[javadog]

This is relatively easy to diagnose. First, try to understand how the system is laid out. You have a pedal that pivots on a pair of bushings. That's the first place you can have wear, although that won't cause your problem. Secondly, the pedal is attached to a pushrod. Grab the pedal with one hand and the pushrod with the other and move them. If you have relative motion between the two it should be obvious. It will occur at the rod end that attaches the rod to the side of the pedal. While you are down there, grab the brace that attaches between the pedal cluster and the brake booster and try to move it. It should be solid.

Next, go in the trunk and decide if you want to keep screwing with this. The next link in the system is a lever that pivots inside the brake booster bracket. The pushrod from the brake pedal pushes on one end of this lever, it pivots and then pushes on the rod coming out of the brake booster. The main possibility for play at this end is in the clevis connection between the end of the push rod and the lever. This connection is has a fair bit of clearance, as does the connection at the other end of the pushrod, at the brake pedal. It was never designed as a close tolerance fit. There is also a clevis at the lever-to-booster joint, which can have the same play as the clevis at the end of the pushrod. (Earlier boosted 911s don't have a clevis at the booster end of the lever, just a cup that pushes on a ball on a rod protruding from the booster). You might also have a little play where the lever pivots in the booster bracket.

The bad news is that you can't see much of anything on this end without taking it apart. That is a bit of a pain in the rear. The other bad news is that you can't improve it much. You can replace all of the parts that wear with new ones, which might help a little. You can refit the joints with parts of your own making to reduce the clearances.

Or you can realize that this is pretty normal (call it tolerance stack-up), made to seem worse by the leverage ratio built into the pedal geometry and go find something else to screw with.

JR