Please post any symptoms of a failing master cylinder. I am concerned that I don't have adequate braking power and I believe I may have a master cylinder problem. Based on your input, I'll decide whether to purchase and replace this part. Thanks!

 

Pedal depth feels variable and mushy.
Later, pedal goes to floor.
Later, stranded.

 

The F-150 hydraulic brake system consists, more or less, of:

• Master cylinder
• RABS (Rear ABS)
• Brake proportioning valve (so the rear doesn't lock up immediately)
• Brake lines
• Brake hoses
• Brake calipers
• Wheel cylinders

A leak anywhere in the hydraulic system will give symptoms similar to a bad master cylinder. You'll find more info on google than we could compile here. What problems are you having?

 

Limited or reduced stopping power--no where near that nose-dive feeling on a hard stop. No quick-acting power assist--more like old-fashioned hydraulic brakes where your leg muscle is all important. A sense that I need to push the brake pedal further to the floor that my other cars. Once stopped, I can push the pedal further and further towards the floor, but it never goes all the way. Truck is a 1997 2WD 5.4L 80K miles 6600 pound package with rear drum brakes; maybe 10K miles on new ceramix pads, turned rotors.

 

Might be a booster prob also. Check this by pressing on the pedal with engine off. start truck and see if your pedal goes lower. as mentioned before there is no definative set of symptoms of master cylinder failure. You might check so external signs like fluid running down the front of the booster where cyl mounts. ABS makes it a little tougher to spot problems too.