Hydrolic brakes failure question...

[JoeTruth]

[SIZE=3]I have a set of Hayes Hydro's that I've had on my bike for about 5 years now. A few months back, I experienced total hydrolic brake failure under extreme use coming down a 3/4 mile section of a very steep descent. Once my hydro's cooled (1-2 minutes), I pumped the levers and re-gained full power and finished ride. I realize this can happen when the oil breaks down and gets very hot so I took my bike in and had F&R brakes re-bled with new oil and replaced F&R pads along with a new rotor for the rear (slightly bent).
Well, I happen to do that same ride last week and the same exact thing happened again. This is very dangerous when you're coming down a consistently steep section where it's virtually impossible to stop and the only thing you can do is lay the bike down. If I descend normal type of single tracks (El Prieto, Winter Creek, etc.), I never have such problems. Only on steep fire break type of descents where you're consistently on your brakes for a sustained period. What gives?

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[mechmann]

1 get bigger rotors
2 learn to use the brakes sparingly
3 get better brakes (as well as larger rotors)

those are your options... no matter what you should do #2. #1 will help, #3 will help more but will cost more.

[Chewyeti]

What you are experiencing is called 'Brake Fade' as we call it on race cars. The Pads + rotor slow you by friction - correct? friction makes heat.... Heat is absorbed by the rotor.... but once the rotor is maxed out on heat retention (and not cooling fast enough) the heat must go elsewhere. (into the pads which boils the fluid... which inturn makes a spongy feel or no feel)

solutions -
use better fluid. In race cars, we ran silicone or motul fluid. higher boiling points are what you are looking for.
2) Bigger rotor. Bigger rotor has more mass by which it can store heat, and dissipate it faster due to more surface area with the cooling air.....

in cars... you could also use brake ducting etc, hard to apply on a mountain bike..... with drilled rotors already

Just my 2 cents.....

[Sprockethead]

Stop using your brakes and learn to drift.

[Chewyeti]

2 words - drag chute :P

[JoeTruth]

Originally Posted by Chewyeti

use better fluid. In race cars, we ran silicone or motul fluid. higher boiling points are what you are looking for.
2) Bigger rotor. Bigger rotor has more mass by which it can store heat, and dissipate it faster due to more surface area with the cooling air.....
Just my 2 cents.....

[SIZE=3] That makes total sense and is sound advise. What weight oil are you referring to? Considering I'm 200 lbs., 8" rotors (vs. 6") F&R wouldn't also hurt.
I'm experiencing total and complete failure. During it's peak, when levers are depressed, you get nothing but air and depressing them serves no purpose.

Mechmann, thank you for your input. As shocking as this may sound, I'm convinced I know how to use my brakes and use them as sparingly. On this descent, if you're not on them the whole way down (excluding an occasional stop), you will end-up airborne and on the other side of the canyon or ODB before you can say "brake, God Damn it!". Gravity is not on your side, in this case. Not recommended for the faint of heart.[/SIZE]

[mechmann]

yeah... i have ridden some pretty hairy stuff. have you ridden The Plunge? talk about a brake burner...

just like in race cars, the best way to make sure you don't fade is to not use the brakes until you have to. don't brake on straights. only brake before a turn, and only just enough to slow down enough for the turn. all it takes is a few seconds of no brake contact for the components to cool down.

[JoeTruth]

Originally Posted by mechmann

yeah... i have ridden some pretty hairy stuff. have you ridden The Plunge? talk about a brake burner...

just like in race cars, the best way to make sure you don't fade is to not use the brakes until you have to. don't brake on straights. only brake before a turn, and only just enough to slow down enough for the turn. all it takes is a few seconds of no brake contact for the components to cool down.

[SIZE=3] No, I have not ridden the Plunge but know of it.
To give you a better perspective, there are no straights or turns. Technically speaking, not a very difficult descent, just a little steep and a little loose.

