Geoff17

I have a 2006 C6 Z06 fitted front and rear with the Stop Tech BBK. I run Hawk DTC70's in the front and 60's in the rear. When the BBBK's were first installed the braking was exceptional. The initial bite was huge and the pedal was always firm and high.

After each event I bleed the brakes and about every 3rd event I flush the system. I use Motul 600. After about 2 or 3 events the pedal became soft. The stopping was still good but the pedal was much lower. I have gotten in the habit of doing 1 pump prior to my braking zone. This brings the pedal up a little and reduces some of the softness.

I have bleed the brakes using the 2 person method, the Motive power bleeder (20-23psi) and I even had the dealer bleed them (believe it or not he is a very good mechanic and former club racing champion).

Every time I bleed them there is air in the system but typically only a couple of very small bubbles. I do not use previously opened containers of brake fluid so I don't think moisture is the problem.

Typically I get about 2 laps in and then the softness returns.

My pads and rotors were broken in properly and I essentially do not drive the car except at the track.

This is my first year tracking the car so I am sure I am not as aggressive as many of you. After 10 sessions my front pads had about 40% left, my front rotors are covered with heat checks but I hang a nail yet so they are okay. I changed the front pads to see if this would help but the result was the same.

I have only run Summit Point (my best times are 1:23) and VIR full (my best times are 2:20-only 2 events here so far-looking for 2:15 come the Chin Nov event!). I know I use the ABS a lot-I am working on threshold braking. I believe I am smooth in my pedal application.

Any ideas would be appreciated.

Geoff

Sidney004

The air in the system sounds very suspicious. Are the air bubbles visable on every caliper or only one? It sounds like a minute leak somewhere in the system.

Geoff17

Air is typically visable in all calipers. If it is a leak it is very small becuase I am not losing any significant amount of fluid. How do you check for this?

Thanks for your reply

Geoff

John Shiels

Leak could be very small so check carefully after you use it. I had a slbow into my Wilwood that was ever so slight due to me not tightening it. Look and feel for any fluid. Ask Jeff Ritter or LGM if you bought them there also.

Sidney004

If you are seeing air in all the calipers after just a few laps, it is probably a very minute leak. The chance of boiling the rear brake fluid is nil. I would start with checking all the line connections after the master cylinder, especially all lines associated with the BBK retrofit. Hopefully, there are better mechanics than me that will chime in. It does not take more than a microscopic leak with 600 PSI of line pressure to get air in the system.

Geoff17

Thanks John and Sydney-I don't know why I didn't think of a minute leakage-I will need to check this out. That sounds like the logical issue.

Thanks, Geoff

96CollectorSport

The air may be in your ABS system, sometimes if you have air in the system or boil the fluid the air will work it's way into the ABS pump and the only way to bleed out the whole system is with a Tech 2, that will activate the ABS pump and individual silenoids as you are bleeding. Hopefully the little bubbles are seeing will all work there way out and you will return to a solid pedal.

0Louis @ LG Motorsports

Check the wheel bearings as well. I see a SMALL amount of air every bleed, but it is because the seal between the bleeder taper and the caliper itself. I can assure you there are no leaks, on the WC car, yet I still see a smallll amount of air. If you close the bleeder and just crack it ever so slightly, you cannot see the bubbles.

If you clean every fitting off, and see no "sweating" around any line, you should be fine in regards to that aspect.

Does the soft pedal come after a turn, after a straight? any sequence that it seems to return to?

V8 Juice

Geoff,
Alas, using a Tech 2 and clear bleeder line at the nipple valves is the only way to really purge the whole system and see what's coming out - if you don't want to spend the $5K for the Tech 2 you are reduced to what I do when the pedal doesn't feel right.....pay Tony!! BTW, I believe your post meant to say you "DON"T" get any nail hangs yet. Sorry for all the grief, really spoils the day if the brakes don't feel right.

Geoff17

Thanks for all the replys (except for that wise guy Art AKA V8 Juice)-I am going to follow up with them next week.

Art, for an darn accountant you are pretty picky in the grammar department. I wouldn't have to pay Tony if you would build your garage and provide me with a decent place to work on my car!!!

Geoff