Troubleshooting brake system

[Matt B #26021]

Hello,
I have a 65 deville and the brakes are non-operational at the moment. I do not have a ton of experience with brake systems so I thought that I would ask here before my trial and error.

The car has newer brake lines. The master cylinder is full of fluid. When the pedal is pressed the brakes do not stop stop/slow down the car.

What should I check first? Then next?

[Otto Skorzeny]

Get all 4 wheels off the ground at the same time and have someone check each one to see if it can be turned when you press the pedal. Do they drag at all? Is there no change? Do some stop and others not stop?

Check each wheel cylinder and shoe / drum. Maybe they're all way out of adjustment and the shoes aren't making contact with the drums? (probably not but I don't know the car's history)

Can you see any movement at all in the shoes with the drums removed? If nothing at all is happening anywhere then you should replace the master cylinder.

Bear in mind I am assuming that the lines are all free and clear with no corrosion or leaks or anything else obvious.

Can you move the wheel cylinder pistons in and out freely by hand without binding or anything? If not, they should all be replaced.

What do the rubber hoses look like at each wheel? If they show any signs of age/cracking, flaking, etc. they should be replaced. They could still look good and be collapsing inside but check the obvious stuff first.

What sort of action do you get from the booster? An easy test for the booster is to pump the pedal until it gets hard with the car turned off. Keeping your foot pressed on the now-hard pedal turn on the car. Your foot should instantly push the pedal another couple of inches as soon as the car starts if the booster is working.

[35-709]

When the pedal is pressed does it go to the floor or is it hard (engine running)?  If it is hard I would suspect the power booster, there could be either a vacuum leak, a collapsed vacuum hose to the booster (been there), or the booster itself needs to be rebuilt/replaced.  If it goes to the floor, I would suspect the master cylinder --- possibly the brakes need to be bled but there would be a reason for that.  Do you have a friend that is familiar with brake systems that can be there with you to help?  I would certainly lean on him for advice, brakes are not particularly difficult but for a novice you really need someone to guide you.  One thing you need with that car is good, RELIABLE brakes.
Geoff N. 

[Gergely Szentmartony 25603]

Matt,
I know you won't like my answer but I cannot resist writing it down specifically on your account.

If you really "do not have a ton of experience with brake systems" - as you said - then you should turn to an expert.

I have been a technical trainer of dealers' technicians for more than 20 years now and I have always started my brake and steering courses with the following two sentences:
"You should never forget. Never play with the brake, the steering and the grizzly bear!"

[Carfreak]

Some very good reading includes sections on Principles of Operation, Troubleshooting, Servicing, Bleeding, Testing: 

http://www.modifiedcadillac.org/documents/Multiple_Years/1964-77%20Power%20Brake/

http://www.modifiedcadillac.org/documents/Multiple_Years/Drum%20Brake%20Service/

[Dave Shepherd]

Agreed, I wanted to say this also but many would be insulted.

[Matt B #26021]

Great advice everyone. Ill update this thread when a solution is found.

Gergely point well taken