So I did a lapping day yesterday and at the end of the day my brakes seemed a little soft. I figured it was no big deal since I had been pounding them for like 3 sessions that day.

I let the cool off when I get home and about 3 hours after I left the track the brakes STILL feel kinda spongy.

Now I get home from work this evening and take my car out to run an errand and the brakes aren't quite as soft but they are still pretty spongy.

I am using Cobalt GT Sports in the front and rear and ATE super blue fluid (which was installed in April but has been bleed recently.....say mid-June). Normally this combination is extremely grippy even when the pads are cold and a very hard pedal...i.e. relatively little pedal pressure to stop the car.

I havent tried to bleed the brakes yet, nor did I do so before the track day (and I know I should have, but the pedal was really hard before anyway...I figured it was unnecessary).

Would bleeding the brakes, or flushing them for that matter, help any?


BTW Since the brakes started getting soft on me towards the end of my session, I'm kinda thinking about upgrading again. But I'm not sure whether I should do the pads or the fluid or both. And Im not quite ready for a race pad as the car sees about 100 miles of street time a week.

Thanks in advance

 

give them a good bleed/flush.
I flushed my brakes before summit and didnt have to bleed them all weekend.

 

Mushy pedal=boiled brake fluid. Once the fluid boils, there is no turning back. So YES bleeding the brakes should solve your problem. I would also remove your dust shields (heat sinks) if you have not already done so. If that dosent help then I would upgrade the pads, then add ducting, and lastly I would swap out the fluid. The Ate should not be the weak link. If all that dosent work that get a Stoptech kit with some big azz rotorz.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by smokin rubber &raquo;</TD></TR><TR><TD CLASS="quote">give them a good bleed/flush.
</TD></TR></TABLE>

He dosent need to flush the system if he swapped the fluid in April. Unless he left the cap off the reservoir, let the bleed screws open for a few days, and let some rain fall in.

 

Check the pads themselves. Uneven wear (as in, the pads are wearing at an angle) could cause a soft pedal.

They might also be glazed...switching to a known-good set of pads will tell you this.

 

Is there a honda owner in here who doesn't need to bleed their brakes after a HPDE weekend? Maybe I'm alone, but I thought this was commonplace with our cars.

 

brakes soft during a session but all better next session: switch pads

brakes still soft the next day: upgrade to DOT4, if already upgraded, bleed fluid

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JeffS &raquo;</TD></TR><TR><TD CLASS="quote">Is there a honda owner in here who doesn't need to bleed their brakes after a HPDE weekend? Maybe I'm alone, but I thought this was commonplace with our cars. </TD></TR></TABLE>

We rarely bleed brake fluid unless its during a caliper change or we boiled the brake fluid (the latter has occurred once this year, don't recall an occurrence last year but I don't have the best memory). The car is garaged however and we do probably swap calipers once every five race weekends (or 10 or so races).

 

I'm with phatty.

I don't bleed them very often. Couple of short pumps (prior to the weekend) to get the old fluid out of the caliper and I'm ready to go.


John- Who ownz braking zones.

 

thanks guys. im probrably gonna bleed them regardless.

ill check the pads tomorrow. alot of people seem to think that the pads may be glazed and I was kind of wondering about this myself. im not sure if ill recognize a glazed pad from sight though.

now if the ROTORS are glazed (which I can identify) does that automatically mean that the pads are glazed also?

if thats the case, i guess ill be needing a new set of rotors and pads.

another thing that im wondering about is Jacob's suggestions about rotor cooling. in what specific situations could removing the shields on my rotors warp them.

Remember I very seldom drive the car. Its mostly there for the weekends and for trips to and from the track.

Thanks again for all the quick responses.

EDIT: about boiling the fluid, I doubt this happened as I had enough braking power to slow the car sufficiently at the end of the straight all day. I was under the impression that if you boil the fluid there will be NO pedal pressure at all....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NB &raquo;</TD></TR><TR><TD CLASS="quote">

EDIT: about boiling the fluid, I doubt this happened as I had enough braking power to slow the car sufficiently at the end of the straight all day. I was under the impression that if you boil the fluid there will be NO pedal pressure at all....</TD></TR></TABLE>

not true......when you boil the fluid there gets to be little pockets of air in the lines. now the next time you press the brakes the air is compressed initially (without actually applying the brakes), and once the air is compressed, then the fluid can "flow" and initiate braking. hence the "soft" brake pedal.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tnord &raquo;</TD></TR><TR><TD CLASS="quote">

not true......when you boil the fluid there gets to be little pockets of air in the lines. now the next time you press the brakes the air is compressed initially (without actually applying the brakes), and once the air is compressed, then the fluid can "flow" and initiate braking. hence the "soft" brake pedal.</TD></TR></TABLE>

and the air doesnt recompress once the fluid has cooled? is that why it would stay spongy?

 

Once you've got air, you've got air. It's always going to be there, ready to be compressed next time you press the brake pedal. Only way to get rid of it is to bleed the brakes.

Try tapping the calipers gently with a rubber mallet while you bleed them. I've found this helps dislodge air bubbles that get trapped. If you boiled the fluid and created bubbles in there this might help.
-Adam

 

once the air is in there.....it's there. that is, until you bleed em. that's the problem, once you boil the fluid, the brakes will remain spongy until you take the necessary steps to remove the air.

i'm not exactly sure what your statement means, but i hope i answered accordingly.

 

what i was understanding was that the "air" we were talking about was the boiled brake fluid in gas form (since there really is no way for actual AIR to get in the lines).

I would have imagined that once the fluid cooled back down, it would recompress and turn back into fluid.

My assumption was wrong (even though it doesnt make much sense to me) and YES you did answer my question. Thanks.

