Helpful tip for diagnosing soft / spongey brake pedal:

Helpful tip for diagnosing soft / spongey brake pedal:

If you don't know where your issue is for a soft/spongey pedal, start by using vice grips on all 4 corners to pinch off the rubber brake lines to the calipers. If the pedal becomes solid, you know the issue is on the caliper side. Then remove the vice grips one at a time, testing the pedal after each one, and your the location of your issues should be pretty easy to determine. 

i suggest a minor deviation:  split a short length of fuel hose and wrap that around the vehicle's brake hose before you vise grip it.  avoids potential gouges to the brake hose's protective outer layer.

AngryCorvair said:

i suggest a minor deviation:  split a short length of fuel hose and wrap that around the vehicle's brake hose before you vise grip it.  avoids potential gouges to the brake hose's protective outer layer.

Very true, you want to be cautious not to damage your rubber lines. 

AWSX1686 said:

Helpful tip for diagnosing soft / spongey brake pedal:

If you don't know where your issue is for a soft/spongey pedal, start by using vice grips on all 4 corners to pinch off the rubber brake lines to the calipers. If the pedal becomes solid, you know the issue is on the caliper side. Then remove the vice grips one at a time, testing the pedal after each one, and your the location of your issues should be pretty easy to determine. 

EDIT: Do NOT do this if you are using steel braided brake lines, such as those that come with a BBK. It WILL  permanently ruin your lines.