I have posted this same issue on the 33 Hot Rod Facebook page. I am hoping I can get some more suggestions here.

Anyway, to the issue. The brakes are down right dangerous, I can not lock them up even with two feet on the pedal. I have driven my 68 Barracuda with manual disk brakes for almost 20 years so I know what to expect in the way of effort required. They certainly take more effort than the manual drums the car originally had but they never felt inadequate and would easily lock up. The Hot Rod brakes will slow the car gradually but if there was ever a panic situation I would not be able to stop. Hence my driving has been limited to the neighborhood.

What I have for brakes on the hot rod are the Mustang GT dual piston calipers as supplied by FFR. The master cylinders are 3/4" bore Wilwood that were supplied with the kit. The rear calipers are single piston Mustang units with solid rotors I sourced for a 94 Mustang GT. The pads were generic ceramic items.

I initially set up the master cylinders with the bias bar centered and the push rods adjusted to the same length. My initial bleeding of the system was with a vacuum bleeder. I pulled fluid through each caliper until I saw no air. I then followed Wilwoods procedure and did the right front/right rear then the left front/left rear. I saw no additional air bubbles.

The first time I backed out of the garage the brakes would barely stop the car at walking speeds. I lengthened the front mc push rod and adjusted the bias bar more to the front. This made a slight improvement but driving in the neighborhood I needed engine braking to slow the car.

Here are the suggestions from the Facebook forum that I have done. Each of these have made an incremental improvement that I can now comfortably drive in the neighborhood but still can't lock the brakes at anything over 15 or so mph. Engine braking is still much more effective at slowing the car than the brakes. Also, the parking brake can lock up the rear calipers.

1. I replaced the ceramic pads with semi metallic Raybestos brand.
2. Pressure bleed the brakes. I got no air doing this.
3. Reverse bleed the brakes. I initially got a few bubbles in the reservoir with each caliper but several more ounces of fluid did not produce more bubbles.
4. Add more bias to the front brakes.

It was suggested that I swap to 5/8" master cylinders to increase pressure at the calipers. I have not done this yet. I stopped by FFR and asked them and was told that they used to supply 5/8" mc but switched to 3/4" because the smaller bore wouldn't move enough fluid under all conditions. While at FFR I tried the brakes on cars in the showroom with both Mustang calipers and Wilwood calipers. The pedals all felt very hard compared to mine suggesting I still have air in my system.

Any additional suggestions will be very much appreciated.

Dave