ShahulX

Did some research online here, so I apologize if this has been covered before..

Got a 350Z 08 Nismo about 2 months ago... upgraded tires to R888 and brake pads to Carbotech Xp12 on the stock Brembo calipers. I did add goodridge steel braided brake lines and stoptech brake fluid STR-660 with the disclamer... For Racing Applications. DOT 4 automotive brake fluid Dry Boiling Point: 622°F Wet Boiling Point: 404°F Min. Wet Boiling Point: 383°F

All done at a dealer..

Regardless, on a 45 degree and blustery track day yesterday, I lost all brake pedal feel after about 6-7 laps.. I mean pedal to the floor. It was very strong for those 1st few laps.. Shenedoah circuit at summit is a brake heavy track

side note, did also notice some coolant leak? no correlation i believe?

rancor

Boiled your brake fluid ?

MicVelo

Are you asking a question of just passing along the experience?

Dropped pedal is a relatively common problem on Z's, particularly the HRs using internal concentric slave (CSC). There can be a variety of reasons, one of which is the culprit with higher probability: air gaps in the hydraulic system.

Re-bleeding - recommend using a power bleeder like the Motiv - usually clears this up. If not, then there's a good chance the slave cylinder is bad. This isn't unusual if your CSC has never been upgraded. If that turns out to be the case, don't bother with a Nissan OEM CSC, go straight for the Z-Speed Performance HD CSC. Should clear that up for good.

Second possibility: bad pedal actuator connecting the stock clutch pedal to the clutch master. Remedy there is making sure it's connected properly, properly adjusted OR aftermarket clutch pedal (RJM) to replace stock pedal.

Good luck!

travlee

iTrader: (8)

Mic.... he is talking brake pedal, not clutch

turboed350z

Just be glad mic didnt say "op your brake pedals are acting up because you didnt attend driving school." Lol

MicVelo

Whuuuuuuups....

Hmmmm, maybe I'd best demand a refund from that online Evaelyn Wuudhead sped reddin' course I took.

Oh well, OP, now you'll know what it is when the clutch pedal sticks.

But, I'm only half wrong as symptoms still seem to be hydraulic in nature.

Tochigi_236

Check your pm.

ShahulX

That's what I was wondering.. I've never used stop tech fluid.. I usually use motul rbf600 in past cars (Boxster spyder , Gtr, exige, evos) .. But this looked fine by specs and stop tech is a well known company) . Im wondering if maybe someone had issues with that fluid, similar situation with the stock brembos?

I did drive home after I was there for an hour.. After cooling off there was brake pressure so I could drive the hour and half home... Think it was the fluid?

rancor

I have never boiled my brake fluid and also dont have the brembos so no first hand experience. It seems like the simplest answer but some more experienced drivers that track the Z might be more help.

If the pedal didn't feel as hard as it originally did after cooling off I would still think its air in the system. I wonder if the dealer didn't fully flush the system and you still had some old fluid in the calipers.

ShahulX

that would be unfortunate.. i guess im buying some new fluid and trying again...see what happens now

rotors are the only thing i didnt do... thoughts??

ShahulX

while im no mechanic... i kinda know about cars,in a rudimentary way... but the coolant shouldnt have an issue right? im hoping that was just overflow

dkmura

iTrader: (64)

One item not mentioned is pad transfer and proper bed-in with new brake pads. With heavy braking on a cold day, the proper film may not have formed on the surface of the used rotors.

ShahulX

I did bed them in a few days prior using the instructions given by carbotech... Although it may not have been perfect and on stock pre used rotors, may not have been ideal.. Im not sure that would affect the brake pedal to the floor situation... It does affect the initial bite and overall braking capabilities, but not sure it correlated to the pedal loss pressure. Maybe I'm wrong... Was debating rotors... Best for heavy track use for the 350z brembos?

Blurvision

iTrader: (4)

You have air in the system or the master has failed. No fluid leaks I would assume? Your brake setup you described should work just fine, Shenandoah inst that hard on brakes.

ShahulX

kinda what i figured.. but your decisive response helps confirm my suspicions. I'll get the fluid redone and check the brake master cyl. ty

Blurvision

iTrader: (4)

Just to add, a master cyl can fail internally leaking air into the system but not leaking fluid. They are pretty cheap to replace, might be worth some preventative maintenance.

ShahulX

Ok, hopefully wasnt gonna cost an arm and leg... i'm taking to a nissan shop this time, just in case

Thank you again!

ShahulX

OK so the Nissan dealer is telling me there was too much brake fluid? And that's why the pedal was going to the floor on the track after it heated up? Is that possible? Doesn't sound right

rancor

That doesn't sound right. Maybe overfilling could damage the master cylinder but it would be cheaper to try bleeding first.

ShahulX

Man.. I dont know what to do at this point.