912 BrakesThe first time I drove my new 912 I knew the brakes were a high priority item. They were spongy and not very effective. The previous owner thought that bleeding them would be sufficient. After some reading about brake problems which describes old brake lines that swell shut on the inside, I decided to buy new ones.
Steel braided brake lines come in two levels of quality. Normal ones had problems passing some sort of whip test with the Department of Transportation. There are DOT certified ones which have about a $30 premium.
Part numbers, descriptions are from Strasse unless otherwise noted. The owners manual recommends 'ATE Blue' brake fluid. This is about the 3 times the price of ordinary DOT 3 fluid. The material selected is compatible with DOT 3/4 according to the information on the can.
The front lines are relatively easy to replace. The body end is held in with a U shaped sliding clip that fits into a slot in the fitting. You can rotate the clip 90 degrees by tapping a notch in the outer corner of it in order to get access to the back side. Use a drift punch and hammer.
Access to the rear inboard line fittings requires removal of the rear engine mounts. The drivers side brake line seems to be the hardest to remove.
The front left bleeder valve could not be opened with a wrench out and was replaced. An 'easy-out' from my brother Rick worked to free it in combination with water pump pliers. Found several metric bleeder valves from Kragen, one of which fits. See the part number above.
I replaced lines and flushed the fluid, using the ATE Blue as a replacement.
There are a number of references on the WEB to frozen caliper pistons. I do not believe this is problem on my car so I've not torn them down.
I was reminded by some email that I still had one brake line that I had not changed.