Master Cylinder for 66 Formula S

[dschem]

Just a question for clarification.

I have a 1966 Formula S with the stock disc brakes and the original single master cylinder. I want to change to a dual master cylinder and through my searching found

Cardone 10-3126M as being one that works with front discs and manual brakes. it says this was for 1967 Darts.

Just seeing if anyone could agree or disagree with this assessment.

I know about the adjustable proportioning valve and running the brake lines, just wondering if this master cylinder would work.

Thanks

Dave

 

[wjajr]

I believe one can use any manual disk/drum MC four stud mount from later cars such as A body, and F body. The newer MC’s have larger bowls, and a choice of bore size. I installed Raybestos 36412 with 1 1/32” bore which works well with four piston KH front disks on my 1967 Dart. Later model single disk stile calipers may work easer with smaller bore MC. It has to do with the ratio between MC piston area to Caliper piston area as to how easy pedal feels.

If you have 10 inch rear drums, consider installing smaller diameter wheel cylinder than factory used to lessen premature rear wheel lock up such as Napa 37676 or Raybestos 37696. Back in the day factory fitted cop cars with these smaller cylinders to keep them from doing 180* spins during hard braking.

You can read more about MC & wheel cylinder choices to use for converting from single pot to duel pot at that other site “slantsix dot org” authored by slantsixdan using “Search” function.

 

[cosgig]

I have the exact same setup on my 66 Cuda, and did the conversion myself. Heres what I did...

I used a complete disc brake setup from a 67 Cuda and ordered a complete new brake line set for that is correct for 66 disc brake cars. You may only need the MC pieces to do the conversion, but thought I'd mention it. Everything from the 67 bolted directly in to the factory 66 locations. When it came to the MC, I used a manual disc MC that is correct for a 1969 Dart with manual disc, and it bolted directly in, and the MC lines did also. It was a complete bolt in, no fabbing of any kind, just the way I like it!!

I know there are probably upgrades in the MC you can use, but the above is what I did, and it stops just fine!! The 69 MC I used and the one you found for 67 may be the same unit, but I'd check just in case before buying. Good luck with your project, Geof

 

[wjajr]

My 67 Dart came from the factory with optional KH disk brakes; all I did was upgrade the small sized ‘67 factory master cylinder. As Cosgig said it is all bolt up parts, however I bent my own tubing for the rebuild copying the factory bends. I would spend a few extra bucks and only use a new not remanufactured master cylinder.

This is a very good project to make your car safer, more reliable, and dose not cost any more than if you were to replace the original single pot.

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[dschem]

Hello,

Thanks for the info.

Do you know what bore size you had? Mine is 1 inch and I am looking at keeping that as the newer master cylinders do not come with the rod.

Dave

 

[dschem]

Hello,

Thanks that does look nice and I am all for the added safety. Mine will be a little tighter in there because of my 273 along with the Dougs headers I have. I will be bending my tubing new also. I am going to use an adjustable proportioning valve for the back brakes.

Dave

 

[wjajr]

There is plenty of room with a 273 to install the larger master cylinder. Remember the later cars also had small blocks mounted under the later sized mastercylinders.

Go onto Rock Auto and shop for bore size in a manual disk/drum master cylinder from 72 through mid-80’s A & F bodies. I think all rod lengths for manual disk/drum are the same. Just a smaller bore will give you more pedal travel compared to larger bore. It has to do with volume of fluid each size bore & stroke delivers to slave pistons in caliper. Small bore will deliver less volume per full stoke then a larger bore when connected to same slave. More foot travel equates to less foot force to exert same braking force to disk compared to larger bore MC.

 

[dschem]

Hey,

Thanks for the info.

So the rod I have, original from the 66 with a 1 inch bore, will work with any of the bore sizes?

Dave