rsglaab

I have a supercharged ws6 that I use for autocross racing. I have been using it for 3 years with no problems. I went to a race a few week ago and on one of my runs it had a high hard pedal with very little brakes on one corner after that it seemed fine until a run later in the day it did the same thing. I put on a new brake booster with a new check valve plus a brass check valve to be sure no boost was getting into the brake booster. went out on 2 more races with no problems. Went out last week and it did the same thing again. I just pulled of my lineloc but I still don't know if the issue is solved. All brake lines and pads look good and no ABS light. I have another event on the 18th and I would sure like to have brakes that I can trust.
Sean

z28bryan

iTrader: (7)

I've had problems like you describe. I'm not sure if it's the ABS "ice mode" that I've read about on frrax or not. Once I DNF'ed because I hit the end of the stop box because of it. From then on I slowed down before I crossed the timing light so it wouldn't happen.

I haven't experienced it in a while now though. I think a better "squeeze" of the brake pedal prevents the hard pedal for me. I noticed it mostly happened when I would "stomp" on the brakes. It's a good autox habit anyway.

Major_Lee_Slow

iTrader: (1)

Does it feel like all of a sudden you lost power brakes, or does it feel like the ABS is engaged?

rsglaab

It feels like there is no power assist if you let off and hit them again they seem to be ok

Major_Lee_Slow

iTrader: (1)

I wonder if you are just loosing vacuum assist due to the blower? The check valve would prevent boost from getting into the brake booster, but it still needs a vacuum. Maybe you need to change the brake booster vacuum line routing so that it's upstream of the blower.

This is just a theory. It may be possible that the brakes feel correct when you lift and reapply because there has been time for the motor to make vacuum vs. when you go straight from throttle to brake. Does this make any sense?

When you drive "normal" on the street, do you have this brake issue or do they work fine?

Breathing Fire

I don't know if this will help, but I had the same problem. It started after I changed pads. I was in need of them right away so I got the ceramics at the local parts store. Once they were on I had that problem. Tried for months to figure it out, but never could. Then it hits me that the only thing different was the pads. Ordered some hawks and haven't had the problem in 4 months. Before it was a regular thing mostly when the brakes were cold.

rsglaab

I have driven it on the street and autocrossed the car for 3 years with this configuration without a problem until this year. I thought it may be a vacuum issue too but I don't have any other place to draw vacuum except the manifold which is under boost pressure at some times. I put a vacuum/boost gauge in the car and under normal driving it has about 14 in. when you have it full throttle and its making boost then you let off it goes up to 20 in. of vacuum. I have the front brakes off the car now, the hawk pads look good except for the shim material that is riveted to the back of them has started coming off.