Car: 98' C280 with single pin style brake caliper

Piston angle position:
Looking in FastLanes tools catalog, I see a ‘brake piston angle gauge‘, to get the piston face indentation positioned at 20 degrees. I take it that the angle of the indentation on the face of the piston is important to how the pad contacts the disc surface. I also take it that if the piston angle is incorrect, this could cause brake squeal, as the angle the pad touches the disc is off. When I replaced the brake pads a few months back (but not disc), I may have rotated the pistons as I pressed them in. And since my car's rear brakes are squealing so bad, I thought I'd check to make sure the piston angle is not off before going through the expense of buying new disc and new pads to rid the squealing once and for all. Looking at the brake piston angle gauge' tool on FastLane, I'm not sure how the tool is inserted (inserted from the rear part of the caliper maybe???), and which 20degrees to check? To be more precise with my question; If I'm looking at the caliper mounted on the car, with the pads removed, which direction should the indentation be facing (down, back etc.)? Or lets say the passenger side caliper, facing the caliper kneeling and looking from the passenger side, pads out and I’m looking at the inner piston face, what direction should that indentation be facing?

Caliper rebuild kit:
I take it that the metal part shown in the kit below is merely a tool to install the rubber parts?



TIA
MarkC

The "metal" parts are the pad STOPS & they are the reason that the 20deg angle is suggested as they press into the piston.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

What do i know ?
But aren't they the mark for the relief ground into the piston to stop[ the break squeal
if the caliper is mounted on the left side or the right sibde os the axle the relief on the 9 o'clockk side be lower side and 3 o'clck move piston to upper side
That's what is stated in the shop cd
Just my 2 cents

__________________
[B]Mike Y.
00 sl500 sport
88 560 sl (sold)

Pad stops? So they attach to the pads and the caliper piston face inserts into the opening and touches the pad? I don’t understand how it works. I did learn however that the pictured kit isn’t listed for the single pin caliper which my car has, but I wouldn‘t be surprised if it’s very close.

Since this is on a CD, is there a way to view an image?

The pic below is of the left side (driver’s side) rear caliper. Though I have the single pin caliper, I'm sure that teh piston cutout would face in the same direction. It appears from the pic that the cutout would be facing down toward the ground, when the caliper is mounted. Is this correct?



Thanks
MarkC