failed master cylinder?

ajrn

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#1
New guy here. Sorry for the lack of intro. I'm at work.

My ex g/f called me as the brakes on her 09 Focus SE failed.

I assumed she'd ran the pads into the rotor, but the fronts still had plenty of meat on them. (at least 50%).
The fluid was a murky gray, the pedal has very little authority-- and slowly goes to the floor. Hoping that she'd cut a line, or maybe one had rusted I had her come out and push down the pedal.
IT bubbled (air) into the brake fluid reservoir. I assume failed brake master cylinder, but I've never seen one blow air into the reservoir.

I tried briefly to bleed the fronts, but the bubbling continued as I made attempts to do this on the fronts (Yeah, I realize you'd start from the passenger rear-- but I think the problem is the MC, not air in the lines).

Is there anything special I need to know about replacing the master cylinder, or any tips from someone who's done one on this? Looks like it should be pretty easy to get at, once the battery, and maybe that fuse box are out of the way.

Thanks in advance

AJ
 

ajrn

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Has anyone here replaced one. It looks like if you remove the battery (done) and can shift the main relay/fuse box (loose but not moving much) it should be very accessible.

I've removed a screw at both ends, and slid the outside (fender side) of it off a metal tab. It looks like removing the battery tray so the u-shaped battery bolt (that holds both sides down) will work, but the bolts holding it (and the battery tray) in place are rusted. I hit them with PB blaster and will check on them, likely tomorrow, when the new master cylinder arrives.

Any tricks to getting the reservoir hose off the master cylinder?
 

ajrn

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#3
I'll be doing a write up (post facto) of the replacement. I took a few pics putting it back together. I did learn a few things that would be helpful to know if you end up replacing one. :(
 

ajrn

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#4
The short list
You'll need to remove the battery and battery tray.
You'll need to move the electrical fusebox/relay junction box
The reservoir attaches to the master cylinder with a connector that you PUSH IN to to disconnect. YOU DO NOT NEED TO USE A TOOL, just push on it with your thumb.
A hint on replacing the master cylinder.
Connect the back lower line (if it's the 4 line/non-traction control master cylinder first) with the master cylinder rotated 90 degrees from the firewall.
THEN insert it in the firewall, and put the nuts on, just enough that they don't fall off. (Keeping it free to wiggle will make the other line placements easier) do the front lower, then the rear left side/front left side) It'll be obvious, when you look at it.
Then reconnect the reservoir.
It took nearly a GALLON of brake fluid, to clear the contamination, from all 4 lines. SO you might want to figure this into your "purchases."

It's not "horrible" to do, but my first replacement failed on arrival, so it became an ordeal.

The car is having a no-crank/no-start issue since the replacement. At first, I thought it was from the disruption of the junction box, but now I'm chasing who knows what.
 


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