drivinhard

Anybody gonna be at RA this weekend that has a Tech 2 I can borrow?

sperkins

No luck I guess with the Tech 2. Did the Motive bleeder help at all?

BTW - How did the day go in TTA?

gkmccready

Geez. Are Tech2s really $3600? Ouch.

drivinhard

Scott, I did a full bleed with the motive. No change. Did another bleed, and running the ABS pump w/ the car on the lift (again), no change. Replaced the master last night @ midnight, full bleed again, cycle ABS pump again, no change. I am really stumped at this point.

Despite that (really mushy pedal, requiring lots of left foot confidence pumps before hard braking), I managed to barely nip Jason today in the friggin blazing heat, with a 1:36 flat on the Ho-Ho A's. Gotta love the A6's, it's like putting on a superman suit. I am thinking 275's are the way to go, I would like to use the spare pts I have for real brakes.

MySR71

What kind of brake trouble? Soft or low pedal which doesn't pump up?

exracer28

I will have mine at Barber with the BMW club on the 22/23 and then back to Barber for the SCCA event over labor day. White C6 #36.

I assume you are having brake problems? After bleeding but before driving do you get a good pedal? Have you checked the PSI as each caliper?

John

sperkins

1:36 flat! Holy crap man that's crazy. I remember last year people said that TTA would be in the 35's very soon, but I didn't believe it. Congratulations buddy. Job well done.
I'm guessing you didn't tell Jason about the ballast you added to his car huh?

I'm thinking like you said yesterday that a tech 2 may be required to purge the front. You may want to call Jason at Balanced Performance. I'm pretty sure he has one. As a matter of fact, I remember seeing his trailer in the infield paddock yesterday. I'd run over there first thing in the morning and see if he can help.

drivinhard

Pedal is soft up top, and never really firm or confident, and long. Very hard to heel/toe with it that low, plus it's messes with your head on a high speed track like RA.

Calipers are all "new" (swapped from my parts Z06, street car, so I know they aren't spread) no change there. car has SS lines, pads are good (not tapered), master is known good (also from the spare car), the only way I can cycle the ABS pump is using traction control on the lift (running the rear wheels). I've done a full motive pressure flush.

any other ideas? I am not a pro with the circuits/valves inside the pump, so I don't know what valves are opening by using the TC on the rear wheels on the lift.

drivinhard

Jason has not yet noticed the sakcrete that is now in his frame rails

I dunno how much faster the A's are than the R's, being skinnier, but jason is a heck of a driver, so if you can beat him, you are doing good. I think he will be a killer w2w guy when he gets that far. I would not want to have to race against him.

re: 35's, I think it's more than doable. cool weather is worth a lot of time, and I am still sorting the balance of the car, I am not happy with it fully yet.

MySR71

I was going to say spread calipers but it sounds like you have taken care of that. I had a low pedal which wouldn't pump up and it took me awhile to figure out it was the calipers.

sperkins

OK I'll bite. What exactly is a spread caliper?

MySR71

The caliper had lost too much of its stiffness/strength. So when you pushed on the brakes, the sides of the caliper would flex and result in a low pedal before they would firm up. Pushing on the brakes multiple times quickly, ie, pumping the brakes, would not make for a firm and high brake pedal either. I replaced the calipers and the problem went away.

Based on my reading, if there is air in the system, pumping the brakes would give a firm and high pedal.

drivinhard

I am going to try opening the bleeders on BOTH ends of a circuit (LF/RR, etc) while running the car's traction control on the lift. I did not have enough pedal to get into the ABS anytime during the weekend (I don't try to, but every now and then you will just trying to threshold brake).

Of course, the A6's have so much friggin grip, it is hard to overpower them. I have used the Wilwood "A" compound in the past, and it would have been nice to have some stiff 4 or 6 pots up front with some "A" pads, they make some serious torque.

exracer28

Have you tried an old school bleed where you have someone in the car and have him/her press the brake down and then you oped the bleeder one at a time? I have tried other methods and found that to work the best. I also use different color fluid.

I have also had bad brake lines that were coming apart internally.

sperkins

You're such a perfectionist.

I had a blast Friday. See you at the track.

drivinhard

BTW as a follow-up to this...this worked. Previously just opening 1 end (either front or rear) didn't work. I put positive pressure on it from the motive, opened LF/RR (and vice versa) and ran the TC/ABS pump, pedal returned to normal. It took both ends open, FYI if you run into the same problem.

T'was nice to have brakes at VIR.

sperkins

Thanks for posting that info Mark. I'm sure I'll need it someday.