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Has anyone actually fixed their soft brake pedal feel?

  • No, Never noticed a problem

    Votes: 18 52.9%
  • No, Have the problem but haven't attempted a fix.

    Votes: 3 8.8%
  • No, Have the problem but fixes were unsuccessful

    Votes: 3 8.8%
  • YES, I conquered the soft brake pedal!

    Votes: 10 29.4%
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Discussion Starter · #1 · (Edited)
I read lots of posts about people having a soft and spongy pedal. I have the problem on a 2002 ZO6. Just changed to goodrich steel braided lines with AN fittings... Hardly any change in the pedal feel. Have bleed the system using the two man system about 4 times, basically no real change anytime.

I'm beggining to wonder if I should change the master cylinder, the brake booster or something else???

I was using ate super blue fluid, but just changed to motul 600 during the last bleed, napa rotors, pfc z rated pads. The car sees some daily driving and 6-8 trackdays a year.

Basically the pedal is soft, you can push it in a long way before it actually goes to lockup(abs). On bleeds, I can hold it in on modertly hard pressure, as soon as the bleeder is cracked the pedal goes to the floor, the problem is that additional pedal travel is only 1-2 inches,,, basically very little.

So, if I put on a smaller brake booster, would that help the feeling, or maybe my booster is bad and I can get a new one,,, any thoughts? I don't think bleeding is the issue, but maybe a power bleeder and the tech tool method might help?

Has anyone actually ever fixed their soft feeling?
 

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I think this might be a C5 thing. Pedal feel sux, but the brakes still work like they should. I'd be interested to know what others say. If there is an easy fix to improve brake pedal feel I'm all ears.
 

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jrummi said:
I read lots of posts about people having a soft and spongy pedal. I have the problem on a 2002 ZO6. Just changed to goodrich steel braided lines with AN fittings... Hardly any change in the pedal feel. Have bleed the system using the two man system about 4 times, basically no real change anytime.

I'm beggining to wonder if I should change the master cylinder, the brake booster or something else???

I was using ate super blue fluid, but just changed to motul 600 during the last bleed, napa rotors, pfc z rated pads. The car sees some daily driving and 6-8 trackdays a year.

Basically the pedal is soft, you can push it in a long way before it actually goes to lockup(abs). On bleeds, I can hold it in on modertly hard pressure, as soon as the bleeder is cracked the pedal goes to the floor, the problem is that additional pedal travel is only 1-2 inches,,, basically very little.

So, if I put on a smaller brake booster, would that help the feeling, or maybe my booster is bad and I can get a new one,,, any thoughts? I don't think bleeding is the issue, but maybe a power bleeder and the tech tool method might help?

Has anyone actually ever fixed their soft feeling?
Yes. Baer's 4-piston Alcon calipers front and rear, 14" rotors, with SS Goodridge lines, and Motul SRF hi-temp fluids... pedal feel is rock solid and the Beast stops on a dime with a nickel and four cents change...
 

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Its the high quality (Alcon, AP, Brembo, PFC) non-floating calipers. With the booster I'm sure the car has a rigid enough pedal mount (with non-assisted race car brakes, a rigid pedal is very important). The SS line a little.

I'll bet those Alcons also have a good Hawke, Ferodo, or PFC pad.

The Wilwoods, Sierras, are ok. Their also US Brake with an interesting design. The open bridges from Outlaw and Wilwood are non-starters on asphalt.

With the SS lines, very low rotor runout, aligned calipers that aren't binding, and good pads, the floating system can work ok. Many oval classes, including the NASCAR late models, require the GM floating brakes (off an Impala or Malibu).
 

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I have the goodrich lines with ATE blue my pedal is fine :-? ,then again I never had a problem to begin with,it just feels even better now(it is firmer than before) :mug:
 

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Goodridge SS lines with Motul600 fluids, cross drilled/slotted rotors and Hawk HPS pads. My pedal feels much firmer than stock and i have minimal brake fade.

Dave
 

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I step on my brakes more than a eighth inch with more than five pounds. I am peeling my face off the windshield.

Jrummi, you're brakes need to bleed each individually using LS1edit. You probably have air in the line(s) or reservoir.
 

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Grim Reaper said:
Jrummi, you're brakes need to bleed each individually using LS1edit. You probably have air in the line(s) or reservoir.
You mean Tech II? LS1Edit doesn't have any provisions for the braking system.
 

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ScDFACHE said:
Yes. Baer's 4-piston Alcon calipers front and rear, 14" rotors, with SS Goodridge lines, and Motul SRF hi-temp fluids... pedal feel is rock solid and the Beast stops on a dime with a nickel and four cents change...
For the low, low price of...... :lol:

Really, the killer on those kind of braking systems is the consumables. How much are replacement rotors for those bad boys?
 

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You could have air in the master cylinder. Bleed that first.

Another possibility is tapered pads. If you do DE events you probably have tapered pads. The caliper has to deflect enough to get the pad friction surface flat to the rotor. I think this would be apparent if you had a solid pedal with the engine off (no boost) and a spongy pedal with the engine running.

I think Dmtnt (?) had a bad mastercylinder or booster some time back that gave him a spongy pedal.
 

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I've had the best luck just using new Motul fluid, Goodridge lines, Carbotech brakes and doing a nice slow gravity bleed until all the air is out. Start on the RR, then do the RF, then LR, then LF. Put full pads on there, good rotors and ensure the calipers aren't old and spread out. The stock calipers tend to spread over time. I replace mine twice a year (I do about 10-12 races/DE events per year). It's a fairly cheap insurance policy. You can get new calipers for about $105 each.

