Master Cylinder Autopsy
This rebuilt master cylinder was installed more than ten years ago (photo #1). Recently, I found it empty and the brake pedal going all the way to the floor (the '65 Valiant Signet convertible it belongs to had been parked and not driven for a long, long time).
On the end of the piston (just above to where the screwdriver is "pointing" in photo #3) there was a small, dark glob of some kind of muddy substance. Inside the master cylinder bore at about the same place, the bore is now pitted.
According to the '65 FSM (blow-up diagram on page 5-9), a washer is to be used between the end of the piston and the primary cup (the primary cup is placed on the right side of the spring in the photo). I did not find this washer upon dis-assembly of the previously rebuilt master cylinder, I don't know what purpose it would serve, and I don't know if it being left out contributed or not to the failure of the master cylinder.
This rebuilt master cylinder was installed more than ten years ago (photo #1). Recently, I found it empty and the brake pedal going all the way to the floor (the '65 Valiant Signet convertible it belongs to had been parked and not driven for a long, long time).
On the end of the piston (just above to where the screwdriver is "pointing" in photo #3) there was a small, dark glob of some kind of muddy substance. Inside the master cylinder bore at about the same place, the bore is now pitted.
According to the '65 FSM (blow-up diagram on page 5-9), a washer is to be used between the end of the piston and the primary cup (the primary cup is placed on the right side of the spring in the photo). I did not find this washer upon dis-assembly of the previously rebuilt master cylinder, I don't know what purpose it would serve, and I don't know if it being left out contributed or not to the failure of the master cylinder.
