What pads are you running again? Are you sure what you're feeling is just lack of initial bite and not a soft pedal? Aggressive pads don't had anything going for them for the first inch or so of pedal movement, my R16s and DTC70s both have nothing going on for them until you really put your foot in it.

 

st43s

 

ok so

test drive the car with no shims is still on the docket, but pressing the brakes indicates it's likely the same. if not, i can either try the new pads & rotors, or get the calipers rebuilt and do it all at once. new ss lines coming too.

 

What other pads do you have? ST43 is pretty aggressive and don't have initial bite like you get with lots of street pads.

 

girodisc s/s. even if they don't have inital bite, it should be stiff but not stopping, rather than being soft, correct?

could it be the surface of pad to rotor contact, i.e. if it's not even?

 

No it won't be stiff for the first inch or so of travel. After that first inch they should be very stiff.

As a test, with the car off pump the brakes about 20 times. By the end the pedal should still have 0.5-1" of free play and then should be rock solid.

 

when i pump the pedal it is stiff up top though. i realize that sounds like an air issue, but i've been bleeding and bleeding

 

No it's not an air issue. If it was an air issue the pedal wouldn't be stiff up top after you pump it.

It honestly just sounds like an aggressive pad compound to me. Unless your have to push the pedal very far to get decent stopping power or the pedal performance is getting worse over time then I don't think there's anything wrong.

 

i'll test with the other pad also - to be fair, it did not lose any pedal pressure/feel during the last track day, braked the same lap after lap with no fade. soft for a while after the track day but apparently that is common for srf

https://thebuildjournal.com/tech-gui...view-analysis/

 

Can't speak for SRF as I've never used it. I still run Motual RBF600 because it's way less. I'm either going to move to Endless or Torque RT700 next.

 

was considering endless, really good compressibility - but isn't it more expensive? i think castrol is 70/1L right now, usually ~60, i see endless at 45/0.5L, on amazon anyway

 

Yea Endless is pretty pricey as well. I'd more than likely go with Torque as it's a good bit less.

 

So another thing to note, I've notice used race pads will get a bit mushy in the initial pedal travel because the surface of the pad can crack from heat and I think that makes it compressible, so that may also be what you're feeling.

Like the yellow car I took to the 1/2 mile, the pads are roached and made a really soft/long pedal. New pads fixed it.

With the ST43's I've noticed what you're describing. Try putting your street pads in and see how it feels.

 

gotcha.

so i pulled the shims, did a mini bleed, and tightened the lines - the front pass line had a very small leak. the pedal feels firmer but still has that squish when i push hard. im going to try the street pads to see how much of that goes away

 

swapped in the s/s pads and the brakes are pretty darn firm, even with the ti shims on them - so, i guess it was a combination of a few things, the pads, line leaking a little.