89 Toyota pickup/22-re/5 speed

my brakes are acting up and was looking for ideas as what to check. when I hit my brake pedal , I may or may not have brakes at times, it just started out of the blue. I het the brake pedal and it went to the floor like a broke brake line, I can pump the brakes some and it will get a partial brake. today once the brakes were perfect and the next pump went to the floor ?

ighway

 

Master cylinder is prolly bad

 

I had similar issues and would suspect the master cylinder as well.

 

Your losing pressure in your brake hydraulics at some point in the system. Could be a bad Master but at some point the sealed system is compromised. Follow all brake lines from the Master cylinder down to calipers and drums. If it's not your master cylinder you'll find brake fluid leaking at some point. I had a ruptured seal on a caliper piston once that caused my pedal to hit the floor and brake fluid to puddle up under the caliper.