[volksworld]

just to make you feel more wonderful the AC Delco masters are made by Brake Parts Inc in china and aren't a "real "chevy part...they also make Raybestos and NAPA stuff...found out when they had a recent recall of all 3 brands on a master that was locking up....so i doubt your dealer will source it from them...been at least 15 years since my master swap but i swear manual masters were 1 inch and power were 1 1/16 or 1 1/8...a bore thats too small will give you excessive pedal travel, too large a short throw that's too hard to push...a lot of the aftermarket power disc conversions used the Vette style master with the equal size front and rear resevoir sections (which lets you use them with disc/drum or disc/disc applications) and that's what it looks like they put on your truck...idk if a stock master is compatible with whatever they supplied as a booster...Rockauto is one of the few vendors that uses the actual picture of the part you're getting and not a stock photo of something similar...the Delco one they sent you looks more "oem correct" than the one in the Summit picture...a rock hard pedal is usually lack of power assist...bad check valve or bad booster