My Megans do the exact same. I have a lot of pedal travel after a hard turn, then it is firm after I pump it once. Kinda scary on the track!

 

^ probably knock back

 

^Whats that? How to fix?

 

There's some good info on Stoptech's site:
http://www.stoptech.com/tech_info/wp_knockback.shtml

 

I don't know **** about wheel bearings, so can we buy new front hub and bearing assemblies? How much? Where? ahhhhh

 

My discussions with ppl on this site as well as a few shops leads me to believe this issue really isn't worth the trouble to correct. It becomes just another part of life for many people with BBKs and big rotors - after a while you learn to tap the pedal lightly before you need to make a hard stop to get the pads back close to the rotor.

 

Have someone press your pedal while you're looking at your master cylinder under the hood. I couldn't believe my eyes the first time I saw this on my 300zx. Since then I have made my own brackets and have bought Stillen's unit for the G and Zs. They are well worth their weight in gold. If you can fabricate something for less, by all means, DO IT! The pedal firms up so drastically. In fact, from my own tests, the Master Cylinder Support is more noticable with stock rubber lines than installing steel braided lines. Of course, after the MC Support you should be installing the Steel Braided Lines because that's your weakest link now.

Its funny how people always suggest the steel lines as part of the upgrade with upgraded rotors and pads. The support gives way more confidence by itself on stock rotors, pads, and lines than the three combined! Add them together and it is a completely different brake feel.

You should try it before you discount them.

 

What's the verdict on this idea? does it work?

From the external design of the ABS module, I would expect that to work, however, I have no clue what is on the inside and what rout the fluid must take.

Wish I could see through objects

Adrian

 

I can't get any tricks to work. I'm going to take it to Infiniti and get them to plug it into what ever they need to to cycle the ABS while bleeding the system.

 

Please let us know if that fixes it... and how much it costs

http://www.aa1car.com/library/abs_bleeding.htm

Adrian

 

any updates?

 

Oh FYI, I took the car to Nissan and they said they can't do anything that'll correct the problem beyond what I did. Then I called up Infiniti and they said the same.

I did some driving around to try to pin point the problem and turns out I don't even need to be moving for it to happen.

I sat in the garage applied the brake a few times until it firmed up, turned the wheel full lock to either direction, then applied the brake again and it was soft. So I'm thinking suspension problem. After the holidays I'll see about rebuilding or ordering new wheel hubs. I haven't started to search yet so any links to threads or manufactures websites would be great.

 

I'm in the same exact boat as you. Never had the problem with my BBK till I installed my rear extended studs.

I'm working with Stoptech right now on an issue I have with one of my rear calipers/pistons but after reading this thread, I think it might be something else now. To make a long story short, one thing I did was remove one of the rear hub nut....I think I'm going to order a full set of bearings all around and give that a whirl.

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Glad I found this thread. I have the same exact problem.

This is witch STOCK '06 brakes. Haven't done a thing to them.

Pedal just feels soft. Wasn't always like this. I distinctly remember the pedal being firm and then all the sudden getting mushy. I can still stop very well, but i find that a quick double pump when i start to brake firms up the pedal and makes the response much better.

It even does it from a dead stop. I don't need to be moving. I can pump the pedal a few times and it firms right up...but wait a min or so and it gets soft again.

I've bled the brakes..no difference. Gave the front a new set of rotors and pads (it needed it) and no difference. Rear brakes look fine. Visually, the brake hoses look fine and do not expand when i press the pedal hard.

With the car running, i can put all my weight on the pedal and basically push it to the floor. But the car does stop fine, it just feels soft. I've driven loaner cars and the first time i press the pedal, i almost go through the windshield because the response is so instant.

I'm no stranger to brake bleeding or brake maintainence, but at this point, i would suspect the MC of being faulty. However, in most cars i've worked on, the pedal still remained slightly soft when the car is turned off. With my G35, the pedal pumps up hard as a rock when it's off suggesting no internal leak. That leads me to the booster, but boosters provide assist. Most faulty boosters i've seen make the pedal hard as a rock..not excessively soft. Prob is, the response is poor when the pedal is soft, so i don't think it's the booster either. I'd bet on the MC. I'm still under warranty for 3 more months though, but i'm weary of taking it in when i've done my own brake work up front and bled the brakes on my own.

How is it to replace an MC on these cars?? I can bench bleed an MC, but what do i need to do to cycle the ABS to bleed the lines? Any other sort of backyard trick i can use? Otherwise i'd have to do the MC swap myself and then tow it to the dealer to bleed.


This thread is nearly a year old...so hopefully someone has new info?? or Updates? I have googled this prob, and it seems to be a common problem. However, in other threads, some have mentioned the Stillen Master Cylinder brace has fixed it. Seems the MC dives during hard braking?? Anyone else have any input on this? The brace is $135, and if it does fix this issue i'll order it up ASAP, but i don't want to waste the cash if it's not. Seems like a pretty good factory defect if an aftermarket brace cures the prob

https://g35driver.com/forums/brakes-...r-brace-2.html

I'm getting sick of double pumping my brakes when i need to slow down fast.

 

i hope someone else has input on this because i have the same issue on my G. Hope someone else out there has the answer!