66 barracuda - converted to dual master cly, could stock pushrod be too short?

[66fyssh]

I just did the upgrade to a dual master cylinder on a 66 Barracuda, manual brakes with factory from Kelsey Hayes disc. I used a new master cylinder for a 73. Kept the original proportioning valve that I just rebuilt.

Bench bled the master cylinder, all lines are tight, no leaks. Bled all four corners.

Now the brake pedal starts lower than original. So low it doesn't even touch the brake light switch. And when fully depressed, it feels like its very close to the floor. I didn't think I needed to change out to push rod, but maybe I do? The stock pushrod is not adjustable.

Does anyone have any suggestions? Is there a certain year pushrod that will help?

Thanks!!!!

 

[66fyssh]

OK, so I see that Doctor Diff has an adjustable master cylinder push rod for A-bodies. I don't see any other reason it's not lining up so I'm putting one order.

 

[BillGrissom]

Manual brake MC's usually come with a push-rod & dust-boot. Most likely your new MC was intended for power brakes. But, that probably doesn't explain it. More likely, the later dual reservoir MC has a deeper rod hole in the piston. Having to adjust the brake switch is a given. As long as the MC bottoms out before the pedal hits the floor (test it dry), that is all you need. I put an MC from a 95-99 Breeze on my 64 Valiant as a manual MC, and the pedal wound up in about the same place, even w/ a 2-4 bolt adapter plate moving the MC fwd slightly (photos in my post). I was just lucky.

 

[66fyssh]

Thanks Bill. I checked it again and the m/c bottoms out but it's a little to close to the floor for my comfort. I think you nailed it that the rod hole in the new m/c is deeper.

I ordered the adjustable push rod from Doctor Diff. Didn't want to spend the extra dollars but I figure the extra comfort is worth a little!!

Thanks again!