Soft Pedal

North Coast Cab · North Coast Cab's Garage

I spent two days at Beaver Run this weekend with Nasa. On Saturday everything was great. On Sunday when I got in the car the pedal went 1/2 way to the floor. I pumped it once and it seemed ok. I went out on the track and it was very soft again. If I used the brakes fairly often it seemd ok. If I went through a few turns and long back stretch when applied it would almost go to the floor the first time and then be firm the second.

After the first session I completely flushed the brake fluid, but the results were the same. I ended up learning a little different driving method and finished the day. Also had must best time in the afternoon.

So, what do you think? Master cylinder, contaminated fluid, vacuum boost?

Thanks, John

jacko241 · 06-12-2005, 03:42 PM

Sounds like master cylinder.

89911 · 04:32 PM

I had this problem, and it turned out to be my rear axle nut had loosened. Of course, there was some funky handling issues, but the thing I noticed first was the soft pedal and then pumping it up to brake. Turns out the rotor was wobbling in the calipers, pushing the pistons in. When I would go to stop, I would hit the brakes and need to pump them a few times to get the pistons on the rotors. Have you checked for any wheel play? Did you get dizzy from BeaveRun's minute laps? I personally don't like the track that much, not enough passing straights. You picked a hot weekend!

North Coast Cab · North Coast Cab's Garage

I checked the wheels and there was no bearing play front or back.
I like Beaver Run myself. There were three of us there together with our 911's and about another 5 including a 964 cup car. I timed myself for the first time and ran a 1:12 this morning while dealing with the brake issues. Pretty happy with that.
Also, Nasa is running a one day Mid Ohio event Friday August 1st if you're interested. I know of a whole bunch or Porsche guys going.
John

sangeun · 06-12-2005, 04:42 PM

I would check the bleeder valve for leak. I had similar issue on my '88 911. Mutiple brake flush & new MC did nothing to fix my problem. It ended up being a small leak at the bleeder valve on the rear calipers. Clean off the caliper round the bleed screw and pump the brakes several time. ome back in about 15 minutes and check for any wetness.