Brake booster check valve grommet Vacuum Leak - Stalling

[perko]

Hi everyone,
I thought i'd ask for some help tracking down a vacuum leak. My duster stalls when i put it in gear. It was intermittent but its getting more and more common. I tested for a vacuum leak with carb cleaner but didn't get anything. I unattached the brake booster vacuum line and plugged it and the idle seems to be good now. I got a new check valve and it worked for a while but i kept getting random stalls that got worse and worse. I suspect its the nature of the grommet. The hole in the booster is an inch in diameter, but all the valves i've found are smaller than this. Their solution seems to be a nesting set of grommets that I suspect leak. They appear to just sit on top of each other with the smaller diameter grommet being held in place by the vacuum. its easy to yank off though even when the engine is running. does anyone have experience with these things? am I installing them wrong? Does anyone have a good check valve source with the correct grommet? They never list the booster hole diameter on any of the sites. Thank!

 

[j_anderson]

Which year is your Duster and which booster does it have? My 72 Dart has a dual port check valve. Classic Industries sells one that looks like mine

Here's mine:

 

[Professor Fate]

Year and model. The boosters changed over the years.

 

[AJ/FormS]

The airleak at the booster grommet may not be 100% of your stalling.
What's your idle-timing?
If you run too much idle-timing, the throttle will be too far closed at idle, and the transfers will slow right down. Depending on your cam-size, the Transfers could even dry up. Then when you put it in gear the sudden load application will cause a sudden loss of airspeed past the transfers/Idle discharge ports, and thus the engine stalls.

 

[perko]

So just to follow up,
I think it was a combination of problems. The nesting grommets were leaking. I glued them together and they are good now. I adjusted the timing a little and it really like that. The hardest one to track down was a charging problem though. I was intermittently getting poor to no charging out of the alternator so I replaced it. I'm not sure what all the parts are but one of the six little bent pieces of metal you can see from the back had come apart. I think that i was sporadically getting a really weak spark or losing spark when the battery was near death and the alternator hadn't been spun up enough.

 

[AJ/FormS]

The charging system is made up of FOUR components;
The AC charging Coil,
the AC to DC convertor
the Regulator
and the battery.

The 6 little bent pieces are the diodes that make up the convertor. These are the most common trouble-makers. Well besides the brushes, and the battery connections, lol.