I just changed the brake pads on my Brembos for an autcross race tomorrow to Cobalt GT-Sports pads. When I went to bed the pads the brakes were really soft and never got better. Do I have to bleed the lines if I just change pads? I changed to Nismo pads for daily driving and this wasn't a problem. How is it possible for air to get in the lines from compressing the pistons? Any tips, my race is in 12 hours. Thanks.

 

Its the first thing I would do.

 

^yep, bleed the lines whenever you change your pads

 

Will do, thanks.

 

Did it fix it? You sure you got enough heat in the pads during bed in? Did you do 10 stops then rest and do 10 more? I bet race pads take a good bit of heat to get real grippy.

 

Bleeding the brakes made it a lot better, but it still would get pretty soft going into some of the turns.

King Tut - I bedded them correctly and they grip really well, the pedal was just soft, like I had air in the lines. I plan on completely flushing my fluid and putting new in so we will see if that makes a difference.

 

Try following my bleeding instructions here: http://www.zeckhausen.com/bleeding_brakes.htm. You can skip over all the apple pie and motherhood stuff about why it's a good idea to bleed brakes. Focus on the little tricks, such as using the two-person method and using a rubber mallet to tap the calipers in order to free trapped bubbles.

 

Good write up, but ther is one more thing that I have learned with the 350Z. For some reason, bleeding the brakes while the car is running has a MUCH better result than when the car is not running. When I changed my lines, I bled the brakes 3 times with the car turned off and the pedal was still soft. I bled them once with the car running and the pedal was hard as a rock.