master cyl. for pwr.disc brakes

-
J

jerry's demon

Active Member
Joined
Jul 11, 2006
Messages
38
Reaction score
0
now have manual disc brakes on 340 demon. stock motor. my m/c now has
1 sq. port & 1 rect. port. want to put pwr. brks. on. picked up a used booster
& bought a pwr. m/c at the local parts store. the new m/c has 2 sqare ports.
they claim this is what the book calls for. anyone have an orig. pwr. brake car
to confirm the right m/c i need? thanks.
jerry
 
Jerry I don't have a Demon but the M/C I used on my Cuda conversion to disc brakes was for a 73 Dart and NAPA showed the same part for both power and non power brakes and I think the M/C's were the same for most A body cars. You can go to www.napaonline.com and do a search for your self to see what comes up. They even have pictures there. Just to let you know I ran into problems with getting a good rebuilt M/C and several other guys on here posted the same problem. Some other guys also posted having problems getting different looking M/C's by the same part number. I finally went with a new one from NAPA. Only cost about $15 more too.
 
1968FormulaS340 said:
I have non-power discs and don't know why anyone would need or want to add the booster.
Click to expand...
Well actually their is a place for power brakes. I have manual disc brakes on my Cuda and have no problem with them but then again I can leg press 400 lbs. On the other hand my wife weighs 95 lbs. and has a little problem with them. She can stop them but after driving the Grand Prix all the time she's a little wary of them and if in a panic situation even though I'm confident in her driving I'm not sure she'd do so good getting it stopped in minimal distance. If only a strong legged ox like us drives the car non power is just fine but when a frail little woman gets behind the wheel the story is different.

One thing I'll say though is that I'm sure glad I don't have a booster in the way when I work on it.
 
On some cars there are different part numbers due to a slight bore diffference in the cylinders.

Some books show a change up to what looks like a drum cylinder. I have never used that one with the two ports the same, for that reason.

In any case, I have used the "manual" cylinder with a powerbooster, with no issues.

I would try that if I were you. You won't even need to bleed the brakes if you do it that way. Just set the master there with the lines still hooked up.

Important thing on the swap, is that there is no other vacuum accesory in the same line as the booster (ie pcv valve) it will cause a crappy pedal feel.
 
On a lightweight car suchas an A body, I don't understand why anyone would have power brakes.

My 1969 340 Swinger had factory power discs, which were too touchy and way over-boosted.

My 1970 340 Duster and my current car - 1971 340 Duster are both manual disc equipped cars which have a much better pedal feel, and stop as well if not better than my power brake 340 Swinger.

The booster takes up precious underhood space, requires a vacuum draw from the intake manifold, and adds weight to the car, while at the same time, adding no significant performance advantage on a lightweight A body.

Dump the booster--simplify your car.
 
hey,thanks guys for the info. one of the reasons i was going to put p/d/b on car was fender tag says it orig. had them. the man. d/b work fine. only have
one problem with them. the m/c has a slight leak on the end where the brake pedal rod
contacts the m/c. is there a seal that can be replaced without rebuilding the
whole m/c? i think, by your comments, i will just stay with my manual d/b
m/c. thanks.
jerry



2005 chrysler 300 c
 
Hi Guys,

I have a 72' Duster with standard front drum brakes. I want to replace the drum brakes with front disc brakes from a 74' Dart with power brakes. Can I just leave the power assist unit off and use the master cylinder off of the 74' Dart as a standard brake master cylinder or is the power braking system required?

Thanks,
Chris
 
You must log in or register to reply here.
-

Back
Top