Brake Problem - What Am I Missing??

[Crimson Nape]

My 66 came with the Chevy disk brake conversion that was new when I got the project from the PO. I ran all new hard & flexible lines but used the old/new calipers & master cylinder. Bled with wife assistance, no brakes. Bled with a power bleeder, still no brakes. Replaced MC & calipers, bench bled MC and then bled the system with power bleeder, still no brakes. The pedal has felt the same the whole time - it goes to the floor. The brakes will stop the car; about 50' past the intersection.....

If I block off the port from the MC going to the front brakes, I get a hard pedal, so that makes me believe the issue is with the front brakes, right?. I have no leaks and now everything is new. What the heck am I missing? It is acting like it has a ton of air in the system, but I have used almost a gallon of brake fluid, so if there is still air in the system, it can't be much.

 

[SteveL]

Front calipers swapped or upside down. Bleeder screw goes on top

 

[thegreatjustino]

Knuckles ground for caliper clearance properly?

 

[Rustytruck]

the caliper and knuckle are ground for clearance on the Chevy caliper conversion. have you wife stand on the brakes while you look between the caliper and knuckle. Remember as the pads wear the caliper gets closer to the knuckle. there has to be enough gap to clear as the pads wear. the next thing to look for is the peddle rod in the master cylinder must go all the way back to relieve pressure and accept more fluid.

 

[Spaggyroe]

Just spitballing here... but have you checked the adjustment on the rear brake shoes?
If they are too far in, your peddle will go to the floor regardless of how well bled the system is.
Just a thought...

 

[Broncobowsher]

Caliper clearance and trapped air because the left caliper was put on the right side and the bleeders are not at the top of the caliper piston bore. Those are the two very VERY common issues. I've seen pros do the caliper side swap and spend half a day fighting it, until someone walks by and points it out.

 

[Crimson Nape]

The knuckles were not ground and they are definitely hitting and preventing the front pads from making contact. I didn't know that was a thing but I do now and I am off to do that right away. I would think the peddle would still be firm tho, but we'll see.

The rear brakes were a good suggestion and in fact mine were way out of adjustment. I fixed them earlier in the week and was convinced that was my problem, but it wasn't....