Acura RDX Brake Caliper Refinishing and Full Brake Service

Lift and support the RDX on stands, then remove each road wheel. Note the fastener sizes before you begin: bleed screws take a 10 mm wrench and the banjo bolts a 14 mm. Front guide pins need a 14 mm socket while a 19 mm open-end wrench holds the pin from turning, and the front bracket bolts are 19 mm. At the rear, the guide pins use a 12 mm socket with a 17 mm open-end wrench on the flats, and the bracket bolts are 17 mm. Unbolt each caliper bracket and slide the caliper clear so the body, bracket, and hardware can be worked on the bench.

Put on nitrile gloves so skin oils do not contaminate the surfaces, since POR-15 is unforgiving about oil films. Scrub the caliper bodies, brackets, and anti-rattle hardware down to sound, bare metal. Wash every part using only a water-based degreaser; the film left behind by acetone or ordinary brake-parts cleaner will stop POR-15 from keying to the metal. If a piston is corroded from a torn dust boot, it can be pulled and cleaned, as the caliper separates with just a snap ring and the boot.

Mask off anything that must stay paint-free. Decant the POR-15 and lay it on with disposable foam brushes; trim one brush to about a 5 mm tip to reach recesses. Because POR-15 carries no UV resistance and will chalk if left bare, it must always be top-coated. The window for a chemical bond with the color coat lasts roughly 4 to 6 hours, so plan the top coat inside that span. Alternatively, let the POR-15 harden fully and scuff it with light sanding to give the color coat a mechanical bond instead.

Before spraying the calipers, test the color on a scrap metal coupon painted at the same time; wait about 15 minutes and confirm even coverage with no wrinkling. The writeup used VHT Gold followed by VHT Clear. Use only heat-rated caliper or engine paint. Cure the VHT by baking at 200 degrees F for one hour. Note that POR-15 itself does not require baking, but the VHT caliper paint does need that cure.

Measure rotor thickness at several points around each disc. The front service limit is 26 mm and the rear is 7.5 mm; the writeup's fronts measured 27 mm. A rotor with no pulsation, no scoring deep enough to snag a fingernail, and thickness above the limit can be reused. Check the parking-brake drum inside the rear rotor hat: nominal is 200 mm with a service limit of 201 mm. The parking-brake shoes should be around 3 mm, with a 1 mm limit. Clean surface rust from the rotor edges and hats and dress the bare spots with rust converter or POR-15 to slow further corrosion.

Clean the hub face until it is smooth, because any runout there is amplified at the friction ring and shows up as pulsation. Since the rotor screw holes index only one way, seat the rotor accordingly and snug it with lug nuts over nylon washers to keep it true while you work. Test-fit the pads and sand the ear contact points so they slide freely. On the front, the screech clip sits on the leading edge of the inner pad, which is the upper edge. Install the sleeved guide pin in the upper position and the flat-sided pin in the lower. Lightly grease the pad ears and keep all grease off the friction faces. Torque the bracket bolts to 101 lb-ft and the caliper guide-pin bolts to 37 lb-ft.

Retract the rear piston by pushing it straight in; no rotation is required because the RDX parking brake is a separate shoe-and-drum unit inside the rotor hat. Use a large C-clamp or a dedicated piston tool with an old pad as a cushion, and watch the reservoir, as displaced fluid backs up through the system. On the rear, the leading edge of the inner pad is the lower edge, so set the screech clip there. Orient the rear guide pins with the flat-sided pin on top and the round pin on the bottom. Fit the flat anti-rattle clip at the top of the bracket and the ribbed, drain-holed clip at the bottom. Torque the rear bracket bolts to 80 lb-ft and the rear guide pins to 17 lb-ft.

Pressurize the system with a power bleeder, or use a vacuum bleeder, and work through the corners beginning at the left front, moving to the right front, then the right rear, and finishing at the left rear. If you forced fluid backward while retracting the pistons, either hold vacuum on the open bleed screw continuously or purge the old fluid with a follow-up bleed. Use Honda/Acura brake fluid. Refit the wheels, confirm a firm pedal, then bed the pads with a series of controlled stops before returning the vehicle to service.