theredgmc

I already have them reassembled sitting in my shop. But I posted this info on a different page. Sorry if the images seem out of order.

"If you’ve ever wondered why the 2019+ 4 piston calipers have a ridge on the outside, here’s why. It’s for fluid passage, but the whole ridge does not allow for fluid passage. Fluid only passes at one small point in the center. The GM design is a small passage drilled at an angle, at the bottom of the cylinder bore. Also GM only drills one passage for fluid flow between the half’s.
I could not get an accurate measurement for the outer surface thickness. But if you grind that whole ridge off and develop a pinhole leak in the center, you now know why. As a guess, I’m thinking the outer ridge runs the whole length for more aesthetic purposes. It would look strange if it only had one lump in the center between the pistons.
I bought this set to basically take apart and see how they were made, and to get the piston diameter. Excuse my messy lines, but you get the point."

timharber

Thank you! I think I'll try the spacers until I can find some new model wheels that will work.

Sloop

iTrader: (2)

Anybody know if the 18” trail boss wheels will clear the PPV calipers?

shakenfake

@Sloop You ever get that timing cover sent out?

I believe they do though.

Drspencer

iTrader: (1)

While this thread is still going, thought I would add some feedback on new pads. The GM Brembo pads create A LOT of dust, like...powder everywhere. I replaced them with a set of generic ceramic pads, they were $60, Powerstop 172407 from Rockauto. Work great, hardly any dust on the wheels after a week of city driving.