Squishy brake pedal

[friday]

During jzilla's November trackday my brake pedal started going lower and lower after each session. The brakes still work but the pedal feel is quite awful. Monday my dad and I bleed the brakes at each corner and he was getting air from both the front calipers, but not the rear. The brake pedal felt better while bleeding, but soon it returned to not good. I thought I had worn the pads down at the track day, but there is still quite a bit of pad depth left. I do have some new pads to swap though.

I will say I did not bleed the brakes in the suggested order. So far my plan is to go back and bleed the brakes again and make sure that all the old fluid is out of the system most of it should be gone at this point). I will double check for leaks but I did not see any while working on the car.

Is there anything else you guys suggest? I know this has got to be a fluid issue.

[CMP]

Pump the brakes with the car off. If the pedal doesn't firm up almost right away, it's probably a master cylinder issue.

[friday]

***WARNING: Possible innuendo content ahead.***

Okay tested that. On the first press the pedal is pretty firm, and only gets stiffer from there. I keep my foot on the pedal and turn the car on. Pedal goes to floor. Turn the car off and in 3 pumps the pedal is back to full firm. Why does it lose pressure with the car on? From what I have heard a failing brake booster will never make the pedal softer.

[Dr.Drew]

Well if you keep pumping till its stiff but goes flaccid the moment the action gets started your master cylinder has some performance anxiety. What about the lines? Are you getting enough suction? I find without proper suction it can be difficult to remain stiff enough to properly make the pads grip and get some traction.

[friday]

and there it is.

[Dr.Drew]

I promise that I tried really hard not to.

Daniel is driving right now but his should be here shortly.

[friday]

I need real help before Daniel arrives!

[CMP]

It goes to the floor when the car is on because the booster is assisting and the fluid is allowed to flow freely. Stomping the pedal with the car off is a quick test to see if your master cylinder holds pressure, which it seems to be doing. Your booster should also be fine.

And contrary to what the doctor above may prescribe, your car doesn't need little blue pills.

[RotorNutFD3S]

I'm assuming no fluid leaks or loss? Stock lines or aftermarket?

Daniel is in the thread...

[Beastinthebushes]

Ok, whew! traffic was a *****.

Upon reading your issues, I've noticed a few things. You are rushing this!

Before you start tapping anything, you need to warm the car up first, so go ahead and turn her on. Now, while sitting in your car, go ahead and grab the stick and wiggle it a bit, what the hell does that have to do with the brakes you ask? Trust me, it just does. Since the car is on, we are gonna want to set the mood just right, so crank up that radio and play a little Barry Manilow or Kenny G, you know, to help get the juices flowing. Once you know the juices are flowing, stop everything! Turn her off and wait! This is called a tease. Your car will want more but you need to hold your ground and resist! Eventually your car wont be able to handle it and she will want you to tap those brakes rapidly.

NOW, PAY ATTENTION! Don't just go all gung ho with the tapping like your foot is a hammer and the pedal is a nail. You gotta start off slow, the first few pumps are the worst, but it will become a natural feeling, just listen to your body. Once you really start to feel the vibe, you may notice some bleeding occuring, thats ok, its perfectly normal. Once the bleeding begins, dont look back and give your all with every pump! It may sound like your car is hurting, but it isnt, these are all normal sounds. Now, from the position you are in and the length of your body, it may be difficult to tell if this method is working. You can try to reach around and feel the under carriage, but sometimes this just wont work. This is where its helpful to have a friend, make sure he is wearing the right attire and LATEX GLOVES! Have him squeeze up under the car and examine everything, tell him to watch out though cause we don't want him to get poked in the eye or god forbid he get some fluid in his hair. Throughout all of this, you may notice the some things getting lose, but with proper lubrication and the right fluids and tools, all will feel stiff again. Just when you are finished, Go ahead and fill her up properly, and you should feel a little spark in that relationship again.

Blue pills wont help, but a cock ring will.

[friday]

I'm assuming no fluid leaks or loss? Stock lines or aftermarket?

None that I saw, but I will double check when I go to work on them again. For now lets assume there are none. The lines are OEM. Brakes worked great before track day.

[salvadorr90]

Ok, whew! traffic was a *****.

