Appling Brakes Engine stalls

[XBRIT]

I have an issue with my 72 Challenger 727 auto P/steering P/disk brakes now with a 383, their seems to be a vacuum problem, I can get the motor to idle but when I put it into reverse the motor stalls, but on reflection I also apply the brakes when selecting reverse, could there be a vacuum leak in the brake boster I have also noticed that when driving and braking the brakes seem to stay on for a short moment can these issues be related?
I have completely replaced the whole braking system including the proportional valve and master cylinder, but did not replace the brake booster, do you think this could be my problem?
Cheer,

[8657hemi]

Does it idle smoothly?
Could you idle just be set too low?
Any other reason there seems to be a vacuum problem?

[BB73Challenger]

When I have had a brake booster leak bad enough you should hear it no problem.
Just to be safe a thought would be to temporarily cap your vacuum for the brake booster & try to put it in gear?

[XBRIT]

When I set the Idle with the brake booster vacuum connected and then cap off the brake vacuum the engine stalls. In other words the motor wont idle at that mixture setting. What I will try is to cap off the booster and adjust the idle mixture so it runs good then put it in gear with the booster disconnected and see if it stalls.
What about the brakes momentarily dragging after being applied?

Reading thru some early booster vacuum treads some one mentioned that when he applied the brakes that the idle goes up a couple of hundred RPM but quickly recover. I am now confused if the booster leaks should it increase RPM or stall? 
Thanks for your words.
Cheers,

[72 cuda]

Possibly the vac. adv.?
Mark

[72cudamaan]

Applying the brakes should have no effect on the idle whatsoever. If it does then there is a problem. You also shouldn't have to adfjust any mixture screws if you disconnect the booster. Something is wrong here.   

[Bullitt-]

You should see no difference with booster connected or not so you apparently have issues with the booster..  Rebuilt replacements are available through most auto parts stores or if finish & quality are important send it to Booster Dewey http://boosterdeweyexchange.com/ 

[Aussie Challenger]

If idle goes up when brakes are applied then it is running too rich, does it stall when only brakes are applied or after selecting rev or drive, if it dies when putting into gear then it may just be idling too slow. When adjusting idle mixtures I always adjust to the highest idle when not using a gas analyzer and then just richen very slightly. When applying the brakes the power booster allows a slight leaning of the mixture momentarily, where have you got the power hose connected?   

[CUDA JAS]

Are you setting your idle speed (not mixture) in Drive or in Park...and what is the idle speed?

[XBRIT]

Right... I have exchanged the Torker for a new Edelbrock dual plane manifold and replaced the Edelbrock 650 CFM carb with a new one. I new valley gasket sandwiched with two new intake gaskets. Its now Okay when cold or even warm....but when at full operating temperature it goes lumpy and dyes, when I pull up at the lights. It does not seem to make any difference when I use the brake booster apart from the servo seem to stay on momentarily after a I have release the pedal.
I have not set the idle in park, but will try that when I can get to my car. I have no idea what the idle RPM's are as the rev counter seems to jump and the needle stick at 1200rpm. That will have to be taken care of next.
Thanks again.

[mojavered]

Applying the brakes should have no effect on the idle whatsoever. If it does then there is a problem. You also shouldn't have to adfjust any mixture screws if you disconnect the booster. Something is wrong here.   

Doesn't the idle need to be set a little higher in an auto car?  If it is set too low, can't that cause the car to die if the car is in drive, but stopped?
It might be a good idea to hook up an after market tach just to see what your idle is when engine is in park, cold and warmed up.   

[GoodysGotaCuda]

Pinch off the vacuum line going to the booster. (make sure there are no major leaks/cracks in that line anywhere).

Try it again, if it stalls; thats one issue
If it does not...then you have a major brake booster vacuum leak (been there; done that)

[UKcuda]

Just throwing this in - I had a fault on my '72 Mustang where the engine would stall when I put it in drive with the brakes on.

It turned out to be an ignition fault with a poor feed to the coil.  Putting it in Drive was pulling the revs down and putting the alternator below charging speed.  Using the brakes was pulling extra current through the stop lamps which was enough to stall it.

I was looking for a carburettor fault and I only found the real fault when I realised that turning on the head lamps had the same effect.  As I say, just throwing it in.