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Diagnosing Braking Problem

Yea for sure. It also makes sense its the rear caliper because the air going into the MC was consistent in the rear portion. Not so much the front.
 
Hey guys so im still dealing with the same problem. I put the correct caliper and bled. The pedal gets tight then as soon as I start the car the pedal is a sponge. If i pump afew times it will semi tighten and the brake failure light comes and goes. I bled the MC several times on the car as per pedal being held down and opening the lines. Air continues making its way into the MC.

My car is non ABS. Check valve is getting vacuum. All I can think of is the rebuilt MC from Advance is junk. I can remove it and bench bleed again but I dont know if that will help. I’ve seen talk of the brake junction/octopus but idk how common that is
 
Probably not your issue, but I'll throw it out there anyway.

In the past I've cleared a "brake failure" light on my '82 244 Turbo by removing the wire from where it attaches to the proportioning valve, then removing the fitting it attaches to at the valve, exposing the inner valve.

Then I'd poke a narrow rod in the valve, pushing it in.

I'd read to do this to reset / rebalance the valve if it got out of whack.

Works.
 
Well the light is only coming on because im still having brake issues. Its not the light thats the issue, its the braking causing the light to turn on. When the issue is fixed the brake failure light will go off
 
Hey all I bench bled the MC and that was the problem. An unruly amount of air! How does that even happen? Anyway all seems well for now
 
Great! Nice to sort it out. I bench bleed the new master cylinders nowadays even with using the power bleeder. Air gets stuck in there and well you know what to call it. :lol:
 
Hey all I just wanted to add that my Bosch check valve/New Oring came in for the brake booster and WOW what a difference. The brake pedal is probably 30% stiffer and less spongy for sure. The old check valve was getting suction but my first analysis was right. Compared to the new one it was probably allowing about 50% vacuum through. The new check valve is bringing through alot more force.

I definitely wouldn’t overlook this part if decades old.

Thanks!
 
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