MKIII Rear Brake Overhaul / Toyota Rubber Grease
 

I was monitoring my rear brake pad wear and discovered that the inside pad at the bottom was wearing much faster than the top while the outside pad was square and wearing evenly. I came to the realization that the lower slide pin was being gripped by the rubber boot that it slides in because I had used petroleum-based grease (bearing grease) which swells up the rubber and grabs the pin restricting movement so that it can't back away. Why the outside pad wore, square I don't know. The upper pin is in a metal bushing so it doesn't matter which type of lubricant you use and the manual does not specify. The Toyota manual says to use Lithium base glycol soap grease (08887-01206). Toyota calls it rubber grease. You're supposed to use it on the caliper seal and piston, inside the slide pin boot for the pin to slide and on exterior rubber parts. If you use the wrong kind of grease on the piston seal it will swell up and grab the piston and keep it from moving properly like the slide pin. Rubber grease is about $15 a tube at the dealership but I picked up some on eBay for less. It's pink in color like some of the accessory bags that come with Toyota brake parts. Some people use silicone grease, but I'm not taking any chances. I got rebuild parts for the caliper on eBay and Beck-Arnley rotors from RockAuto. The pads were PBR premium ceramic that came with shims attach so I didn't have to buy a shim kit. I did the parking brake with Centric premium brake shoes but they needed a tweak where the parking brake arm rivet goes through. I had to press one out and clean up the burs and press it back in. Someone on Amazon had the same issue. Centric uses a gripy semi-metallic shoe compound where stock, I believe, is organic compound. Its basic function is a parking brake and it's a piss-poor emergency brake, even brand-new. There is just not enough surface area on the shoes to stop a heavy car quickly. After bedding the shoes and the disk pads, the results are a little better than before the overhaul. I had to make a tool to get the spring retaining pin caps for the shoes to twist on and stay on. I took a 14 mm 3/8 drive craftsman socket and put masking tape across the top in 2 directions, then I poked a hole in it. I put the socket on a 6 inch extension with a 3/8 to 1/2 converter on the end as a handle. The tape provided enough friction to grip the spring cap and twist it while pushing down to get the retaining pin through the slot in the top of the cap while holding the pin base against the back plate with the other hand. I checked the run-out on the disks with a nice clamp-on dial indicator tool kit from Harbor Freight. The limit is 0.005" The best I could do on one side was 5 thousandths after moving it around the 5 positions possible (the worst one was 7 thousandths and out of spec). The other side was 0.002 on the 1st try and I stopped.

See photo