 

I just went through this after a solo I school in my Prelude. The brake fluid is toast. If you have a 5th gen, the brakes can get very hot. Make sure to take your cooldown lap if possible.. I need to add ducting or something.

After bleeding the brakes out really well, all was good.

 

When this happened in my 240SX, it turned out to be a leak at one of the crush washers sealing the line to the caliper.

It's probably boiled fluid, but, check for leaks!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AKADriver &raquo;</TD></TR><TR><TD CLASS="quote">When this happened in my 240SX, it turned out to be a leak at one of the crush washers sealing the line to the caliper.

It's probably boiled fluid, but, check for leaks!</TD></TR></TABLE>

i had a similar problem with the crush washers leaking. it was weird. under hard use the brakes would get a little air in them and get mushy. use em gently for a while and the leak would "self bleed" (not all the air, but it would bleed it till there was less then before) chased it for 3 weeks before i noticed a brake fluid soaked front wheel on my car and went hunting to find the leak.

when the brake fluid boils, it isn't actually the fluid boiling but the small amount of water in the fluid. (you'll never be able to have 100% dry fluid) once the water boils, it leaves behind the air bubbles that are the bane of any hydraulic system. bleed them and your probably should go away. if it doesn't, check for sticky slide pins, un-even pad wear, leaks, or a bad brake hose.

nate

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JeffS &raquo;</TD></TR><TR><TD CLASS="quote">Is there a honda owner in here who doesn't need to bleed their brakes after a HPDE weekend? Maybe I'm alone, but I thought this was commonplace with our cars. </TD></TR></TABLE>

I usually don't need to but about every third weekend.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NB &raquo;</TD></TR><TR><TD CLASS="quote">what i was understanding was that the "air" we were talking about was the boiled brake fluid in gas form (since there really is no way for actual AIR to get in the lines).

I would have imagined that once the fluid cooled back down, it would recompress and turn back into fluid.

My assumption was wrong (even though it doesnt make much sense to me) and YES you did answer my question. Thanks.</TD></TR></TABLE>

It's really not the brake fluid that boils. It's water that's trapped in the brake fluid. Brake fluid is hygroscopic (it absorbs water even from the humid air it is contact with) So over time there gets to be a certain amount of water in the brake system. When it gets hot enough to boil the water you get water vapor bubbles in the fluid. They do not all go back into solution when they cool. Then you have a compressable gas in your brake lines and mushy pedal.

 

If you're doing HPDEs, bleeding brakes often is very cheap insurance against bad things happening. It forces you to look at and think about your brake system.

And who knows, maybe you'll find a problem you wouldn't have noticed otherwise.

Ask yourself this; do you believe there is a successful race team that does not bleed the brakes between each race AND inspect the entire braking system?

Is there a best practice to be gleaned here from successful race teams for our HPDEs?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JohnW &raquo;</TD></TR><TR><TD CLASS="quote">I'm with phatty.

I don't bleed them very often. Couple of short pumps (prior to the weekend) to get the old fluid out of the caliper and I'm ready to go.


John- Who ownz braking zones.

</TD></TR></TABLE>

How is this not bleeding??

Also, I bleed before AND after every HPDE. I have even bleed a few times during lunch break.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NB &raquo;</TD></TR><TR><TD CLASS="quote">ill check the pads tomorrow. alot of people seem to think that the pads may be glazed and I was kind of wondering about this myself. im not sure if ill recognize a glazed pad from sight though.

now if the ROTORS are glazed (which I can identify) does that automatically mean that the pads are glazed also?

if thats the case, i guess ill be needing a new set of rotors and pads.

another thing that im wondering about is Jacob's suggestions about rotor cooling. in what specific situations could removing the shields on my rotors warp them.

Remember I very seldom drive the car. Its mostly there for the weekends and for trips to and from the track.

</TD></TR></TABLE>

That is a good question. I am not 100%, but I think that it is possible for the rotors to be glazed and not the pads. But again, I am not sure here.

Some normal street driving should cure both the glazing on the rotors AND pads, however. But since you dont drive the car except for the weekends, you can take some garnet paper (I found some at Home Depot,, in the same isle as the normal sand paper.) According to Stoptech, garnet paper is made of different material than normal sandpaper and is better suited for the job. You can sand the pads lightly, and pretty much go to town on the rotors with even, circular motions.

No down side for removing the shields. Unless you drive through the forest and over boulders, there is no down side to removing them. That is the number 1 place to start with brake cooling.

 

Here is the paragraph about garnet paper from THE stoptech article( http://www.stoptech.com/whitep...h.htm )

The obvious question now is "is there a "cure" for discs with uneven friction material deposits?" The answer is a conditional yes. If the vibration has just started, the chances are that the temperature has never reached the point where cementite begins to form. In this case, simply fitting a set of good "semi-metallic" pads and using them hard (after bedding) may well remove the deposits and restore the system to normal operation but with upgraded pads. If only a small amount of material has been transferred i.e. if the vibration is just starting, vigorous scrubbing with garnet paper may remove the deposit. As many deposits are not visible, scrub the entire friction surfaces thoroughly. Do not use regular sand paper or emery cloth as the aluminum oxide abrasive material will permeate the cast iron surface and make the condition worse. Do not bead blast or sand blast the discs for the same reason.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by siisgood00 &raquo;</TD></TR><TR><TD CLASS="quote">

How is this not bleeding??

Also, I bleed before AND after every HPDE. I have even bleed a few times during lunch break.</TD></TR></TABLE>

A couple of 1/2 pumps to clear the calipers is far from what others call 'bleeding'.

John- who witnesses all the time " up-down, up down, up-down... add fluid... up-down, up-down, up-down........................ and continue for another 20 mins.

I think some are trying to find that "rock-hard" feel, when all they should do is get a good set of pads and proper fluid.

IMO.