Brake Pedal Sticks to floor, brakes work

[old colonel]

After being parked for 18 months ( i was deployed) drove the 1978 911SC home from my son's garage. All was good, usual smoke from a long parked engine which quickly dissipated, it drove fine until i hit the brakes hard and the pedal stayed down with brakes engaged. I pulled over and discovered the the pedal can simply be pulled back up and brakes disengage.

It continues to do it.

Is there a return spring of some sort or is the master cylinder shot, or what?

[Albert356]

sounds to be the pedal assembly or maybe the rod going up to the master if your able to disengage by pulling the pedal back. i would start there.

[yelcab1]

First guess, brake pedal assembly at the pedal housing.
Second guess, master cylinder.
Third guess, leak in the line.

[Albert356]

I would rule out the leak because of him being able to disengage by hand. A leak would just cause the pedal to hit the floor with no engagement.

[rick-l]

Is the pedal supposed to move more than an inch?

[Albert356]

They should have like an inch to an inch and a half before you feel the piston.

[rick-l]

and then that Incompressible Fluid shouldn't let it move much more. If it is going to the floor that is a problem.

[old colonel]

Pedal actually moves about two inches then stops before the floor and does not return

It does not go to the floor

I just Went back out started the car checked and measured travel with a measuring tape

[rick-l]

return spring in the master cylinder? I s there a lot of travel like the front or rears are empty?

[old colonel]

Other thanthe failure to spring back everything else feels correct