64 polara front disc brake conversion

lnt-1000

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i recently bought a 1964 dodge polara with a disc brake/ rear drum conversion the brake pedal only moves about 1/2" and is rock hard, it does stop the car ok but you really have to mash down on the pedal. I have noticed there is no proportioning valve would that be the problem ? if so any suggestions?
 

Dave6T4

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Power booster on this system? I have changed my '64 Polara over to front disc brakes using 1970-1972 B-body pin slider setup. The calipers are hung at the rear to avoid clearance problems with front sway bar. I have a Bendix dual diaphragm power brake booster and prop valve that was on donor '70 Belvedere. Everything has worked fine for 35 years.
 

lnt-1000

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Power booster on this system? I have changed my '64 Polara over to front disc brakes using 1970-1972 B-body pin slider setup. The calipers are hung at the rear to avoid clearance problems with front sway bar. I have a Bendix dual diaphragm power brake booster and prop valve that was on donor '70 Belvedere. Everything has worked fine for 35 years.
no power booster
 

MIKESPOLARA

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no power booster
You need to install a slightly smaller bore diameter on the master. The smaller the bore size, the softer the pedal and the pedal will travel farther. You need to determine what size you have now
 

VANDAN

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Did you try adjusting the M/C rod, under the dash, to correct pedal travel ? Takes a bit of trial, and error, but may work out. A 2 post lift Helps....
 

Dave6T4

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Disc brakes are not self-energizing like drum brakes are. That is, they do not help you put them on, as the rotation of the brake drum helps pull the front shoe on. I remember the first time I drove a car with disc brakes and no booster. I was surprised at how hard I had to press the brake pedal to make them work.
 

R/T Boy 67

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A lot of people use a 15/16" master with manual disc brakes. I have a 1 1/32" master on my manual system, and I love the solid feel it provides. I have a strong leg, so all is good.
 

bc3j

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A lot of people use a 15/16" master with manual disc brakes. I have a 1 1/32" master on my manual system, and I love the solid feel it provides. I have a strong leg, so all is good.
So do I. I don’t find it that hard to push. Car stops great. Stops like my Acura. Side note: I used all Mopar sourced parts. The Mopar parts work well together.
 

Ron H

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Sure sounds like there could be an issue with the pedal travel adj and yep it should have a prop valve. Does the pedal sit high or low? As posted, it would be a good idea to inspect the rod travel and pedal ratio setup. Check how far the rod enters the MC, it just might be bottoming out. Disconnecting the MC and moving it if there’s enough line movement allowing it or taking it off to measure the rod travel. Sometimes have to determine just what was done with a conversion if you didn’t do it yourself or know what was done. Another thing is how the pedal sits in home position, that is, not binding up against the brake light switch.
 

RemCharger

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And does it have a manual brake pedal or an auto one. See if the pushrod comes straight out of the back of the master, under the dash.
 
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