Did you / they bench bleed the new master cylinder? Did it ever run dry while bleeding?
I don't trust Rock Auto remans -- same as I don't trust the Pepzones that are pushing the same stuff. Same bore doesn't mean it has the same stroke. Who knows if someone sent back a wrong core? Mid-year changes, etc. The new MC could be bad right out of the box too.
The one thing I'm sure of -- you've driven that godforsaken thing for 100k, you know how it should feel, or at least the normal lack of sensation and comforting embrace of familiarity. Something is wrong.
There's no such thing as a shop I trust, only shops I trust to make it right when someone screws up. Maybe it had air trapped that they cleared, but then adjusted the rear shoes the wrong way and you're getting pedal travel there? If nothing obvious jumps out, then you have to start over at square one and assume nothing.
I'd work it systematically, with a visual inspection of the mechanical parts -- pads, sliders free? No leaking pistons? Then I'd be tempted to replace that MC and triple check that it's the correct one for your application and bench bleed it well. Then rebleed the whole system with a gravity bleed, followed by a tried and true two-man bleed job.
Unlikely this is related but throwing the thought out any ways. Early Ford Fusions have an active NHSTA "engineering analysis" for the ABS module HCU. My son's Fusion had the issue and the brake pedal will travel roughly an extra 2 inches before firming up and it will feel fine once you hit that level of travel. He had gotten used to it after a couple of years but when I would hop in the car it was a bit unnerving the first time you hit the brakes. The answer for his was a junk yard ABS module and bleeding of the system including the ABS.
From the investigation "VRTC was able to confirm stuck valves and corrosion of the zinc coated control valves, and it's testing indicates that HCU failures cause increases in pedal travel that may affect braking distance."
Alright, I think I'm done letting other people work on my cars. Someone in this thread suggested that if the shop didn't activate the ABS while bleeding the brakes, that could lead to this problem. That had been nagging at me a little bit, so I called the shop and asked about the procedure they used. The guy told me he didn't bleed them. He just adjusted the rear drums and the parking brake. When I brought the car in I described the problem and told them, "I think the brakes need to be bled really well. Can you check for any other problems with the system while you're at it?" Apparently I wasn't clear enough.
So I'll be bleeding the whole system again. Any tips for activating the ABS during the process? I'm finding conflicting reports about whether or not it's really necessary, but if it's possible I'd like to eliminate that as a possible problem.Car is going on jackstands this weekend, and I'm going to solve this problem. I'll probably replace a section of hard line that is looking pretty rough while I'm at it.
you do not need to activate the ABS.
In the past, I have bled the brakes, then went out on back roads and activated ABS multiple times and re-bled. Seemed to have worked for me....
