72 Lincoln Brake Problem

Hello all! I'm writing about an issue I'm having with the brakes on my 72 Mark IV. Here's my problem...the brake pedal has way too much travel. I've replaced the master cylinder, rear shoes and hardware and checked to ensure that the front calipers are sliding as they should. All that done, and I still have a pedal that goes almost to the floor. The car stops, but there's no such thing as a panic stop! The brake booster is good and I'm almost certain that there's no air in the lines as the brakes have been professionally bled.

A mechanic friend said that the Sure-Trac system could be part of the problem but I've been unable to locate any sort of service information about the system. It's not mentioned in my 1972 Ford/Lincoln service manual that covers the brakes. As a result, I have no way to test that part of the system. So, I'm turning to this community in hopes that someone can point me in a new direction. The car runs great and doesn't have alot of miles on it so I'd like to get the brakes up as they should be so that I can drive the yacht!

I think the key word here is "Replaced the master cylinder". Usually there is an adjustment procedure that sets the distance the position the mechanical pedal action push rod begins to exert force on the master cylinder piston. There is a prescribed position the master cylinder piston must retract to when the pedal is released to allow line pressure to return to normal.

Check your service manual about this alignment, sometimes it is done on a bench before installation on the vehicle.

It does have the earmarks of air in the system, was the master cylinder bench bled before installation? Pre filling and bleeding each master cylinder chamber (install temporary return line from outlet to the related bowl) is the best way to limit inducing air into the lines when installing a new master cylinder. There are a lot of high and low spots in the fluid lines that can trap air pockets that may need to be power bled with professional brake bleed equipment. Stude8