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Old 19th March 2007, 11:42   #1
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Default Brake fade on Vtec!!!

I'd taken the Vtec to a local garage on friday to get the center muffler removed (just wanted to see what it sounded like).

After having it removed, i took the car for a spin. The noise was irritaing as expected, so i took it easy till i got out of city limits. On the open highway, i maxed out 2nd and then 3rd gear (150+kmph). Thought i'd slow down a bit, pressed the brakes and to my horror there was absolutely "NO" braking. Somehow managed to halt the car using engine braking and pumped the brakes a few times. A few secs later the brakes felt normal so i did another high speed run to double check if the brakes would fade again and they surely did.

Not wanting to try my luck any furthur, i cruised back to the garage got the brake lines checked and the center muffler fixed. Took the car for another spin on the same road, did the same speeds but this time.....the brakes were perfectly fine.

My guess is that, due to the center muffler being removed, the hot exhaust gasses somehow managed to heat up the brake fluid to such an extent that it caused the brakes to fade completely.

So, the next time any of you guys think of modifying your exhaust layout, just make sure the the exhust heat doesn't get to any part of the car that might cause such failures.

Shan2nu

Last edited by Shan2nu : 19th March 2007 at 11:44.
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Old 19th March 2007, 11:51   #2
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Similar problems on an Esteem owned by a friend but it was not due to the exhaust but a failed brake booster - Esteem brake problem (Esteem Brake problem)
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Old 19th March 2007, 12:45   #3
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I got my center muffler removed a few months back and i have (Thank Dear God) no brake fade issues. I used to feel they are less effective b'cos the pedal travel was a little more than normal.

However got the pads and the related parts checked a week back and they were fine. Pad's needed a lil rubbing with sandpaper thats all. Got rid of that tiny niggling squeaky sound too.

Last edited by n_aditya : 19th March 2007 at 12:46.
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Old 19th March 2007, 18:02   #4
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shan2nu, are you pretty sure that the removal of the centre muffler and the subsequent heating up of brake fluid (where?) is the cause?

i too faced this situation once on my VTEC...

i was a little over 120kmph, on a free road of course, and the brakes did "fade out"!!!

i too used engine braking to get myself to safe speed limits and then could feel the brake returning back to normal once <80kmph.

by using your words "fade out" i mean literally fade out, but i had not done anything to any of the exhaust components.

the exact feeling was the brake pedal felt as good as normal, but the brakes were not slowing the car down.

but i did not face this again, though i do 80-120kmph between Mankhurd-Vashi and on Palm Beach road almost everyday.

and,... i had to slow down quickly in a short distance, say, from 140 kmph to almost 50 kmph on the Expressway on my weekend trip and the brakes worked wonderfully well, no fade outs, no screeching of tyres, nothing.

Last edited by gbpscars : 19th March 2007 at 18:18.
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Old 19th March 2007, 18:58   #5
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get ur brake serviced thoroughly including replacing the brake fluid and doing a proper bleed job
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Old 19th March 2007, 19:28   #6
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Quote:
I got my center muffler removed a few months back and i have (Thank Dear God) no brake fade issues. I used to feel they are less effective b'cos the pedal travel was a little more than normal.
Prob it doesn't happen on all cars. BTW, where was the exhaust opening? In my case the tip of the exhaust pipe was opening right in between the front wheels (under the engine).

My regular exhaust setup opens between the rear wheels, so no chance of hot gasses affecting anything.

Quote:
shan2nu, are you pretty sure that the removal of the centre muffler and the subsequent heating up of brake fluid (where?) is the cause?
It's not a question of whether you're running the center muffler or not, it's got more to do with where the exhaust pipe opens. . The Vtec comes with an auxilary muffler and a 2ndry muffler (twin pipe exhaust). I've been running without the 2ndry muffler for a long time now, and have faced no issues. It's only when you remove the auxilary muffler, the exhaust opens too close to the fuel and brake lines. This can cause a lot of damage.

Shan2nu

Last edited by Shan2nu : 19th March 2007 at 19:29.
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Old 19th March 2007, 20:58   #7
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Brake fade - when brakes get heated up and lose their bite due to expansion - commonly on drums

What you sufered was most probably an air lock due to excessive heat
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Old 19th March 2007, 22:53   #8
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Quote:
Originally Posted by ajmat View Post
Brake fade - when brakes get heated up and lose their bite due to expansion - commonly on drums

What you sufered was most probably an air lock due to excessive heat
Ive actually never heard of the "expansion" reasoning before.

I agree that the cause of brake fade is always heat, (and hence drums are more susceptible since they do not lose heat as fast as discs).

In your case Shan2nu, it could be -

The pedal felt firm and you pressed it as hard as you could but it didn't make a difference -
This would be pad fade, where the surface of the brakepad heats up so much that the resin actually holding the compacted materials of the pad together begin to melt and smear. In other words, the coefficient of friction of the pad changes very drastically past a certain temperature.

The pedal felt spongy -
This would be brake fluid fade, as Ajmat has mentioned. The fluid starts to boil, causing pockets of air in the system which can easily be compressed (and hence the spongy feel).
Usually fluid fade starts "bubbling" in the calipers, (because they are closest to the heat source) but in your case i wonder if the exhaust exit was closer to some part of your brakeline etc...

cya
R

Last edited by Rehaan : 19th March 2007 at 22:55.
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Old 19th March 2007, 23:04   #9
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I have experienced pad fade quite a few times during spirited drives in my lancer.

When you press the brakes real hard from high speeds once like 120 to 30-40 then again you accelerate and have to press again they dont work almost like they slip. but after a few mins of cooling they are fine again.
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Old 20th March 2007, 10:38   #10
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Quote:
The pedal felt spongy -
This would be brake fluid fade, as Ajmat has mentioned. The fluid starts to boil, causing pockets of air in the system which can easily be compressed (and hence the spongy feel).
Usually fluid fade starts "bubbling" in the calipers, (because they are closest to the heat source) but in your case i wonder if the exhaust exit was closer to some part of your brakeline etc...
Yup, thats exactly what happened. The fade wasn't due to the pads, but due to the the fluid boiling somewhere near the exhaust opening. The brake pedal was as spongy as the clutch pedal.

It's been 3 days since this happened and the brakes are doin great after the center muffler was re-fitted.

BTW, another thing i forgot to mention is that the plastic casing that covers the fuel lines melted when all this was happeneing. Luckily the fuel lines are made of metal so there was no damage there. Will be getting the plastic casing replaced soon.

Shan2nu
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Old 20th March 2007, 11:25   #11
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Hi Shan2nu,

You should consider fitting a exhaust wrap bandage. Should elimintae the problem completely. Also if you have not replaced your brake fluid so far recommend you bleed the entire system and put fresh DOT 4 fluid.

Viper
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Old 21st March 2007, 14:49   #12
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Viper I think thats a brilliant suggestion,however was wondering if its possible to wrap up the whole thing,right down to the end?
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