1962 brake booster suddenly stopped working

[Rob C]

I was driving my 1962 convertible the other day. driving was fine, and power brakes worked normally. I felt no fading or progressive hard pedal. Then as i turned in my drive the brakes failed all of a sudden. Need super hard pressure to stop the car from slow speed in the drive. Brake fluid was pretty much full.
Just had a new top installed the day before but other the that no recent service.
I am thinking ( hoping) it lost vacuum or something simple. The booster may be 10 year old but the car sat for years so almost no miles on it.
What should I look for ? Thanks

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[74 Harley]

Check your vacuum lines.

 

[Jim simone]

First check you vacuum at brake booster put you finger on end of line going into booster if you have vacuume check then check valve see if it works correct if so when you start car with everything connected listen for a vacuum leak if you hear a vacume leak you have a bad booster

 

[Rob C]

Thanks for the help.
I first detached the vacuum hose at the valve and checked it...It had good suction. I don't have a vac gauge.
Next I looked in the valve (see below) and there is nothing in there. Is that the way it is supposed to look?
Also I see that the hose coming off the second port on the valve just hangs down and just sucks air. Is that right. I plugged that hose and it slowed the idle a bit but it did not improve the brakes.

The above must all be right since the booster was working just a day ago. I listened and did not heard any leaking air.
Anything else I should check?

 

[74 Harley]

So start the car and and unplug the hose off the booster. Does the engine run any different?
Plug hose with your thumb, now how does it sound? You could also have a vacuum leak somewhere else that can effect your brakes.
No vacuum,no boost.
Is the trans shifting properly?

 

[Rob C]

Okay. I started the engine. Runs fine. Pulled off the vacuum line to booster and the engine idle speed up a bit. Covered the end of the hose and idle slowed down. Pulled the vacuum line to the trans and the same thing occurred. I put a vacuum gauge on the vacuum line and it read green zone 50lbs.
I hooked it all back up and sprayed starting fluid at the base of carburetor. There was just a very small increase in idle speed. Maybe vapors floating into carb.
Does that say it is just a sudden failure of booster do you think?

 

[74 Harley]

The booster is just a rubber diaphragm, when they go, they go.