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Discussion Starter #1
A little long winded here...
My wife's MDX had a soft brake pedal, so while we were getting her tires rotated I asked if they would bleed the system (flush/bleed). Get a call that there is an issue they cannot resolve (system will not build ANY pressure) and had to have it towed to the stealership.

Stealership tries to flush the system and finds the same issue. Their diagnosis is bad master cylinder.

So instead of paying $600+ I have the MDX towed back to my house and go to replace the master cylinder (ProStop reman'd) and find that the brake booster rod is bent and has come loose. So I replace the brake booster (Cardone reman'd), bench bleed the MC and put everything back together. I then bleed the MC again and bleed all the lines (RR,LF,LR,RF) using a vacuum line.

After all this I still have a soft pedal and now have a hissing sound coming from the booster while the pedal is depressed and after while the pedal travels back to top.

The reman'd booster did not have foam on the area that contacts the firewall, so I'm not sure if that's why I hear the hissing more. The vacuum line is connected to the booster.

What am I missing here?!?

2002 MDX
Yes I used Honda fluid
 

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A little long winded here...
My wife's MDX had a soft brake pedal, so while we were getting her tires rotated I asked if they would bleed the system (flush/bleed). Get a call that there is an issue they cannot resolve (system will not build ANY pressure) and had to have it towed to the stealership.

Stealership tries to flush the system and finds the same issue. Their diagnosis is bad master cylinder.

So instead of paying $600+ I have the MDX towed back to my house and go to replace the master cylinder (ProStop reman'd) and find that the brake booster rod is bent and has come loose. So I replace the brake booster (Cardone reman'd), bench bleed the MC and put everything back together. I then bleed the MC again and bleed all the lines (RR,LF,LR,RF) using a vacuum line.

After all this I still have a soft pedal and now have a hissing sound coming from the booster while the pedal is depressed and after while the pedal travels back to top.

The reman'd booster did not have foam on the area that contacts the firewall, so I'm not sure if that's why I hear the hissing more. The vacuum line is connected to the booster.

What am I missing here?!?

2002 MDX
Yes I used Honda fluid
Are you saying the original factory booster rod self-destructed on its own? Maybe whatever caused the original booster to fail also affected the new one. Also quite possible that the remanf Cardone is bad out of the box. Did you leak check it?
 

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That´s pretty bizarre..
Soft pedal is always an issue with AIR in the system.. In all my years flushing brakes I can safely say not ONCE have deal with a soft pedal issue that didn´t end up in AIR in the system...

Try to do the ABS Check Purge twice
Drive to 35MPH and do a Full Stop (Pedal to the Floor) and Repeat 2 times in a Row..
Drain the System again.
 

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Discussion Starter #4
Are you saying the original factory booster rod self-destructed on its own? Maybe whatever caused the original booster to fail also affected the new one. Also quite possible that the remanf Cardone is bad out of the box. Did you leak check it?
It looks like the original booster failed because of the retaining clip that holds booster rod in place...atleast that's all I can see.
I've done the basic check of disconnecting the vacuum line to make sure the new booster is working, but why would that cause a soft pedal? I thought a bad booster = hard pedal due to a lack of vacuum.

I bled the brakes by running a 16' 3/16" hose from each bleeder valve back to the master cylinder since the system was already flushed and has new honda fluid in it. This allowed me to see the cycle of fluid and check for air (which I saw none.) Also saved me from using 3-4 pints of fluid :)
Today I'm going to clamp the rear brakes off to determine if its a front or rear issue and then go from there.
 
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