Imp

Changed my brake fluid and pads yesterday making sure no air was sucked into the lines or into the MC/ABS.

Took the car out and pedal has to almost go to the floor to stop.

Somehow, air must have been introduced throught he MC but I'm 99% positive there was fluid there all the time.

Any hints on how to get pedal feel back?

--kC

PUR NRG

How did you make sure no air was sucked into the lines? The reservior has partitions that can make you think there's still fluid when in fact the brake portion has run dry.

If the pedal feels spongy then you have air in the lines. All you can do is try a complete flush and hope that drives the air out.

I'd suggest posting exactly how you change the fluid to see if anyone can spot a bad technique.
________
Expert Insurance

dannobre

iTrader: (3)

Bleed MC then go back to wheels...then MC again......should take about 1/2 quart to re-bleed all the air out Must have got some air in through the reservoir....can be a bitch to get it out some times.

I have speed bleeders...and I refill the reservoir every wheel...otherwise it's really easy to go too low

Spin9k

Yea - it's ESSENTIAL to bleed the master Cyc BEFORE and AFTER the 4 wheel bleeding. My dealer didn't read the shop manual and sent me on my way with pedal to the floor brakes. Details matter! Bleeding the Master Cys was the fix.

mtnpass

+1

Imp

The shop manual doesn't even say to bleed the MC.

Went out and did it and yep.. there was air in it. Took it for a ride... better... but not good enough for a track day.

I've gone through 1.5 qts of brake fluid... there must have been air drawn in which means tomorrow it goes to a dealer to get flushed.

Damn.

--kC

expo1

Which one do you have?? Page 2 Brakes section

Imp

Reading is fundimental. It's amazing I got this far in life.

TeamRX8

iTrader: (25)

I didn't have to bleed my master cylinder, it shouldn't really be necessary as long as you don't allow air to enter it

did you try pumping it and pulling the pedal up by hand if necessary?

if you put new pads in it may take a couple of pumps to get the pistons out fully and pads seated on the rotor EDIT: never mind, you said you took it out and drove it, guess you f'd up

Imp

Ok... went to the track day anyways.

Bled the MC quite a few times and there was quite a few bubbles in there that might have gotten loosened in the transportation of the car and settled near the top.

Went through over a liter of brake fluid after doing and re-doing the MC until there was only cavitation. Still a mushy pedal. Went out for 1st session with mushy pedal, but it still stopped. Left plenty of room between cars. Came back in and raised the car so the MC was the highest point and let it sit there for a while.

Re-bled the MC.. a few more bubbles but not much. Went back to the wheels. Started with the rear/pass side. Opened it up... little bit of fluid then about 4 inches of air.. then a constant stream of fluid. There we go. The only thing I can think of is the 1st session worked the air to that caliper. The other three and the MC again and there was no more air.

Got back in the car... and the brakes were back to normal.

If that didn't work, I was going to borrow someone elses car (friend offered his STi for the track day... should have just said 'not working' ) and let the car sit there and gravity bleed.... but didn't have to.

Lesson learned: 99% positive != 100% positive.

--kC

PoLaK

iTrader: (1)

+2 same issue for me now i feel like i have the brakes of GOD

Huhwha

Heh - people make mistakes. I swapped my fluid for Super Blue ATE before my track day. Followed all the directions - MC, wheels in proper order, then MC again. Worked great.

Got to the track and parked. Prepping the car and noticed a small puddle and drip - what's this? Yup - brake fluid from the MC bleeder that I had neglected to tighten all the way! It was only finger tight! Tightened it properly and topped off the fluid and everything was fine. You can bet I checked it after every session though!

Huey52

iTrader: (2)

Yup, air in the line. Remember that air is compressible and hydraulic fluid is not.

PoLaK

iTrader: (1)

WAIT WAIT I had a lesson learned today! The MAX line really means the MAX line.
Don't get anywhere near the max line, don't even play with the MAX line in your dreams, because if you do (like i did), you'll find your abs system automatically braking your car and you not being able to move till you bleed off the MC of the extra fluid!

PS I had a fun day in the middle of the street not being able to move, with a 711 slurpie and straw as a make shift bleeder hose and container.

Red Devil

Hmmm...I just flushed my system three weeks ago and am right at the max mark. Ran a track session on it and the car was fine. Are you sure that's the problem?

PoLaK

iTrader: (1)

I'm pretty sure.... basically what happned was when i shifted my head bobbed forward alot more thne it should, sort like if i couldn't drive a stick feeling, then it just got progressivly worse up to the point where the car would not move and the ABS/Tracktion Control/ Check Engine Lights wents on.

Pretty shitty because you can't be towed with your car locking itself in place, I didn't even have to pump the brakes when i opened up the MC bleed screw fluid just came out and the brakes lifted.

RX8Maine

My brakes are all original and the fluid is right at the max line. No problems.

Red Devil

Never had that happen to me before. I'd like to hear one of the more mechanically inclined explain what was going on there. Sounds like your MC was partially engaged at all times for some reason?

PoLaK

iTrader: (1)

Well I thought more about what you said and it did indeed not make any sense for the abs light to turn on and stop the car just for having to much fluid; a CEL maybe but an all out stopping is a little extreme.

So I found the real culprit, CLICK

while bleeding the master cylinder I loosened the strut tower brace, when I was done I tightened it back up, and I tightened it really good. This gave me hardly any peddle travel and the "brakes of GOD", but it **** with the mc/abs system, so I loosened it a bit and I'm back to where I started, too much peddle travel......

I posted this thread and didn't get a response the MC on 04's and 05's are different I'm willing to bet it has something to do with how stiffly the MCs are mounted to the firewall or where the push rod is in the cabin, which would improve brake peddle feel what does someone more "mechanically inclined" think

dsmdriver

iTrader: (3)

There is no way the MC stopper on your STB goes from "brakes of god" to "too much travel."

If that were true, every 8 would have way too much from the factory, since there is no stopper at all.

Something else is going on here.

I'm guessing that pressing the MC too tight with the stopper causes the brake light switch to always be on, and this somehow messes with the ABS when it does it's check (a few seconds after you start rolling). Or worse, it binds up some valving in the MC, which causes your brakes to never back off after you press down on them, which would also make your pedal feel stiff, even though it wouldn't be acutating the brakes well at all.

PoLaK

iTrader: (1)

hummmm, well could bracing the master clyinder with a lot of pressure cause the push rod that goes into the car to be press futher in there by reducing travel?

or perhaps bracing the MC to hard places it at an angle that isn't pependicular to the power brake unit? Which accroding to the service manual can cause a variety of problems.

granted but my brakes (peddle travel) do not feel like another stock rx-8's no bracing sturt bar on his car until i do in fact brace it.

cjwaggs

You're a ******* idiot!!!!!! Learn something will ya!!

PoLaK

iTrader: (1)

excuse me?