An ABS module "could" be your sinking pedal problem
Sinking/Spongy Brake Pedal???? With ABS SYSTEM!!...Watch this before you buy a master cylinder!!...It does happen...Its Not always a Master Cylinder Issue! ...Must Watch! You can use this way to fix car,that many DIY car guys tested it with their car model. I have collected those tested models,Please check below. 2005 GMC Sierra,MINI Cooper,2008 ranger,chevy k2500,98 Toyota 4Runner, 2001 FORD ClubWagon,2013 Ford Edge,mustang 2012,02 Mountaineer,2011 Hyundai ,Genesis 4.6,2002 chrysler, Nissan altima,199 toyota camry,99 F-150,2007 Expedition,2001 Escape,Peugeot,99 Jimmy,2003 e450,2003 F150, 2014 Wrangler,98 Explorer,2003 Ford Focus,07 Mazda,Toyota Camry 2005,Ford Fusion, 2006 Toyota Sequoia,95 chevy k1500, F150,98 camry,Jeep Grand Cherokee,2004 Expedition,ford f350,2001 ford f150. I will upload more tested car model in future,Thanks!