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Old 30th August 2010, 18:40   #1
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Question *Yikes* Brake fade / No Brakes - Cause and Solutions

On the road this would be scary even deadly
But thankfully I was't.

Many of you guys would agree OHC has a very eager brake pedal.
It bites and mostly locks up even at a hint of pressure.

I found the swift brakes adequate except when you are doing triple digit speeds.
After driving around in the OHC, Swift brakes scare the crap out of me.

Coming to the problem at hand.

History

Quote:
Track day (July 11- 2010)

Back straight.
I was braking from around 140Km/Hr. I brake early, blame it on being a "bike" guy till around 2006. In this case I'm thankful that I did. Instead of slowing down my OHC Vtec just goes on...

I end up carrying too much speed I downshift to 3 and into C4 and the back steps out.
Did't spin out but I did manage to get "off" the track. Engine stalled and I was a bit shaken.

Got the show back on track and dive into the pits.

Manek is grinning as he left me in the dust. I tell him I ran out of brake and track.
He thinks I'm BS'g. Tells him to have a go and see, 15-20 minutes later he drives and I'm in the passenger seat. He taps the brake and tells me I'm mad. At that point brake is fine.

Exits the pits into C2, C3 brakes for C4 he feels its a bit low.
Exits C7 and into C8 he brakes and car just goes on. He is a bit shaken.

Take it to the pits and lets it cool. Brakes never recovered after this during the track day and I did't do much "hot" laps after that. I entertained myself by carrying more speed through the corners by lifting off and braking early.. very very early.

This happened half way through the session.
The brakes did't overheat I can tell since we did a hot lap in his vtec and the alloys are radiating more or less same heat as mine.

Fluid levels are fine and fluid is not hot in the reservoir.

I've already resurfaced the rotors and the pads are new done at 64500Kms and after that done around 500Kms.

Did not change the fluid as I was told its not required.
I was told that "old" brake fluid can cause this as it will accumulate moisture and brings down the boiling point.
Another theory was the fluid used is DOT3 and it should be DOT4. (I guess DOT4 is being used now)

Right now brakes feels just perfect except for the horrible squealing noise.
I got them checked and was told pads are fine.

On the road there is no way to replicate the issue as we will not be able to brake like that.
After this I got the brakes checked and has not felt the fade.

Present Day

The same fade happened yesterday Track day on 29 Aug 2010.

I was literally standing on the brakes after 2 hot laps and there is absolutely NO stopping power. Simply put however hard I stomp the pedal I'm "unable to lock up the brakes" = No stopping power.

Please read this too
Brake Performance Tips

I was suspecting Green fade earlier as I had done only 500Kms with the new pads on the July track day. Now I've done more than 2000kms (66xxx Kms) and the pads seems to have bedded in properly. Seems the contact patch is normal and the rotors are fine and feels good.

Fluid fade is unlikely as the "fluid" was never hot, just warm as mentioned earlier.

Booster / Master cylinder seems to be fine. (Its doing its stuff)

Please note this happens only on the track and on normal roads the brakes are fine. Went today morning and tested it with left foot on the brake and right on the accelerator to heat it up. A hint of fade was there, but nothing drastic.

I'm suspecting pad fade.

Also folks who have driven their OHC's / OHC Vtec's on track. Please let me know what pads you are running. (Make - Eg : KBX, Bosh and is it OE approved ?)

Needs suggestions/views/resolution/theories.
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Old 30th August 2010, 21:01   #2
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I was running stock pads from Honda. I think they use Nissin. No brake fade at all, i was able to brake harder and further down the straight as i gained confidence with each lap.

I faced sudden brake fade once, when i had tested my car without the exhaust. The prob was due to the hot exhaust gasses heating up the brake lines (under the car) to such an extent that it melted the plastic cover around it and prob caused the fluid to boil.

I hit the brakes at 150kmph and it literally felt like i was pressing the clutch pedal. No braking force at all. Luckily i tried it on an empty stretch.

Slowed the car down with engine braking and the braking power started coming back again as the fluid cooled down.

So get you exhaust system check first and then move to the other parts. The braking on a stock OHC is brilliant and should not be showing such fade.

http://www.team-bhp.com/forum/techni...fade-vtec.html (Brake fade on Vtec!!!)

Shan2nu

Last edited by Shan2nu : 30th August 2010 at 21:04.
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Old 30th August 2010, 21:05   #3
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Quote:
I've already resurfaced the rotors and the pads are new done at 64500Kms and after that done around 500Kms.
What pads are you using?

How are you able to tell that fluid is not getting hot?
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Old 30th August 2010, 21:18   #4
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Thanks for the reply guys.

Quote:
Originally Posted by Shan2nu View Post
I was running stock pads from Honda. I think they use Nissin.
Quote:
Originally Posted by Mpower View Post
What pads are you using?
I'm using OE pads, Honda it seems has 4 "approved" suppliers for OE pads.
Exact make I'm yet to find out, its not shown in the bill.

Quote:
hot exhaust gasses heating up the brake lines (under the car) to such an extent that it melted the plastic cover around it and prob caused the fluid to boil.

So get you exhaust system check first and then move to the other parts. The braking on a stock OHC is brilliant and should not be showing such fade.
Did't see anything wrong. Will check again armed with this info.

Quote:
Originally Posted by Mpower View Post
How are you able to tell that fluid is not getting hot?
The fluid (in the reservoir) is not hot to the touch. Its not even warm.
Logic being if the fluid is getting boiled at the other end it should feel a bit hot. No ?

