: 1975 cadillac towing vacuum

08-25-09, 04:53 PM
Question: I am not really inclined on topics about towing. I looked at the vacuum diagram for my 75 Cadillac and noticed that there is a vacuum storage tank for cars equipped with the trailer towing package.

What is the storage tank for specifically? Where would i be able to get one? I want to equip my car for towing one day as soon as i get the proper equipment....Thanks!

08-26-09, 12:47 PM
here are some pics, the tank is mounted directly between the cross braces. Any ideas? The pic in the link is larger and clearer btw..


08-26-09, 11:21 PM

Now everyone can see it.

08-27-09, 02:53 AM
I believe thats used for anti diesel. If you cant find one listed under your car, you should be able to get anyone from an older car that has the same size vacuum fittings.

08-27-09, 03:42 PM
The extra vacuum tank is just a reservoir. The main reason it is on the towing vehicles is for use under stressful engine conditions, such as driving through the mountains. If you are under heavy throttle, such as when pulling a trailer up a hill, there is little to no vacuum being produced. The reservoir is there so things such as power brakes and the climate control will still function properly when there is no vacuum being produced by the engine. This is also common to see on large pickup trucks.

08-30-09, 08:30 AM
My 99 K2500 454 Suburban has a hydraulic power brake booster, aka, Hydroboost, so there is never an issue with loss of power brakes when under heavy loads. All diesels have them too. Even my mom and dad's RV had it.

You can add, good very reliable units.

08-30-09, 09:46 AM
That small vacuum reservoir is Only there for the Climate Control. It is installed on cars with trailer packages to maintain the A.C.C. at a steady out put during periods of lower vacuum in situations such as hill climbing and accellerating etc. A reserve tank is also a good idea on cars that do not do any towing as they can loose some vacuum as well. A tank this small would not help a power brake booster very much at all.