Does brake fluid go bad??

[OneSlowEclipse]

Since second creek my brakes haven't worked so well. Seems like I have to push on the pedal harder to stop. I know the brakes got pretty hot :D , can brake fluid break down under those conditions??

The pads look great still and the rotors look pretty good as well, any other suggestions? Maybe I should have the rotors turned?
Thanks

[DlandryTSI]

OOOOOOOOOOOOOOOOOOH yah brake fluid will definately go bad after as many laps as you did. More than likely you boiled it and its got a crap load of bubbles. I'd flush out the whole system front and rears to fix it.

--Dave

[OneSlowEclipse]

yeah, that's what I figured. Just wanted to confirm my thoughts, thanks Dave :)

[DlandryTSI]

Hehe You know you have bad brakes when you have to use the e-brake to stop the car (knows from experience).

--Dave

[OneSlowEclipse]

HA... its not quite that bad, but bad enough to make me nervous a couple times. Its pretty hard to make ME nervous (although I haven't ridden in yours or Brians car yet :mad: )

[DlandryTSI]

Hehe you might want to wait till my passenger seat has seat belts.

--Dave

[talonawdcars]

I used the Motul at 2nd Creek. After the second session my front discs were 550 degrees. Went back Tuesday afternoon for some 3 or 4 lap runs. My brakes are just fine.

Alan M.
www.DiscountSupermart.com

PS. 3 DSM's Stalking Their Lunch. LMAO :D

[OneSlowEclipse]

I was rather pleased with my brakes, they held up awesome for being basically stock GSX brakes. Even the time I went for like 10-12 laps (hehehe... I was having WAY too much fun) the car would still stop fine. I did get some higher grade brake fluid before I went, it had a boiling temp of 500 degrees.

I did get my brakes bled this evening, and the front brakes had quite a bit of "air" (or brake fluid vapor probably :) ) Now the brakes work better than ever.

[v413nc3]

Brake fluid can scortch, since it is hydraulic fluid. You'll notice when it is a different color. Normally dark brownish/yellow. Happens on the time on my bike. Also if you don't have SS brake lines those lines can swell under heavy braking pressure and sometimes can become misfigured causing iregular fluid flow, sometimes causing the brakes to feel really mushy.

[TDQuiksilver]

OneSlowEclipse.. may I ask what rims/tires you got on that sexy lookin' car!? Heh.. they look nice.

[OneSlowEclipse]

If I do any more racing at 2nd Creek I will for sure be getting SS brake lines, but for now there is no need. I did notice that the old brake fluid was much darker than the new, so you are probably right.

Ive spoken to you about the wheels already ;)

[Erron Spalsbury]

I cooked mine. A 150+ lap 3day weekend will do that. Here's the setup i ran. Porterfield R4-E pads, titanium brake shieds, motul-600(bled daily), Powerslot slotted rotors(cracked the crossdrilled last time), and the brake cooling ducts fed directly into the center veins of the rotor. By the end of the weekend the rotors have hairline cracks all over. I managed to do pull off the track after a cooling lap and had 653 degree rotor temp. By the 5th lap, they glow. I was threshold braking a few times at high speed, a little nerve racking coming up on that much traffic at times. They seemed to reach a high temp then not climb any more. I honestly didn't think the powerslot's would last all 3 days. I can't wait for the new brakes.:p

Erron S.

[v413nc3]

Nothing quite like wearing out a set of rotors. The only real good race setup doesn't work for squat on the street though.... carbon fiber, you gotta heat them up good to see any good use out of them, daily driving just isn't feasable.

[Erron Spalsbury]

Somewhat true. To reach the max braking point they have to be heated. Just like the R4-E, which is a carbon endurance pad. What this really means is that they work fine on cold days for ordinary driving, just not the max braking. With cold R4-E's i have every bit of braking power as i did with stock pads. When they heat up, they rock. Even with carbon rotors, they give the same effect. The next setup i'm going to is 15" directional veined rotors with 6 piston calipers and all carbon pads. I even have the option for carbon rotors at that point. But 3100 bucks each, mabe someday, especially because they are "consumables".

Erron S.

