soft brake pedal after sport brake upgrade
 

Upgraded to sport brakes (all fresh rebuild) with stop tech d/s rotors.

Did the brake bleeding, RR,LR, FR & FL.

Took out a few bubbles, still a soft pedal. Did this procedure 4 times, and all rears are good, front would have a bubble and still soft pedal.

Push down slightly, release and then push again...it feels okay.

but the first initial push, it's soft....half way down then it grips.

Any suggestions? Took a 30 min ride home, calipers are not hot, rotors are obviously hot to the touch and didn't seem like any leaks.

Any help would be appreciated.

Thanks

Sounds like there's still air in the system somewhere.

Yeah. What I thought. Bleed them 4/5 times already

is the brake master cylinder on Sport pack Z's the same as base model Zs?

FSM says RR,LF,LR,RF is the sequence. You are bleeding both the inside and outside bleeders right? Each caliper has two bleed ports.

yeah I was going to call out and say you need to bleed of BOTHsides of the calipers otherwise you still have air in the system.

Correct. I'm doing both bleeders

Are you using a Motive or vacuum bleeder? If not you may need to get some more pressure and flow through the system to force the air out.
Or take it to a shop and have them "power" bleed it.

If you do a gravity bleed by opening all 8 bleeders at the same time and keep the M/C full in the process the air will remove itself,I do this on all my cars works like a charm.:tiphat:

And you don't have to use a power bleeder ,my way takes ten minutes

I would check this.

I pretty much always bleed twice after any major brake work where lines were disconnected: do an initial quick bleed (outside then inside of each caliper), go for a test drive (in the most recent case: start the process of breaking in new rotors) which will knock the air bubbles around, and then come back home and re-bleed everything again. Usually on the 2nd bleed you catch a few more bubbles that didn't come out the first time.

I'll try this! Thanks

gravity bleed is the best way, takes alittle time, and you need alot of bottles, but it works the best, dont cross contaminate old and new fluid, and it can be done alone. I used to work at Brembo NA and this was the method we were told to use

You only need ten minutes and 1 quart of your favorite brake fluid.

^yeah i know, a little time is about 10-15 mins no? lol

Yeah,give or take 20-30 seconds.:icon17:

^ i usually just run two bottles of Motul RBF 600 through it on a gravity bleed, and BS on facebook till its done LOL :P

you could have a loose zirc on a caliper too? have you lost any brake fluid since flushing?

The brake master cylinders are the same (D6010-JK02A).
The brake boosters are different:
Base = D7210-1ET1A
Sport/Nismo = D7210-1ET0A

Hoping the OP can solve his problem.

AND this is your PROBLEM! easy fix but that's the source. Since the booster on the sports z pushes more fluid and your z now isn't, that explains the lack of stopping power. Its the same idea behind electricity when you add multiple lightbulbs on one circuit and they get dimmer.

Have a lot of people going from base to a BBK actually upgraded their brake booster? I feel like this is the first time it's come up.

:iagree: very interesting that I haven't seen anything about the different brake boosters in the base and sport with regard to this upgrade...

I'm sure somebody would have mentioned it by now.

Z1 says you need a new oil line for the caliper (hardline).

I'll be getting it fixed in the next week or two. I've searched and people that upgraded never changed the booster.

Has to be a air bubble.

They talking about the stainless steal lines?

Ohhhhh lol

Just guessing myself but just from what I've read seems like a popular upgrade.

Yes there is a metal line suggested from Z1 to upgrade. Which I did.

Still soft?

this is a silly problem and thing to ask, but its a common mistake on brake swaps. Are the calipers on the wrong side? Its very easy to do and is almost always the case when my powdercoating customers have issues, although on some calipers, its not as obvious as on these. bleed screws on top.

Bleed screws are on top. Metal like installed. Just did a re-bleed 3 more times and its good to go.

Thanks for the help.

Yep. 99% of the time it just needs to be bled again. A few taps on the caliper with a rubber mallet helps get any stubborn bubbles dislodged.