power or manual brakes

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macadoo1961

macadoo1961

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Hi I'm new to A-bodies so be patient if I have some silly or redundant questions. All you guys have lots more knowledge than I do so here we go: I would like to get some opinions on running manual or power brakes on my early A-body. Right now my car has power brakes with K-H four piston discs up front.I have had some guys tell me I don't need them for this size of car and besides the booster kind of takes over the cars engine bay and sits only about half/inch off of the valve cover.On the other hand a co-worker (who was a chrysler tech in the 70's at a dealership)told me you should run power brakes with discs always. I'm leaning towards ditching the power booster, if I do can I just bolt this master cylinder to my firewall? The bolt pattern looks the same.Could someone tell me if they know what booster and master this is on my car?Does this master look like it can be run as a manual system?thanks for your help and opinions.(I sure hope my picture uploads ok otherwise my last questions were silly ones!!!)

engine 002 (Small).jpg
 
Okay I'm not as dumb as I thought, my pic went through, and before anyone laughs their *** off and warns me of the dangers running the foam Eddy air filter I am working at getting that THING off my car, the only good part of it is the Bee on it!!! I am looking for a 273 Commando air filter for it, got the valve covers already!
 
I'll be perfectly honest with ya, I'm running a 71 Demon and I've got KH discs upfront with manual brakes. If I could have run power brakes I would have in an instant. With manual brakes you've got to really watch your following distance to other vehicles and pay very close attention to what's going on around you.

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demon seed said:
I'll be perfectly honest with ya, I'm running a 71 Demon and I've got KH discs upfront with manual brakes. If I could have run power brakes I would have in an instant. With manual brakes you've got to really watch your following distance to other vehicles and pay very close attention to what's going on around you.
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Thanks for the advice, this supports what my co-worker was telling me, but to be honest with you I don't find my power brakes all that different from manuals. Before getting this car(my first Mopar) I was use to G.M. power brakes which were much stronger or touchy. Actually that brings up another question, my car is running a cammed 360 L=474 D=280 on the cam, I know this will effect my brakes at idle due to lack of vacuum, but will it also change the feel of them all together?? I have checked my booster and check valve for leaks, both okay. thanks
 
Some of the other guys with 360 experience using that cam would be better to answer that question. If you're sure you haven't got leaks it could be the cam. Cam and room is why I didn't go with power.
 
a booster needs 14" vacuum minimum to operate. if you do consistent braking, even 14" is not enough, you will get a hard pedal within 4 stops. if you run a smaller bore master(15/16" or 1") you will get better pedal feel on manual brakes. I have a 360 in my 68 cuda with manual discs and can stop on a dime. if you still want a booster, you can run an extra can or an electric vacuum pump, but they add bulk to the engine bay. you will need a donor master for the pushrod and rubber retainer.
 
Thanks for that redfastback, you answered one of my unasked questions(14"vac), I have a vacuum gauge, should hook it up and see what vac its running.Does a cam of this size effect vacuum at all rpm? 360 with 474lift/280dur. I take it the master my car has now is more for power brakes and has a bore larger than 1"? thanks again any help is appreciated.
 
I'm running manual brakes with disc up front with my wagon. The problem is most likely when they changed over from the power brakes they kept the same sized master. In that case the pedal feel will be huge. The piston size is to big, you need the smaller size piston. Best to look at what size was available for your car in the parts supplier book. I have no problems with my brakes even after driving around town, or the track.
 
I switched my 68 Cuda from 9" manual drums to manual front disks / 10" rear drums. The intial bite when you apply the brakes with the drums was better (due to the self energizing design) than with the disks but after that the disks all the way.

It takes a more pedal pressure to stop the car but nothing that is unacceptable. FWIW you can improve the braking immensely by purchasing better pads than typical part store replacements.

BTW, the 73 Dart that was the doner for my disk brake swap had manual brakes.
 
Another thing is does your wife and or girl friend or girl friends :) Ever drive that car? Even if its just once in a great while you should keep the power brakes. I had some Close Calls but luckly was able to stop or swere while braking, not so luckly in staying in control or not seeing a stop sign in a 55 mph zone :sad:
 
Braking power of a vehicle is based on the surface area of the friction surfaces and hydraulic mechanism (drum width, diameter & shoe size, disc diameter & pad size, caliper piston, wheel cylinder & master cylinder area. The booster does nothing more than assist in applying the brakes. If you take the booster off a car and change nothing else the vehicle will have the same amount of stopping power but the driver will have to use more effort to apply the same amount of braking pressure. The reverse is also true, if you put a booster on a manual brake car and change nothing else the booster will only assist the driver in applying the same pressure to the brakes with less driver effort. For example my drag car has manual brakes and I can lock up the tires if I want, the booster can't do anything to help my braking if the brakes are locked.

Chuck
 
dodge freak said:
Another thing is does your wife and or girl friend or girl friends :) Ever drive that car? Even if its just once in a great while you should keep the power brakes. I had some Close Calls but luckly was able to stop or swere while braking, not so luckly in staying in control or not seeing a stop sign in a 55 mph zone :sad:
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I have had vehicles with power brakes that required as much effort on the pedal as my 68 does with manual disk brakes. I am a big proponent of power assit when it make a difference in the performance of the vehicle. For example if this discussion was on power steering verse manual I would be blowing the hron for power but in the case of power disk brakes on an A-body IMHO anyone that hasn't got the strength to safety operate the brakes probally should be driving period.

Certainly my wife has no issues with the brakes but she won't drive the car without power steering.
 
I don't know if its strength as much as what you're used to. My daily driver, when my wife isn't using it to go to work, is a 2002 Grand Prix GTP with of course 4 wheel disc's. I find that when I'm driving the Demon with manual brakes, even discs up front, I have to pay a little closer attention to my following distances. Hell I've even got 4 wheel discs on the Jimmy and I wouldn't buy a new vehicle without 4 wheel discs now.
 
Well this obviously is a matter of personal preferance, I think I'll give the manual brakes a try, no harm in giving it a shoot, I can always switch back easy enough, will have to wait for some dry wheather! I read some of the older posts on brakes, thanks for the opinions.Sorry if I got off topic on the cam questions, another thread I guess, I'm a newbie to this posting stuff! As for the wife driving the car,she doesn't drive standard and I'm not about to teach her(ha,ha this is my toy she can just close her eyes and hang on!!)
 
demon seed said:
I don't know if its strength as much as what you're used to. My daily driver, when my wife isn't using it to go to work, is a 2002 Grand Prix GTP with of course 4 wheel disc's. I find that when I'm driving the Demon with manual brakes, even discs up front, I have to pay a little closer attention to my following distances. Hell I've even got 4 wheel discs on the Jimmy and I wouldn't buy a new vehicle without 4 wheel discs now.
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I have the 68 Barracuda with manual disks, a 99 Dakota with power disk/drums and an 03 PT Cruiser with 4whl disks. I adapt to the changes in braking after the first time I step on the brakes when jumping from one to the other.
 
I have manual brakes in my DART GTS 440.

THinking of changing to manual discs with the SSBC kit.

Anoyone have experience.

Thanks

Chas
 
if you want to keep the 4" bolt circle as well as looking stock, SSBC kit is the way to go. the rotors come with 10 lugs in them, 5 with the 4" bc, and 5 with the 4.5" bolt circle. you just press out what you don't need.
 
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