Compatibility between power and manual disc/drum master cylinders

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MADMarc

MADMarc

Just a d00d
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Alright, I'm having a hell of a time finding the correct rebuilt MC for my car. It has KH power front discs and rear drums. I can't find the correct MC at local parts stores, and am on my second one from rock auto. The first they sent me was manual drum/drum and the one I just received is manual disc/drum. Will this work on my power brake disc/drum setup? Any other recommendations for a better MC to avoid this hassle?

Any help is appreciated. Thanks all!

Ohhh, and here's a shot of the MC I have:
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...and this is the one I received:
getimage.php
 
Yea, I am concerned with the structural changes between the two. And sorry I forgot to mention that it's a 70 swinger
 
MADMarc said:
Yea, I am concerned with the structural changes between the two. And sorry I forgot to mention that it's a 70 swinger
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I got mine at Oreilly's and it was correct. They are remanufactured and the manual brake one is on the right below.

View attachment oiuytrewqwedrfghgfds.JPG


I personally like remanufactured American parts rather than new import parts. I actually got lucky and got a real Mopar casting.
 
What is the difference between the manual disk and the power disk master cylinder? I thought they were the same.
 
Oklacarcollecto said:
Bore depth for the push rod.
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From 67 to 72, the bore diameter was different between power and manual, but not in the way you'd think was logical.

The manual brakes had a larger bore, which made for more pedal effort (1-1/16 or 1-1/32", I forget which). The power brakes came with a smaller bore, making for less pedal effort (15/16").

The problem with buying an MC today is that they don't necessarily list the bore diameter. And many sources don't even list a part for all applications (for example, 67 Barracuda disc, power or manual), even when they stock the identical part under other applications. It is generally recommended to get the 15/16" bore regardless -- this makes the pedal effort on manual brakes more in line with modern expectations.

All of these master cylinders (manual, power, disc, drum, A, B) are physically interchangeable (same 4 bolt pattern), but as he said, the pushrod will be different for power or manual, and there are at least 4 different bore sizes when you add in B-bodies.

The critical difference is between disc and drum. The disc MCs always have one chamber larger than the other, and the factory ones always have the wire bale closure. Drum MCs have 2 equal chambers, and many of them have a bolt-down lid.
 
Thanks for the responses! That told me just what I needed. I will send this one back and tell them Noooo even though the guy told me yes. I'm on a waiting list at the local OReilly but will order one online and see if that helps.
 
You might want to look at this one as well. All new part not a reman, available at Summit.


http://www.summitracing.com/parts/agb-mc36283/overview/

Part Number:MC36283
Brand Name:Raybestos
Part Description:Brake Master Cylinder
Bore Diameter:1 1/8"
Number of Outlets:2
Primary Outlet Thread:(1) 9/16-20
Secondary Outlet Thread:(1) 1/2-20
Packaged Weight:8.37"
Packaged Length:11.00"
Packaged Height:5.25"
Packaged Width:7.37"
Grade Description:Premium
 
Deng! Fixed calipers here. According to the earlier post, if 15/16" is factory and manual MC's had 1 1/16-1/32" for more pedal effort, can that be simply translated to meaning it will just provide a stiffer pedal?
 
Both Cardone master cylinders fro Oreilly's show to be 1" and that is in line with the information posted above on the fixed calipers. Was 15/16" on the KH brakes or the 73 up single piston caliper? I use remanufactured Cardone on all my brake applications and haven't had an issue yet.
 
mvh said:
From 67 to 72, the bore diameter was different between power and manual, but not in the way you'd think was logical.

The manual brakes had a larger bore, which made for more pedal effort (1-1/16 or 1-1/32", I forget which). The power brakes came with a smaller bore, making for less pedal effort (15/16").
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The "pedal effort" part is not true. You are not accounting for the lever ratio in the stand-off brackets of the power brakes.

>1"D bore sounds too much for manual brakes. I recall that my 65 Dart had a 1"D bore for either manual or power brakes, but check rockauto.

I have never seen a rebuilt manual MC that did not come with the pushrod and dust bellows already installed.

I suspect that a manual MC would work for power brakes. You might need to adjust the tip of your booster output rod to match the piston (should do anyway), assuming yours has an adjustable rod (some do).

You could probably use a power MC with manual brakes, but most don't have an internal groove to capture the rubber bushing on your brake rod. I don't know that it needs to be secured. I will use a power MC (from 90's Mopar) as a manual MC on my 64 Valiant. The rod length comes out correct. I posted photos showing that a few months ago.
 
Oklacarcollecto said:
Both Cardone master cylinders fro Oreilly's show to be 1" and that is in line with the information posted above on the fixed calipers. Was 15/16" on the KH brakes or the 73 up single piston caliper? I use remanufactured Cardone on all my brake applications and haven't had an issue yet.
Click to expand...

I had also thought 15/16 was KH manual brakes, thats what I installed on my 70 Dart with KH manual
 
BillGrissom said:
The "pedal effort" part is not true. You are not accounting for the lever ratio in the stand-off brackets of the power brakes.

>1"D bore sounds too much for manual brakes. I recall that my 65 Dart had a 1"D bore for either manual or power brakes, but check rockauto.

I have never seen a rebuilt manual MC that did not come with the pushrod and dust bellows already installed.

I suspect that a manual MC would work for power brakes. You might need to adjust the tip of your booster output rod to match the piston (should do anyway), assuming yours has an adjustable rod (some do).

You could probably use a power MC with manual brakes, but most don't have an internal groove to capture the rubber bushing on your brake rod. I don't know that it needs to be secured. I will use a power MC (from 90's Mopar) as a manual MC on my 64 Valiant. The rod length comes out correct. I posted photos showing that a few months ago.
Click to expand...

I got one from Rock Auto that was a Bendix with all the stuff in a separate plastic bag
 
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