Installed the TRW GT3 master cylinder on my 2011 Cayman S today, and I've somehow made the excessive brake pedal travel (or "mushy" brake feel) worse. I suspect this is a result of a less than optimal bench bleed of the new master cylinder but can't be sure. The new MC didn't come with a bench bleed kit, so I improvised by holding the MC in a vise with the reservoir attached to the top of the MC while a friend kept the holes that connect to the brake lines plugged while I slowly pushed the piston in and out.
Another potential issue during the install was my inability to attach the new MC into the brake booster with the reservoir still attached because the reservoir was in the way. As a result, I removed the reservoir, attached the new MC and then reinstalled the reservoir. After getting everything reassembled. I filled the reservoir, and bled the system twice (via the calipers) using a Motive Power Bleeder.
So far, I've seen no improvement in brake firmness... In fact, it feels softer now. The only other thing I can think of that's causing this (besides possibility of an incomplete bench bleed) is that I have the wrong part. I ordered the part from ECS tuning and the part number on the box does match the part number listed in other threads on this site. I'm sure that possibility is a long shot but really can't think of any other reason why this is happening.
Did I miss a step? I'm thinking my only two options at this point are to remove the MC, bench bleed (with a kit this time), and bleed the system again. Or, hand it over to one of the pros at my local independent shop and have them do the same thing but also flush the ABS (which I am unable to do).
Any thoughts or suggestions are greatly appreciated.