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[allison]

Originally Posted by JoeTruth

[SIZE=3] No, I have not ridden the Plunge but know of it. [/SIZE]
[SIZE=3]To give you a better perspective, there are no straights or turns. Technically speaking, not a very difficult descent, just a little steep and a little loose.[/SIZE]

No straights, and no turns? That's no possible on this plane of existence

What fire road is it you are descending??

I ride my brakes a *lot* and have never had them (not even my 140/160 brake setup) fail completely!!

Get Avid Juicy 7's if you're having that much of an issue!!

[JoeTruth]

Originally Posted by allison

What fire road is it you are descending??

[SIZE=3]Not a fire "road", a fire "break" and an old overgrown one at that. A slight difference in grade.
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[allison]

Originally Posted by JoeTruth

[SIZE=3]Not a fire "road", a fire "break" and an old overgrown one at that. A slight difference in grade.[/SIZE]

I guess my only suggestion then is to ride actual trails/fire roads? You may not have an issue with brakes then ?

If you haven't already, check out http://www.geoladders.com for some routes local to you.

[JoeTruth]

Originally Posted by allison

I guess my only suggestion then is to ride actual trails/fire roads? You may not have an issue with brakes then ?

[SIZE=3] LOL...that's very funny. Thank you![/SIZE]

[allison]

Originally Posted by JoeTruth

[SIZE=3] LOL...that's very funny. Thank you![/SIZE]

I'm actually being serious!!

The place you ride may be nearby, but if it's making stuff fail that really shouldn't be, I dunno... it's up to you where you ride, though

[spookydave]

what elevation is this happing at?

[JoeTruth]

Originally Posted by allison

I'm actually being serious!!

The place you ride may be nearby, but if it's making stuff fail that really shouldn't be, I dunno... it's up to you where you ride, though

[SIZE=3]I was actually being a bit sarcastic. I have lots of options and places to ride. That's not the problem. Maybe I like coming down steep stuff. Just like everyone else and everything else, variety is the spice of life.

It's all good and by no means does this mean I'm an almost pro-rider nor I know what the hell I'm doing.
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Originally Posted by spookydave

what elevation is this happing at?

[SIZE=3]Not very high altitude. I would guesstimate the start of descent to be around 2700-3000 feet tops.[/SIZE]

[spookydave]

If I'm reading this right you do have 6" rotors right? At least put an 8 on the front. I have 6 on my xc bike and 8 on the others. Big difference mang. It might just squeek you by.

Oh, sounds like a fun trail btw.

[ghixon]

Originally Posted by Sprockethead

Stop using your brakes and learn to drift.

Or some good health insurance....

[Chewyeti]

8's will help with heat retention and will SLOW the brake boil....(more heat dissipation ability also) but if you are on em too long, you can still boil the fluid...

tis my understanding you can use ANY dot 3 or 4 brake fluid with most hydrAUlic brake setups.... look at the bottles for one with the highest boiling temp. In the race cars we liked ATE super blue fluid or MOTUL fluid.

BTW - are they spongy feel before they fail? BLEED, BLEED and BLEED more!

[JoeTruth]

Originally Posted by Chewyeti

BTW - are they spongy feel before they fail? BLEED, BLEED and BLEED more!

[SIZE=3]Nope, not spongy at all. Funny thing is, they were engaging on my descend at one point, my front tire begun to wash out so I sort of came to a stop with an easy side landing. The minute I got up, I went to go depress the levers and re-mount but there was nothing there, front or back. I walked a little until they were cooled down, meanwhile pumping the levers every 20 seconds or so. Eventually, they started re-engaging and I finished my ride. I think I will re-bleed and use a Dot 3 or 4 oil which has been tested and certified for higher temps.

Thanks for the info!
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[Chewyeti]

fresh fluid! bleed bleed bleed. you can never bleed em enough

also, fluid breaks down, how old is the fluid?

humor me - change the fluid, bleed, and report back