How can u tell if u have power or manuel brakes. I have disk in the front and drums in the rear.

 

Lift the hood and take a look at the brake master cylinder, if it is bolted directly to the firewall you don't have power brakes, if it is attached to a coffee jar sized can (the brake servo) with a vacuum hose leading to the manifold you do.
To see if it works sit in the car with the engine off and pump the brake pedal a few times. Then with your foot still pressing the brake pedal start the engine, if the servo is working you will feel the pedal go down a little further.
Some cars have a hydraulic pump that works in different way, Rolls Royce, some Citroen models and a lot of diesel powered cars have this, but most older cars have a vacuum servo as described above.
If your car has disc brakes it most likely does have power brakes as disc brakes normally require more pressure than drum brakes to operate.
Roger.

 

That must be a metric "coffee jar"...

The OP didn't specify what year/model we're talking about, but most GM cars used a power brake booster that's about the side of a pie plate (about 11" in diameter) and about 5-6" thick. It will be bolted between the firewall and the master cylinder.

With power brakes (note the gold-ish round booster at the right of the photo):



Without power brakes:

 

Isn't a jar made of glass or ceramic and a can made of metal?

 

For those of us that have 4 wheel drum, we need all the stopping power we can get :P

 

Or legs the size of tree trunks. Welcome to CO.

 

Thanks Joe & rustyroger,

I just learned something!

~Firebrand

 

Well in the olden days canning was a process and used glass jars!!! Ha your both right!

 

Go on the interstate about 80 mph and then try to stop. You will know after that.

 

What would a Limey know about coffee anyway?, couldn't think of any teapots that look like a brake booster!.
Roger.