Have a car with factory 73-up disks up front and drums out back. Have a Wilwood 1" master cylinder. Brakes are soft and want to frim them up. Should I go to a .94 or a 1.12 bore?
Many thanks.
Many thanks.
Master bore size
- Thread starter moparmarks
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I use the smaller bore.
I do not have enough foot strength
anymore to effectively stop with the larger bore!
I do not have enough foot strength
anymore to effectively stop with the larger bore!
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1WildRT
Well-Known Member
What do you mean by "soft" if you mean spongy that describes air in the system... Bleed the system...
If you would like it to require pushing harder to cause the brakes to be effective use a larger bore M/C
If you would like it to require less pedal effort to cause the brakes to be effective use a smaller bore M/C
If you would like it to require pushing harder to cause the brakes to be effective use a larger bore M/C
If you would like it to require less pedal effort to cause the brakes to be effective use a smaller bore M/C
Kendog 170
Let the boy go !
I have the larger bore in my Ragtop. I can't lock them up the petal is so hard. Hopefully this winter I'll put in the 15/16th inch bore master.
Im fairly sure OEM for 73 poeer disc-drum was 1.125 bore.
Power anything and everything was designed to put more ladies in drivers seats and second cars (station wagons) in driveways. Chrysler was king of easy.
Automatic transmissions and one could hardly feel a gear change.
Power steering, steer them with a pinky finger. Mushy soft brake pedals.
A owner changes from dad's hard *** manual drum pedal to lady brakes and "WTF is wrong?" Answer is probably nothing. Nature of the beast. You can take them back to the manly side with changes. "Pump it down" articles address the steering effort. Shift kits make harder gear changes. Different master bore and/or delete the booster for different braking effort.
Power anything and everything was designed to put more ladies in drivers seats and second cars (station wagons) in driveways. Chrysler was king of easy.
Automatic transmissions and one could hardly feel a gear change.
Power steering, steer them with a pinky finger. Mushy soft brake pedals.
A owner changes from dad's hard *** manual drum pedal to lady brakes and "WTF is wrong?" Answer is probably nothing. Nature of the beast. You can take them back to the manly side with changes. "Pump it down" articles address the steering effort. Shift kits make harder gear changes. Different master bore and/or delete the booster for different braking effort.
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Inertia
Well-Known Member
Here's M/C specs .
Inertia
Well-Known Member
I recently had the owner of a 67 Barracuda bring the car back, even tho he had had the brakes done previously, he just wasn't happy with the brakes, adding he wasn't really happy with the brakes since purchased, new brakes didn't seem any better.
Drive it and Confirmed the brakes weren't "great", but 9" drums ?
I took the 9" drums off, the wear on the shoes and drums was near total contact.
My immediate thought was the Master had been changed thru the decades, and probably had a larger bore M/C installed for whatever reason.
Removed it, - Nope, was the 1" bore it was supposed to be. hmmmmm
I stock the 15/16 bore M/C, so thought what the hell.
It's a disk m/c with a large reservoir, - makes no difference, yeah, I know, yada yada. .
Well. Hot damn.
The difference of 1/16 smaller bore made all the difference, locks up, nice feeling, hard pedal.
Some will recognize this car, -
So I explained that at shows and such, someone will notice the disc m/c and ask about the disc brakes, which would lead to why the WRONG m/c, and - YOU CAN'T DO THAT ! !
I suggested he just nod his head and smile, knowing he has the best brakes ever .
Customer is super happy !
Pics of removed m/c measured .
Drive it and Confirmed the brakes weren't "great", but 9" drums ?
I took the 9" drums off, the wear on the shoes and drums was near total contact.
My immediate thought was the Master had been changed thru the decades, and probably had a larger bore M/C installed for whatever reason.
Removed it, - Nope, was the 1" bore it was supposed to be. hmmmmm
I stock the 15/16 bore M/C, so thought what the hell.
It's a disk m/c with a large reservoir, - makes no difference, yeah, I know, yada yada. .
Well. Hot damn.
The difference of 1/16 smaller bore made all the difference, locks up, nice feeling, hard pedal.
Some will recognize this car, -
So I explained that at shows and such, someone will notice the disc m/c and ask about the disc brakes, which would lead to why the WRONG m/c, and - YOU CAN'T DO THAT ! !
I suggested he just nod his head and smile, knowing he has the best brakes ever .
Customer is super happy !
Pics of removed m/c measured .
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The above table contradicts my experience, and other information sources I have seen.
65-72 A-body master cylinders for manual discs used a 1-1/32 bore, for example.
The title of the second table does not inspire confidence — what is the word "Wheel" doing in this title? Are we talking about drum brake wheel cylinders, or master cylinders?
What is the source of these tables?
Inertia
Well-Known Member
1WildRT
Well-Known Member
If you take another look it says 4 wheel drum brake master cylinders...
where as the other chart states front disc master cylinders...
The articles were written by a long time forum member as well as long term Mopar Musclecar owner who's also been an engineer working for Bendix Brakes for many years.... Pretty sure Brad has done his research...
Thanks for all the replies everyone. I should have known the answer to this but, you know, getting older.
Everything is new and the rear drums are adjusted correctly. No air in system. Brakes work just want a firmer petal. Need to stay with the Mopar flange Wilwood master for this car so I'll try the 0.94 bore. Yes, a 1/16" makes a big difference.
Everything is new and the rear drums are adjusted correctly. No air in system. Brakes work just want a firmer petal. Need to stay with the Mopar flange Wilwood master for this car so I'll try the 0.94 bore. Yes, a 1/16" makes a big difference.
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Kendog 170
Let the boy go !
That looks sweet!
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