I'm having a hell of a time bleeding my brakes, I've done it a bunch of times on this car but this time is different. By now I think I've narrowed it down to the MC.

Note this is the original MC that came with the car, it's 17 years old by now. Trying to see if the MC is what's causing my sloppy pedal or not. There aren't any apparent external leaks as far as I can see.

I have the MC in a vise grip and did a traditional bench bleed using 2 tubes going back into the reservoir until no bubbles came out. Then I plugged up the outlets to see how much free play I have.

I can push the plunger in about 1/8" to 1/4" before it becomes hard. The first 1/8 to 1/4" of movement is quite easy to push in. When I install it on the car (still plugged up), the pedal moves 1-2" quite easily before it becomes stiff.

Is this normal? Or should I have close to zero free play in the MC? I know there's a little free play in the brake pedal but once I get past that, the MC still sinks in quite easily.

 

Pedal should not sink at all if the Master ports are plugged up solid.

 

If the pedal sinks with clogged ports you have a seal leak into the booster, which is probably full of brake fluid. Common problem on 88-95 Honda's. (The leaking, not clogged ports)

I should mention if the pedal sinks at all, you have a leak, either internal, or external, or air in the lines.

 

Thanks fellas, it was the MC. Got a new one, bench bled then plugged it up, had almost zero free play compared to the 1/4" on the old one. Brakes feel like new again.

There's no external leaks in the old MC, I'm guessing an internal seal failed. Will take apart later to find out for sure.