Does anyone have a link to a write-up on how the calipers work? A tech white paper or similar?

We all know you have to screw in the pistons when replacing pads. But here is something interesting. Some new pads come with a center "peg" and some don't. The peg fits in one of the 2 slots in the end of the piston. So the piston has to be indexed correctly for the peg to line up and the peg presumably keeps the piston from turning as it advances.

So either A) half the pads on the market are wrong and result in improper operation or B) it doesn't matter if the piston turns or not. In which case the pegs are pointless and the pads with pegs are... well, let's just say not made by geniuses.

Would appreciate any info on this topic.

 

NOTE:Perform Step #1 through Step #7 on each side of vehicle to complete pad set installation, then proceed to Step #8.CAUTION:Anytime the brake rotor or brake pads are being replaced, the rear caliper piston must be seated (bottomed) to compensate for the new brake rotor or lining. Because the parking brake self-adjuster mechanism is attached to the piston, a special seating method is required. The only acceptable method is by rotating the piston back into the bore using Retractor, Rear Caliper Piston 8807 , as described below. Any other seating method will damage the self-adjuster mechanism.


1.If necessary, seat (bottom) the caliper piston in the bore as follows:a.Assemble a 3/8 in. drive ratchet handle and an extension (3).b.Insert the extension through Special Tool 8807-1 (2).c.Place Special Tool 8807-2 (1) on the end of the extension.d.Insert lugs on Special Tool 8807-2 into notches in face of caliper piston (5).e.Thread the screw drive on 8807-1 down until it contacts the top of 8807-2 which is against the caliper piston. Do not over tighten the screw-drive. Damage to the piston can occur.f.Turn 8807-2 with the ratchet, rotating the piston in a clockwise direction until fully seated (bottomed) in the bore. It may be necessary to turn 8807-1 with 8807-2to start the process of piston retraction.
2.If caliper adapter was replaced, install caliper adapter bolts (2) and tighten to 100 N-m (74 ft-lbs).

NOTE:There are two different abutment shims. If installed in wrong orientation, pads will not fit properly. NOTE:If the brake pads have a protective paper on the rear face of the brake pad plate, it must be removed before pad installation.3.Assure adapter abutments are free from debris or corrosion. Apply an even layer of MoparŠ Brake Lubricant or equivalent to entire area of four abutments PRIOR to shim installation. Install four new pad shims (4).4.Place the brake pads (2, 5) in the abutment shims (4) clipped into the disc brake caliper adapter bracket (3) as shown.

CAUTION:Use care when installing the caliper (2) onto the adapter bracket to avoid damaging the guide pin boots.

CAUTION:When removing or installing a caliper guide pin bolt, it is necessary to hold the guide pin stationary while turning the bolt. Hold the guide pin stationary using a wrench placed upon the pin's hex-shaped head.

5.Install the disc brake caliper (2) over the brake pads on the brake caliper adapter bracket.6.Align the caliper guide pin bolt holes with the adapter bracket. Install the upper and lower caliper guide pin bolts (1). Tighten the guide pin bolts to 35 Nˇm (26 ft. lbs.).

7.Install tire and wheel assembly (1) (Refer to 22 - Tires and Wheels - Installation) . Install and tighten wheel mounting nuts (3) to 135 Nˇm (100 ft. lbs.).8.Lower vehicle.9.Pump brake pedal several times to ensure vehicle has a firm brake pedal before moving vehicle.10.Check and adjust brake fluid level as necessary.11.Road test vehicle and make several stops to wear off any foreign material on brakes and to seat brake pads.