (F-450) and take all the vacuum assist brakes off and replace it with the hydroboost. What you will need is everything off the donor truck that applies to the brake system.

You will need to find a PS pump for hydroboost the pump puts out more pressure plus the housing has a return line barb.

Myself I would never go back to vacuum assisted brakes because I have had F-Superduty trucks for the last 6 years you step on the brakes and the truck actually stops.

12-03-2006, 01:35 PM
Sounds drastic, exspensive and alot of work Gravel Rat. A spare pump might be easier cause most of the time I dont have any problems. It only does it when it gets cold in early winter, then I put in a new one in and I'm fine for the rest of the winter.

Shady Brook
12-04-2006, 09:01 PM
I think I have a vacuum problem with mine. I have allot of brake travel with little stoping power. My mechanic replaced the master cylinder and said that the booster was working fine, which he said would not happen of the vacuum pump was bad. He thinks there is a problem in the antilocks, which I have never experienced working since owning the truck.

I have no use for this problematic and expensive to repair ford. I am loosing my third trans, am not building measureable oil pressure on the gauge for long periods of time. The truck stumbles perhaps due to the oil pump, if that is what it is. The twin I beam suspension is worthless causing alignment problems, tire wear and ruined frontend parts. If anything breaks near the engine it has to see a diesel tech. Everything is a 1000 dollar repair. It was great for a couple years, then everything is big bucks. Wireing harness $1000. If you need injectors....well, you could buy a couple gas engines for that price.

To me it is just not worth it. I know this was not the subject, I hope you get a resolution to your brake problem.

Good luck

12-06-2006, 03:19 PM
Shady Brook when the vacuum pump goes 1st it starts making noise then when it really goes out the brake light comes on indicating low vaccum,and the brake pedel gets high and hard like on a gas engine if the engine stalls.
A remanfactered pump is $129.00 at NAPA with a one year warranty, not to bad. The rear anti locks usualy don't cause low pedal and the ABS light will come on. Just bought a used E150 with the ABS light on my tech says not to worry its just works like before antillocks where around. And the van stops great. Our 7.3 is in a 1991 F250 4x4 and has been very good does every thing I ask it to do, plows snow great and stops on a dime even on ice (when the vaccuum pump works!). I would check the calipers maybe there frozen up, or if you plow snow the rotors could be rusty-pitted, the amount of salt they use here realy eats them up. Good Luck

Shady Brook
12-06-2006, 04:33 PM

Thanks for taking the time to give that great information, it is most helpful. I thought about the rotors, but replaced one and a caliper recently with no noticeable difference. I will check into it further.

Thanks again, and take care.