I'm not sure I can be 100% certain if it is/if its not boiling at the caliper end.
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Old 30th August 2010, 22:05   #5
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Was using OE. Switching to Black Diamond next month.
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Old 30th August 2010, 23:16   #6
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Quote:
I was told that "old" brake fluid can cause this as it will accumulate moisture and brings down the boiling point.
The brake fluid does not boil: the moisture in it boils. A very small amount of moisture creates a very much larger amount of water vapour.

Why is this a problem? You cannot compress a liquid, but you can compress a gas. If your brake fluid has bubbles in it (of air or of vaporised moisture), then the mechanical effort is being wasted in compressing the bubbles, and does not even reaching your brake pads.

Get your brake fluid changed, and make sure they bleed the brakes properly.


(Physicists and engineers: I don't know if I have the theory exactly right, but in practical terms, I think it is ok)

Last edited by Thad E Ginathom : 30th August 2010 at 23:17.
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Old 31st August 2010, 00:57   #7
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Quote:
Originally Posted by yzfrj
The fluid (in the reservoir) is not hot to the touch. Its not even warm.
Logic being if the fluid is getting boiled at the other end it should feel a bit hot. No ?
No.
Dude, I have one thing to say to you: DOT 4!
Replace the current DOT3 fluid(right?) in your system with DOT4, and most importantly do it properly. There shouldn't be air in the system whatsoever.

Pad fade can happen. But, this would be the first step.
This should solve it 99%.

Last edited by nitrous : 31st August 2010 at 01:00.
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Old 31st August 2010, 10:43   #8
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Quote:
Originally Posted by Thad E Ginathom View Post
The brake fluid does not boil: the moisture in it boils. A very small amount of moisture creates a very much larger amount of water vapour.
Yes sir, right you are brake fuild is hydroscopic.

Quote:
Originally Posted by nitrous View Post
Replace the current DOT3 fluid(right?) in your system with DOT4, and most importantly do it properly. There shouldn't be air in the system whatsoever.

Pad fade can happen. But, this would be the first step.
This should solve it 99%.
Its is DOT4 now nitrous. Yes agreed fuid change seems to be another logical step. I'd like to get the problem pin pointed.

I can change the fluid, complete brake overhaul, even replace the pads.
I'm pretty sure this will solve it.

But... the actual cause will remain a mystry. Since the only way to replicate it will be to test it out on the track next time. There is no way to get this replicated on public roads.

Quote:
Originally Posted by pranavt View Post
Was using OE. Switching to Black Diamond next month.
I guess its not OE. How much vitamine M for this ?
I was told about Hawk pads, freaking expensive for a consumable item.

I'd rather save up to get Tarox, I guess they can be done in an OHC.
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Old 31st August 2010, 11:07   #9
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Quote:
Originally Posted by yzfrj View Post
I guess its not OE. How much vitamine M for this ?
I was told about Hawk pads, freaking expensive for a consumable item.

I'd rather save up to get Tarox, I guess they can be done in an OHC.
Around 40-45 GBP retail, then the usual tax, duties and shipping stuff. So probably somewhere in the region of 4-4.5K INR.
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Old 31st August 2010, 11:17   #10
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Quote:
Its is DOT4 now nitrous.
Honda fills Dot 3 in my car and it works well. So i doubt its the brake fluid grade that is causing the prob. More to do with the condition of the fluid.

Shan2nu
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Old 31st August 2010, 14:36   #11
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I'm still betting on moisture or air in the fluid!
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Old 31st August 2010, 14:50   #12
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Yes I also think it is moisture in break fluid and thad explained.

BTW it is advised that DOT3 and DOT4 should not be mixed does anyone know why ?
But I remember for Hero Honda CBZ bike disk breaks a mixture of DOT3 and DOT4 is recommended and that is the strangest thing I have seen ( read it long back in manual of my 00-01 model bike)
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Old 31st August 2010, 17:56   #13
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Not clear. Do you have Dot4 or not?
Quote:
Instead of slowing down my OHC Vtec just goes on...
Does the pedal sink to the floor does it still bite at the same point when cold.
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Old 31st August 2010, 18:14   #14
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Quote:
Originally Posted by Mpower View Post
Not clear. Do you have Dot4 or not?
Does the pedal sink to the floor does it still bite at the same point when cold.
Yes it does have DOT4

Pedal travel is more (say another 25-30%) than normal when the fade sets in.
Its not really going to the floor.

It feels like the brake of a matador van (if you have driven one you'll know).

Let me explain : Its a strange feeling, the brake bites (the initial sharpness is lost however). The car slows a bit and from that point on it simply does't slow down. Naturally to compensate I stomp on the pedal harder.

It feels like no amount of force (on the pedal) is enough to stop the car.
If I pump the pedal its a bit better and this is actually required to shed the speed with the fade.

I literally stood on the pedal and still the car goes on.
It feels like the front brakes are completely gone or if someone has put grease between the discs and pads (you know the same feeling when the drum brakes gets flooded with water.)
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Old 31st August 2010, 18:33   #15
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Quote:
Let me explain : Its a strange feeling, the brake bites (the initial sharpness is lost however). The car slows a bit and from that point on it simply does't slow down. Naturally to compensate I stomp on the pedal harder.

It feels like no amount of force (on the pedal) is enough to stop the car.
If I pump the pedal its a bit better and this is actually required to shed the speed with the fade.
Hmm, the symptoms are more pad fade related. Fluid related symptoms should make the pedal feel very spongy and give you lots of pedal travel. Which is what i experienced.

Find out what pads your car is running.

Another thing to note would be your braking points on the track. Where exactly were you braking on corners where you experienced fade and what was the max speed your car was hitting just before braking?

Shan2nu

Last edited by Shan2nu : 31st August 2010 at 18:39.
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