Soft Brake Pedal

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  #106  
Old 02-03-2011, 09:14 AM
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G35 sedan w/ too much money in mods
Yep, just filled it full and noticed a difference. May not work for everyone but for $4 for the brake fluid I think it's worth a try.
 
  #107  
Old 02-03-2011, 01:37 PM
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Can you slowly remove a bit at a time to see how much you can take out w/o losing the feel? If your pads are 1/2+ worn, when you replace them, it's going to overfill the container when you push the pistons back in.
 
  #108  
Old 02-03-2011, 01:43 PM
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G35 sedan w/ too much money in mods
Jeff are you asking me if that's possible or if I will do it myself and report back? I can tell you that last week I used a baster and removed enough fluid to get the level just above the full line and the feel was noticeably softer than with the level where it is now. Not a huge difference but enough to feel. I would have to assume that as you remove fluid from a full MC the feel would get softer the more you removed based on my experience.

As far as the level, you're absolutely correct that someone with half worn pads wouldn't want to fill it completely unless they are willing to extract a good amount on their next brake job. For me it isn't an issue as my pads were brand new at the time.
 
  #109  
Old 02-03-2011, 01:47 PM
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I was asking if you'd be willing to take a bit out and observe the feel but you've pretty much answered my question thanks. I might try this now. I might have some fluid left over from my 06 Z brake swap.
 
  #110  
Old 02-03-2011, 09:24 PM
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I can't see how the fluid level in the reservoir would have any effect on the pedal feel.
 
  #111  
Old 02-04-2011, 08:40 AM
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Originally Posted by Dudefish
I can't see how the fluid level in the reservoir would have any effect on the pedal feel.
I can't either...but at this point ill try anything
 
  #112  
Old 02-04-2011, 09:02 AM
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G35 sedan w/ too much money in mods
I can't explain it but I can say it worked for me. Like I said earlier it's worth $3-4 to try it to see. Worst case scenario it doesn't do anything and you're only out a couple of bucks.
 
  #113  
Old 02-06-2011, 05:42 PM
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well I think I figured out my problem today.

I was working on the car again and planning on bleeding the brakes for the 4th time (in accordance with the service manual) and I noticed on my passenger front caliper the clip that pushes the bakes back was jammed in on one side. so instead of slightly removing it from the rotor, it was pushing against the pad.

got some pliers and pulled it out and bent it back the way it was supposed to be going. bled it one more time for the hell of it and just did some test pumps in the car and it seems a lot better.

car is still in the air (on jackstands) so I can't say its fixed yet but it sure as hell seems like that would be causing my issue.
 
  #114  
Old 03-17-2011, 10:12 PM
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Just to update. Filled my mc to the max...no change.
 
  #115  
Old 04-16-2011, 05:54 PM
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I just read this thread after flushing my brakes with a motive bleeder (at ~8-10 psi if you are curious) and used prestone DOT 3 fluid.

My pedal was sometimes soft before, but the fluid was so old it just didn't have a good pedal at any time (05 G/93K/OEM fluid). BTW, I'll be flushing one every year or two, my old fluid was brown, and the initial bleed from all the calipers had this white junk float out followed by bits of black for a second or to. Yeesh.

Now it's noticeably soft on the first push, then firms after. It feels great after. Basically, the issue the OP has.

I bled RR, RL, FL, FR. I know this isn't the FSM procedure but I could only get two wheels in the air at time. I also didn't not disconnect the VDC/neg terminal.

My 02 Altima had this problem, but reverse: It would be very soft but occasionally get firm.

I will be living with it for now and watching my fluid level to make sure I'm not leaking somewhere and introducing air.

EDIT/UPDATE: For the first time tonight the car had good pedal, this was the third or so driver after the above bleeding was done. It was significantly cooler than it has been and the pedal was not soft for one time the whole night (~30 miles of driving). I may try bleeding again at my next oil change. There were a few tiny bubble that came out of the rear calipers near the end of each flush.

Vacuum bleeders: I don't recommend guys using these continue to do so. I know there a fellow a few posts up who using teflon on his bleeders thread for a better seal but the theory behind it is that air can still be sucked in. I think the two-person method or powerbleeding is the only way to ensure you won't introduce more air into the brake system.
 

Last edited by AuAltima3.5; 04-16-2011 at 10:31 PM. Reason: Update
  #116  
Old 04-16-2011, 07:31 PM
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G35 sedan w/ too much money in mods
Weird you bumped this thread today, I was heading in here to update my posts. Seems like the full MC was a temporary solution. My pedal has gotten softer and the MC's still full.
 
  #117  
Old 04-18-2011, 12:02 AM
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Has anyone every changed their mc? Its too expensive of a part to do on a hunch, but other forums I am on suggest this as the primary culprit. However, it's a $200+ part so I am wondering if anyone has changed it due to a soft pedal and noticed improvement?


Im really sick of double pumping when I come off the highway to get a good pedal.
 
  #118  
Old 04-18-2011, 02:28 PM
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I changed the MC in my old Nissan Z32, but it didn't really make any difference in pedal feel. I'm not sure changing it out will really solve the problem. But you could try bench bleeding the MC again and then re-bleeding the system.
 
  #119  
Old 04-19-2011, 08:05 AM
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My dealer did replace my MC under warranty (or, at least they told me they did) to try to improve the pedal. It didn't help. I still feel like it's a MC issue. It's ridiculous, really. My wife's minivan has a far superior pedal to my G35.
 
  #120  
Old 04-19-2011, 08:08 AM
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Originally Posted by G35fromPA
I changed the MC in my old Nissan Z32, but it didn't really make any difference in pedal feel. I'm not sure changing it out will really solve the problem. But you could try bench bleeding the MC again and then re-bleeding the system.

But was there an issue with your brakes before? The thinking is there is a defect in the MC allowing fluid to leak past the internal seals.

I've bled gallons through the system. Nothing makes a difference. I'm at the point where i'd like to start changing components but really don't want to throw random $$$ unless i have a good idea of the cause.


I'm very familiar with brake systems (installng custom brake kits, reflaring lines, installing different MC's to match calipers, etc), but this one has me puzzled.


I mean at this point, i'm so used to it it doesn't really matter
 


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