Upon reading your issues, I've noticed a few things. You are rushing this!

Before you start tapping anything, you need to warm the car up first, so go ahead and turn her on. Now, while sitting in your car, go ahead and grab the stick and wiggle it a bit, what the hell does that have to do with the brakes you ask? Trust me, it just does. Since the car is on, we are gonna want to set the mood just right, so crank up that radio and play a little Barry Manilow or Kenny G, you know, to help get the juices flowing. Once you know the juices are flowing, stop everything! Turn her off and watiit! This is called a tease. Your car will want more but you need to hold your ground and resist! Eventually your car wont be able to handle it and she will want you to tap those brakes rapidly.

NOW, PAY ATTENTION! Don't just go all gung ho with the tapping like your foot is a hammer and the pedal is a nail. You gotta start off slow, the first few pumps are the worst, but it will become a natural feeling, just listen to your body. Once you really start to feel the vibe, you may notice some bleeding occuring, thats ok, its perfectly normal. Once the bleeding begins, dont look back and give your all with every pump! It may sound like your car is hurting, but it isnt, these are all normal sounds. Now, from the position you are in and the length of your body, it may be difficult to tell if this method is working. You can try to reach around and feel the under carriage, but sometimes this just wont work. This is where its helpful to have a friend, make sure he is wearing the right attire and LATEX GLOVES! Have him squeeze up under the car and examine everything, tell him to watch out though cause we don't want him to get poked in the eye or god forbid he get some fluid in his hair. Throughout all of this, you may notice the some things getting lose, but with proper lubrication and the right fluids and tools, all will feel stiff again. Just when you are finished, Go ahead and fill her up properly, and you should feel a little spark in that relationship again.

Blue pills wont help, but a cock ring will.

Very good write up lol

That's just too funny

[miatastuff]

As anything race car prep related, I turn to Carroll Smith:

http://www.centricparts.com/files/Centric%20White%20Paper%20D1-Brake%20Fluid%201A.pdf

and

http://books.google.com/books?id=S0sNFyNwPBYC&lpg=PA191&ots=rBJ6E5yUuo&dq=engineer%20to%20win%20bleeding%20brakes&pg=PA191#v=onepage&q&f=false

[Spark!Plug]

funny with a bent intake valve daniel described my cars current starting procedure o.0

when i was reading and what struck me is the fact you have a squishy pedal after a track day with OEM lines. that sounds just about normal. some SS lines and that problem goes away on the track. i assume you've only bled the brakes with the car off perhaps? if so, try after the pedal goes to the floor. the rubber lines do "balloon" when you start to boil the fluid on a track... .02

[friday]

Thanks for the links David. I think I actually have the Engineer to Win book somewhere.

[atlnb]

might just be time to flush your lines

[jester911]

You have more than likely cooked your brake fluid. This will cause these symptoms.
Flush and refill with new fluid. If you are going to do track days you need a higher temp fluid.

I used Super Blue/Gold when I did track/racing weekends. The fluid is actually blue or gold and when change fluid you swap colors so when flushing it out you see the color change and know when the old is completely flushed.

Used for many track weekends in my old 911 and Miata.

[GLudlow]

I had similar symptoms, it ended up being a badly leaking ABS pump. First pedal push good, second bad, third drops to the floor. Quick pushes and travel was restored.

Is your fluid level dropping? I didn't see your response on checking for leaks, but that's my first guess. I didn't see any fluid on the floor for mine, it was leaking into the engine, probably dropping only when I drove.

[friday]

UPDATE!

So I flushed and bled the brakes a few times, changed my pads, adjusted the rear brake, and swapped in a new master cylinder. It never really got a lot better, but the brakes worked well, it's just there was a lot of pedal travel that I was unhappy with.

So I figure that since the pedal is adjustable I should be able to get rid of the slack. Took the seat out and crawled under the dash. Adjusted the pedal for a little while and now it feels fantastic. It went from sloppy long travel to getting down to business as soon as you put your foot down. I love it. If you have ever adjusted a loose throttle cable at the throttle body you know the feeling.

[Jack-MX5ATLanta.com]

Glad a simple solution prevailed (eventually)!

[RotorNutFD3S]

Glad to hear that's what it was! :)