Thread: Hot Rod braking problems

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Provided the brakes are in good mechanical shape, it sounds like low line pressure. Could be too large of a master cylinder bore or not enough leverage in the pedal or both.

If I recall right, the original MII master was 7/8" bore. You need to shoot for at least 1000 psi with a leg effort around 100 lbs. Disc brakes require a lot of pressure.

Here's a couple of online calculators that will help.

https://www.markwilliams.com/calculators.html

https://techtalk.mpbrakes.com/how-to...ng-pedal-ratio

You could also have a mechanical issue. Stuck caliper pistons, stuck floating caliper (would only apply to the fronts), badly glazed rotors/pads, wrong pad material would be few possibilities.

Edit: I was close on the MII MC bore. It's actually .937". 7/8 is .875.