Brake conversion on 65 Plymouth Belvedere

[Paul Cotton]

I have a 1965 Plymouth Belvedere that the previous owner installed power disc brakes on the front with drums on the rear. I am running a Bullet hi performance cam in a 440 ci engine. The lack of vacuum due to the cam is causing havoc with the brakes. I installed a SSBI vacuum pump and reservoir tank on the car, but I am not happy with the results. (very noisy and brakes are grabby) I am thinking about eliminating the power brake master cylinder and going with a manual brake master cylinder. What type of master cylinder will I need to buy to accommodate both the disc brakes in the front and the drums in the rear?

 

[Darter6]

The master you have should be the same Disc/Drum power or non. I am running SSBC 4 wheel manual disc brakes on my 65 Belvedere 1 for 13 years now.Stops just fine.

 

[Fran Blacker]

Not saying what wrote Darter6 is wrong.
I did the Mopar Action disc conversion they used a E77025 1" bore for master cylinder for manual brakes. The article said if you use a larger bore pedal pressure will increase. For PB they used a E75818 with a 1-1/32 bore. I'd try what you have and work from there.

 

[moes]

When I went with Disc/Drum setup a Mopar friend told me for each 1/16" increase in master cylinder bore you need 12% more leg. An increase of 1/8" in the master bore would require 25% more leg.
..stick with one inch or 15/16". So I went with a 1 inch bore. The brakes work great now, much better then Drum/Drum brakes. I used a A-1 CARDONE 101326 master cylinder made for a 1970 Duster with Disc/Drum setup. I also had to add an adjustable valve to the rear brake line so you can control rear wheel lockup. You want the front discs to come on first and then the rear drums. 80% front 20% back

 

[5.7 hemi]

15/16 is what your gonna need.......will have plenty pedal feel and will make the brakes work perfectly!

 

[Rick Carson]

15/16 is what your gonna need.......will have plenty pedal feel and will make the brakes work perfectly!

But remember to check the piston for the grove to lock in your manual brake push rod,some power brake ones don't have it

 

[Paul Cotton]

When I went with Disc/Drum setup a Mopar friend told me for each 1/16" increase in master cylinder bore you need 12% more leg. An increase of 1/8" in the master bore would require 25% more leg.
..stick with one inch or 15/16". So I went with a 1 inch bore. The brakes work great now, much better then Drum/Drum brakes. I used a A-1 CARDONE 101326 master cylinder made for a 1970 Duster with Disc/Drum setup. I also had to add an adjustable valve to the rear brake line so you can control rear wheel lockup. You want the front discs to come on first and then the rear drums. 80% front 20% back

Where did you mount the adjustable valve? Does it require adjusting very often?

 

[moes]

Where did you mount the adjustable valve? Does it require adjusting very often?

Behind the distribution block 8 or so inches. Once you have it adjusted to were you like it you are done and you do not need to adjust it again. I went to an empty parking lot, while it was raining not to hard. Started doing stops at 40 and adjusted the valve to have the back brakes come on just a bit and work from there, (you will know if the back brakes come on hard first) it will take a few times to get them adjusted the way you like them. I also seen them mounted up near the MC to. I like to put it were it is pretty well out of site and the car looks factory

 

[AMX364]

I set my adjustable valve on a daily driven car in a empty parking lot with a layer of glare ice, once set there it also worked fine on wet roads. My first valves were very much under the car about under the drivers seat. However I found the Willwood valve to be a better option, no extra connectors as all lines run to the valve.

 

[Tempest 455]

Mine is right under the dash where you can adjust it while seated.

 

[Centerline]

Installed mine beside the master cylinder just so it would be easy to adjust and I wouldn't have to crawl under the car or reach for it.

 

[Paul Cotton]

Where did you mount the adjustable valve? Does it require adjusting very often?

Behind the distribution block 8 or so inches. Once you have it adjusted to were you like it you are done and you do not need to adjust it again. I went to an empty parking lot, while it was raining not to hard. Started doing stops at 40 and adjusted the valve to have the back brakes come on just a bit and work from there, (you will know if the back brakes come on hard first) it will take a few times to get them adjusted the way you like them. I also seen them mounted up near the MC to. I like to put it were it is pretty well out of site and the car looks factory

If i may ask, what adjustable valve did you use?