power brake booster questions

[dusterbd13]

getting ready to do my power brake conversion on my 70 duster. couple of quick questions.

1. at idle, i have anywhere from 11-15 in of vacuum. it isn't stable, but i believe that that was due to my testing equipment. using my mityvac as a gauge, and the manifold vacuum port on the front of my edelbrock carb. the other is timed, and at just off idle reads 15-17. should i pull the plug on the back of the base of the carb and test again with the distributor vacuum advance working, or is this accurate enough? also, will this be enough vacuum to operate my brakes correctly?

2. is there any way to test my booster on the bench before i restore it to make sure its still good? my mityvac just doesn't pull enough vacuum.

3. there's two ports on the check valve. the bigger goes manifold, but where does the little one go?

4. would it be OK to run this setup without the brace to the fender? i really don't want to drill holes if i don't have to.

5. the manual brake cars and the power brake cars used the same pedal, right?

thanks
Michael

 

[mtandrews]

1. you're cutting it close, 17-18 is the target
2. good question
3. don't know, mine only has one port
4. brace keeps firewall from flexing
5. yes

maybe someone else here that's smarter than I (that aint sayin' much) will help some.

 

[dusterbd13]

figured out a way to test my booster, and tried it tonight.

hooked a long hose up to the power brake bung on the intake of my truck. hooked other end to the larger of the 2 ports on the check valve. (by the way, this is after i removed the master to check for rod operation, and lighten the assembly up a bit.)

off the smaller, i hooked my mityvac to get a reading. reading at idle of truck, no mopar booster, 17in. with booster, 16 in. ( i think that my hoses were leaking a little air in. they're all pretty old, but i had them)

i then operated the pedal side of the booster a bunch of times. with pedal depressed, the push rod goes out quickly. vacuum reading dropped to zero while depressing, but came back at the bottom of travel. push rod returned quickly. also did the starting fluid inside the booster on the master cyl. side to see if the idle changed. no change.

so i think the booster is good. anyone want to confirm me on that?