help - i'm sure i've missed something

[Dons67]

when i purchased the car it had a ccp front disc conversion with new brake booster and prop valve the the standard rear drum in place

when i rebuilt the rear end i added a simple disc conversion and left everything as it was (worked great with no issues)

at this point in the story everything is fine..........

so it was time for new brakes up front and instead of leaving things normal i of course had to seize the opportunity to do it better.

i grabbed a big brake kit from ccp with c5 calipers and rotors - when adding the kit i also installed an adjustable proportioning valve in place of the old one

while installing the new valve i replaced the brake lines from master cylinder to the valve because i didn't want to add a reducer to every connection (i mention this because the new line is a smaller diameter than what was there and i'm not sure if it makes a difference or not)



i then gravity bleed the system, flushed out all the old fluid then had a friend over to do a final bleed

now i have no pedal and it pretty much goes to the floor (it is enough to stop the car but not at any speed over 10mph)

what did i miss or do wrong?


any help would be greatly appreciated!!

don

[rickpaw]

Tobin @ Kore3 may chime in, but I think your MC may be the wrong size.

[agoristmike]

Was the big brake kit actually built with your car in mind? seems odd that the lines would be a lot smaller than what was on there previously. It's also possible that they sent you the wrong lines or mc in the kit.

[Dons67]

Was the big brake kit actually built with your car in mind? seems odd that the lines would be a lot smaller than what was on there previously. It's also possible that they sent you the wrong lines or mc in the kit.

yes it was designed for a 1st gen -- the lines with the kit are fine it's the lines i ran from the master cyl to the prop valve that are smaller than what i had there before -- i didn't want to use a reducer on every fitting do i went to the auto parts store and picked up pre-made lines with the correct fittings then installed them

[Apogee]

Line size shouldn't have any noticeable impact on pedal travel, so whether you're using 1/4" or 3/16", you should be fine. There's certainly some validity to the comment regarding master cylinder size, however the most likely scenario would be that your MC from the previous kit would be too large of a bore for the C5/C6 calipers, leading to an extra high, firm pedal with low brake torque, not a low pedal. We would generally suggest a 15/16" to 1" bore master cylinder for a C5/C6 brake application with vacuum assist.

No pedal typically means you still have air in the system.

Tobin
KORE3

[Dons67]

thanks for the info - back to bleeding it is !

Line size shouldn't have any noticeable impact on pedal travel, so whether you're using 1/4" or 3/16", you should be fine. There's certainly some validity to the comment regarding master cylinder size, however the most likely scenario would be that your MC from the previous kit would be too large of a bore for the C5/C6 calipers, leading to an extra high, firm pedal with low brake torque, not a low pedal. We would generally suggest a 15/16" to 1" bore master cylinder for a C5/C6 brake application with vacuum assist.

No pedal typically means you still have air in the system.

Tobin
KORE3