went from 13/16" to 15/16" master cylinder, couldn't change 4040 proportion valve because need to oreder and bend a new line. But the trouble is now after 6 bleedings, the pedal barely touches the floor.

could it be because it needs the 4040 proportioning valve, or was it just a bad master cylinder?

 

did u bench bleed the MC b4 u hooked it all back up

 

yes i did

 

it has the symptom of a bad master cylinder, it's pretty stiffed when the car is off, but after driving, it floors.

 

help!

 

Bleed all the air from all 4 brakes... Get a friend... start with the farthest brake, have friend pump pedal 4 times and hold it down. You then open the bleeder line and your friend will tell you the pedal is now down. While he holds it down, you close the bleeder valve. Then repeat the process on that same wheel until all air bubbles are gone. Make sure fluid does not run out in the reservoir. Then repeat on the rest of the wheels.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Del Sol on Steroids &raquo;</TD></TR><TR><TD CLASS="quote">went from 13/16" to 15/16" master cylinder, couldn't change 4040 proportion valve because need to oreder and bend a new line. But the trouble is now after 6 bleedings, the pedal barely touches the floor.

could it be because it needs the 4040 proportioning valve, or was it just a bad master cylinder?</TD></TR></TABLE>

the car was bled a total of 6 times.

1.bench
2.m/c installed
3-6. all four brakes

 

Is it a used MC? Does it hold pressure when you pump the brake repeatedly, and then slowly sink to the floor with steady pressure? That's what my used 1" MC did after driving around for a while, or on hot days when it'd get heatsoaked. Replaced it with a reman 1" MC, and that fixed it.

 

new from autozone, replacing that now with new oem. maybe it was just a bad MC. and no, the pedal would just go to the floor, woould hold pressure. it would engage the brakes but at the floor.

it hold super stiff when engine is off, but when you ride it goes straight to the floor.