haaaa ..

ive got the same issue ..

i always thought it was so i couldnt lock the brakes up and slide .
or part of the abs ..

idk ..

im subscribing ...

 

Mine turned out to be a case of knockback common to the larger big brake kits. I've had to explain it to a corvette owner so knockback isn't G35 specific.

That said, your problem does not sound like knockback in the least respect. Seems your going in the correct direction with the master cylinder. When I took the G into Infiniti for a warentee look over they wouldn't touch it with the BBK on. Once I took it off they had no gripes looking at it. So I'd say even if you did some of your own work the stealership should look at it if it is stock.

One thing I'd consider. Once 'pumped up' and given the time to go soft may mean a bubble of air has had time to expand the brake pads away from the rotor. It's reasonable to me that this expansion would happen gradually. Check the individual pads to see if they rattle or are loose against the rotor when stoped and a few minutes after you pump them up. If one corner of the car is loose you norrowed down the problem (bleed, and bleed again).

I've read some complaining that the ABS can hold air like a high point in a tube. One suggestion I saw was to disable the ABS (fuse or disconnect battery) and flush the fluid.

As for the brace. I own it but never put it in because my MC is different from every other G. Mine is ~3.5" most others ar ~5".

Hope that helped.

 

Well, I'm sure it's not knock back. Reason being if I am in traffic, and pump upmthe pedal, and then creep forward 10 feet and get on the brakes again, the pedal is soft again. Unless the pads are kicking out in 2-3 revolutions, I'm convinced it's not knock back.

Ive heard some theories on other forums that this situation is caused by a failed seal internal to the mc. Not convinced yet to change it out.

So anyone new have anything to add?

 

i did my brakes, (rotors/pads) about a week ago, and i'm thinking that in the process of pushing the pistons in and removing the excess brake fluid, (dash lights had lite up because of low brake fluid caused by worn out brakes) i must have pushed out a bubble or something because my car doesn't do it anymore. i didn't flush out the fluid either, just pumped it out from the MC.

or maybe that brakes were soooo toast that the MC couldn't pump out enough fluid on the first pedal press to get a grip? (52k miles on once turned rotors, and worn down pads) i dunno....

all i know is, it's fixed.

 

That's good news. I need to do another bleed soon. Maybe I'll try a reverse bleed or something

 

From my personal experiences:

- I owned a 2003 350z Touring (non-brembo) 6spd and the braking was excellent, instant bite. Car only had 12,000 miles when I got it.

- I test drove a 2004 G35 coupe (brembo) 6spd and the braking was even better. Car had 21,000 miles.

- I own/drive a 2006 G35 coupe (non-brembo) 6spd and the braking was meh. Car only had 24,000 miles on it. Granted, I didn't replace the pads/rotors with OEM but some aftermarket pads/rotors and again, meh. The next time around, I'm going to go with OEM pads/rotors and see if I can get back the instant "bite" even though I never had it on this particularly car.

I put blame on the previous owner and his driving habits for the premature brake wear. However, I put blame on myself by putting on aftermarket parts on before verifying the braking ability of the stock OEM setup.

A bandage to the problem as some have mentioned, I "pre-brake" by pushing on the brake pedal a good inch or two prior to heavy braking. This seems to help with the soft feel.

I don't know what to do next, maybe try that Stillen MC bracket... a lot of money to shell out on something unsure, however.

My 2 cents.

 

...

 

Has anyone used the master cylinder stiffner from Stillen? For $150 it might be worth a shot.

http://www.stillen.com/product.asp?i...NITI&model=G35 4DR

The brakes on my 03.5 have had a mushy pedal feel since i bought it. I replaced the front and rear pads and rotors and it only improved slightly. I plan to change the brake fluid soon to see if it helps.

 

Another brake bleed didn't help me. Gonna try making a pressure bleeder and do it that way.

I have spoken to a few very knowedgeable brake guys on other forums who have suggested the cause as being the master cylinder. However, that's a very expensive and pita part to replace without being sure.

I also double pump on braking...one pump to take out the "slack" and the next pump to give that instant brake bite. 2nd pump braking is awesome...But that first pump is just too mushy. I am on 2nd set of oem pads and rotors and maybe 5-6 bleed jobs.

Btw, infiniti told me "brakes seem normal" even after telling them they got more responsive after intitial pump

 

has anyone else had any luck fixing the issue.....I have the exact same issue. I am well overdue for new brake pads :/ and am going to get some new OEM pads since I just do "normal" daily street driving and have OEM brake system for '05. I am also going to flush the lines and replace the fluid and see if I have any luck with that.....

 

Not yet...i still have issue.

 

Subscribed. I have this issue to a T on my '03 with all stock brake parts. I guess I'll start the process of trying to narrow it down.

 

I have the same problem.. The pedal goes all the way to the floor sometimes.. Id have to pump the brakes twice.. Im thinking id have to bleed the brakes again.. i have ss lines and motul brake fluid..

 

This seems to be a very common issue across the board. I think I might buy the Stillen MC brace and see if it works. I'm probably going back to 05 OEM pads when my Hawks wear out as well.

 

I know exactly that feeling you are talking about. My G does it, so do my other cars. I wouldn't say that's normal. It seems to only happen after my G35 has hit 40k miles.

I trust that you do not have air in your braking system. You are definitely intelligent enough to know whether you do or not.

Switching to slotted rotors helped with that significantly. I cannot assume why slotted rotors reduce the soft brake initial pedal, as I do not have scientific data to justify any claims. However, the advertised functions of rotor slots seem to be doing their job, possibly releasing gassing that occurs during that initial hard brake after a cool down period.