bw71mach1

I was taking my car to the paint shop. I stopped to get gas went about 1/2 mileand the car started to slow down. I pulled off the road and the brake pedal was really hard. When I pressed the pedalyou could hear a difference in the engines rpms. I got a trailer to get the car to the paint shop and the brakes seemed to be fine.

Any ideas of whatmight cause this.
Background:
71' Mach 1 w/ front disc brakes
New master cylinder and front pads

Sean W.

im thinking there is air in the brake line... or lack of brake fluid

try bleeding the system.

Maybe while you are at it replace the brake fluid all together.

67 evil eleanor

Do you have power brakes? If so, do you have a vacuum hose loose or a leak?

Oxnard Montalvo

A frozen caliper will give a hard pedal with little braking, but the car should pull to one side.
Maybe they're both frozen. Sometimes new pads on iffy calipers can act funny. The pistons get pushed back into the caliper bore and get hung up due to corrosion being present on the pistons. This corrosion was developed outside the bore when the piston was extended, with the new pads it's now pushed back in. A hard pedal and fluid leaks usually accompany this problem.