Try that and I'll bet your pedal feel will be what you want. If not, then try the expensive fixes.
 

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I meant techII. The system actually holds four bottles of Motul600. Learned this other day. There is a reserve somewhere in the system as well. Did not know that either.
 

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Jrummi, Go see John Best at West Coast Corvette. He has a Tech 2 and will fulsh and bleed them properly. He stock the Motul fluid as well. Cost with an oil change and your oil is under $90.

Pad taper makes a big difference. Sub Driver posted once that he switches the pads after every so many sessions. I tried this and noticed and improvement.

I had Alcons on another car and the fell is outstanding compared to the PBRs we have. I do believe the Alcons inspire more confidence. I beive they feel like they brake quicker as you don't have to push as far on the pedal. Not so sure they really do as you are limited by the tires. I would love to have a set of Alcons as one suggested, but can't bring myself to spend the money on them.

BTW the PFC Z rated pads do not bite as well IMO as some others when cold, they seam to need some temp to get them working. Try the Carbotechs or Hawk HP + for a street / track set-up. Dedicated track I have had good luck with the PFC 01's but the cost is extreme. I think the Carbotechs are the best value at form vendoer PFYC.com. Brian will set you up with the pads you need to the type of driving you do.

Not sure about the confidence factor on the LGM Wilwoods........Maybe someone will chine in. Most report no pad taper but few comment on the feel compared to stock. Are they right there, right now?, which pads F/R do you like with these?
 

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Grim Reaper said:
I step on my brakes more than a eighth inch with more than five pounds. I am peeling my face off the windshield.

Jrummi, you're brakes need to bleed each individually using LS1edit. You probably have air in the line(s) or reservoir.
yehp. mine was soft last wk and bleed them at each caliper-now I BARELY tap on the brake and I am STOPPING!
 

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The problem could be that your master cylinder or abs system injested some air and now needs to be bench bled (a regular bleed job with one man on the peddle and one man on the bleeder probably won't take care of it). Your best bet would be to hook it up to a tech II and run it throught the automated bleed process.

My pedal feel has always been rock solid in my Z... Step on the brake a little bit and your eyeballs feel like their being sucked out of your head.
 

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I think the feel of the Z06 brakes is due to the heavy assist built in. Others have mentioned that you just touch the pedal and the car stops.At first I kind of liked this but as I have driven other cars(especialy on the track) I am not so sure anymore. Most race cars have a very firm pedal(the harder you push the more you slow down) and it took awhile to get used to it while trying not to crash! I added a Boxster S to the Z last year and the brake feel could not be more different. As I put more miles on the Boxster I think Porsche might be right, though I want to be clear that both cars have great brakes! Porsche got it wrong on the Cayenne however, the brakes work great but talk about overboosted(same with the throttle, very hard to drive smoothly with these electronic controls).
 

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UstaB-GS549 said:
I think Dmtnt (?) had a bad mastercylinder or booster some time back that gave him a spongy pedal.
Just saw this. Here's the story:

Was at the track about a year ago running the Sebring short course. Absolutely brutal on brakes since there aren't any really long straights to give them a chance to cool. Anyway, after a couple of sessions, found my brake pedal travel got really long. Car still stopped fine, but had lots of travel. Bled the brakes thoroughly, no help. Switched to Wilwood calipers up front, no real difference. Followed the manual's troubleshooting procedure and it pointed to a bad brake booster.

I cannot tell you how much of a royal PITA it was to replace the booster, but I did it. It did make a difference in the pedal travel.

Brake pedal travel is one of those things that's tough to guage. I'm sure we could rig a device to actually measure the travel, but that's not really practical. Anyway, since replacing the booster, the brakes were usable but IMO not the same as they were before the incident at Sebring. Since then, I've installed a DRM master cylinder, bled the brakes a dozen times, switched pads, switched back to a brand new stock master, and the pedal is still more or less the same - quite usable but not ideal. I find that if I need to jam the brakes hard, the right side of my foot can actually hit the gas pedal. I've since learned to angle my foot better to avoid that. Part of that may be due to the fact that I have a wide foot.

Duke 1's comments about over-boosting may be close to the truth. One thing I notice, if the car isn't running or I disconnect vacuum to the booster, the brake pedal is VERY firm and travel is negligible. I wonder if there would be a way to limit the amount of vacuum going to the booster and if that would help?? Either way, there is NO way I'd want to go through replacing that booster again. :drunk:
 

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dmtnt said:
For the low, low price of...... :lol:

Really, the killer on those kind of braking systems is the consumables. How much are replacement rotors for those bad boys?
The Baer Pro+ Alcon kit with the 1+ CD/S/Z rotors is about $8k installed including SS lines and hi-temp fluids. Am running 14" Eradispeeds in the front and 13.5" in the rear - about $850 per pair for the Baer rotors. I have not any problem with brake pressure and peal modulation. I can stop from 160-20 mph repeatedly without fade....
 

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ScDFACHE said:
Am running 14" Eradispeeds in the front and 13.5" in the rear - about $850 per pair for the Baer rotors. I have not any problem with brake pressure and peal modulation. I can stop from 160-20 mph repeatedly without fade....
Ouch! I use $25 NAPA rotors and track the hell out of the car. With LG Wilwood front calipers, Wilwood H pads, SRF fluid, DRM ducts, and LG spindle ducts, I have run 45 minute+ sessions with NO fade whatsoever.

Not knocking your setup at all, its probably fantastic, but for us paupers, its unrealistic.
 
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