wcbrusm

My front brakes are locking up on my 1999 996 Carrera cabriolet. I notice a few weeks ago when someone pulled in front of me, and I had to hit the break hard. During normal braking, the problem does not occur.

The technician who is working on my car thinks the ABS is engaging too early. He so far has flushed the system and confirmed that the wheel and tire size is not affecting the ABS. They are factor size. Has anyone had this problem before?

Mike Murphy

If you hit the brakes hard immediately, on worn tires, there no traction. Theres no weight transfer.

If you have good tires and progressively apply the brakes for a panic stop, it’s much better.

Can you feel ABS engaging? Have you tried testing a progressive panic stop in a safe way (nobody around)?

PatMc

Describe the symptoms you're experiencing.

Locking up and early ABS activation are sort of opposite each other.

wcbrusm

My tires are older, so the tech swapped them with wheels with newer tires to see if the problem went away and it did not. The first time I noticed the issue was cruising about 60-70 and an oncoming vehicle turned left in front of me. I got on the brakes hard to avoid hitting them. Later I did what you said at slower speeds (20-30 mph) and progressively hit the brakes. The front wheels were locking up. At the slower speeds, it was not a constant lock. It felt like the ABS was releasing the brakes just not fast enough.

Mike Murphy

Have you checked to see if there are any ABS codes?

blacksquid

Check reply #11 in wheels locked thread.