[v413nc3]

Consumeables is an understatement, they normally last me 1 race. Yeah, not going anywhere near my street car. LoL

[erik]

I still have mushy brakes but I replaced everything. When I had new front and back rotors and pads dropped in a few years back, I thought that the pedal would feel more responsive after the pads had seated. .. nope.
Lately. I replaced the front calipers with 2nd gen 2piston type, new OE larger rotors, new Axiss MM pads, new SS lines with speed bleeders on all four calipers. And then I connected a clear hose on one of the bleeders to monitor any bubbles, if there were, and checked to see if I can get the lightest shade of yellow/clear liquid flowing thru. I tried to purge the system with Valvoline synthetic and then drop in some Motul 600 for the track. That helped with the endurance at SC but it didn't get rid of the mushiness. A few weeks afterwards, I realized that the Motul is only for a temporary use. So I flushed out the fluid with the Valvoline synth. (by then it was darker again) ... No difference.
I do have good breaking power and it's sometimes not realized untill I get really on it, but in slower/lighter peddal pressure, it is very wimpy!
Could it be the master brake cylinder??? Those are very pricey. Anything else I could try?
... Oh and I have ABS. and 101,000mi.s on the car.

p.s. I know that the MM pads are a culprit for less "grabbiness" when cold but they heat up quickly. But that doesn't seem to matter there either.

[OneSlowEclipse]

My bakes act in a similar fashion Erik.. sometimes when I am lightly braking it seems like they aren't doing much. But there have been a couple times when I got on them sorta hard and locked up the front wheels too ;)

One thing I have also heard (on the 2gs anyway) is the master cylinder on the GSX is 1/16" bigger. This allows more fluid to reach the caliper and from what I have heard the dual piston calipers like that extra fluid. Whether there is any truth to that I don't know.

[DlandryTSI]

You both might want to bleed your brakes. More than likely all of us (especially me) boiled the brake fluid in the lines...

--Dave

[OneSlowEclipse]

The only time I have boiled the fluid was at Second Creek. I am not on the brakes nearly enough to boil it. Im a NT and therfore slow Dave, you gotta remember that.

Ive bled my brakes quite a few times now, no improvement in light braking. I think part of my problem is I got cheap brake pads with my calipers. Ive talked to a few others that have done the same conversion as me and they have had similar results so I don't think it is abnormal. One of these days I might pick up a GSX master cylinder and swap it out, just to see if it makes any sort of difference.

Oh yeah, and I still have rubber brakes lines so thats not helping things any.

[Van]

Originally posted by erik
Oh and I have ABS.


I think this is your culprit. Yank that pos abs system, install some big 13" rotors and you will stop with very little pedal pressure.

Fluid does go bad, it sucks up moisture like a dry sponge thrown into a puddle. When it's dark it's bad.

I also don't remember the MC being very pricey?

[OneSlowEclipse]

You are right, the master cylinder is pretty cheap. I had forgotten about that until this post was dug up, I might have to try it now.

[v413nc3]

the rubber brake lines if they've swollen in places can cause it to be mushy but not normally under light braking...

Van you suggest yanking the ABS system, I had considered doing the same but got a verbal tongue lashing from Mandy.

[DlandryTSI]

Heh screw ABS :D

--Dave

[erik]

ABS allows you to break faster even on dry pavement. But... I'll keep it for the mushiness then. Less of two evils. I don't think ABS is on race cars anyway but this is a daily driver, so I'll keep that for now.
As for an earlier reply about my fluid. ... notice that I mentioned that I drained it a few times. .. (Three times in a matter of a few weeks!) Each time very thoroughly.
I think Jason said that he bled his brakes several times, also, and no real improvement.
It's very important to do this and is important how it's done with what type of fluid and done more often with heavy use, than for the average user. I 'think' that I'm doing the best procedure on this exercise.
So it narrows down to two culprits ABS and the Master Cylinder. I'd replace my MC before taking out my ABS. .. Maybe I should sample with different pads. That could be it also. Lots of us use Axiss MM pads but Mike Stewart was saying lot of the Supra guys use a different brand pad that they have been very happy with. .. If my pads weren't so new I'd try them. I even have a set of R4-E's for the track....
Is anyone willing to volunteer for trying out these new pads from Mike? I think it would be worth your time, according to what Mike was saying about them. ??
I would be very interested in what they are like.