Brake Fade

I was riding yesterday down a steep long single track and was riding the back brake ALOT. After a while I noticed it starting to squeak and not much longer after that there was NO BACK BRAKE. The lever just went all the way down with no resistance.

I played around with it for a while and thought that maybe I was out of fluid. I checked the level and it had plenty. It was probably more than five minutes by the time I got done checking it.

I pushed on the lever again and presto I got brakes back. Kinda scary.

Has anybody else had this problem? Was I just riding them too hard too long and the fluid boiled and just needed time to cool? Is there something else I should be checking….the caliper the master cylinder?

They seem to be working fine now and I’m gonna drain the fluid, put in fresh and bleed them before the next ride but I just want to see if this is a common problem or if there is something else I should be checking.

Any advice would be welcome. :thumbsup:

Yeah,the same exact thing happened to me coming down Miller jeep trail at gorman.Luckily i was almost at the bottom of the mountian when it happened.It was like no pedal pressure at all.I took some water from the stream and cooled off the rear caliper(xr650l) and the brake pressure came back.

My brake pads were about 2/3's worn so i figured there was less material to absorb the heat.I replaced the pads(factory honda) and brake fluid (dot4) and haven't had a problem since.(but i haven't been down Miller again yet so...)

Its the disc that absorbs the heat, weather the brake pads are new or 2/3 used wont make any difference in how much heat is absorbed by the system. Putting water on a really hot brake is a really bad idea. It will warp you disc, making your breaks suck. If the caliper was hot enough, it could even warp the cylender making your breaks suck even more. If they get way hot and fade, just give it some time let them cool off by themselves..... :thumbsup:

I switched to a high temp brake fluid, stainless lines and got rid of the stock pads once they wore out. Since then both the front and rear have been a lot stronger in all conditions, esp. in the mud and snow. :thumbsup:

What kind/brand of aftermarket pads did you go for??

If the disc absorbs the heat then why does the brake fluid in the caliper boil?More pad material will insulate the caliper better than less pad material.All parts of the brake system close to the rotor/pad friction area absorb generated heat.

So when ever you do a stream crossing you stop and let your bike cool off?I never warped a rotor(on a dirt bike)going thru water!

Yeah...what type of fluid and pads are people using?

I'm just glad to hear it happens and that I just need to let them cool down when it does.

Of course the caliper gets hot, anything connected to the brake system is going to get hot. But they total heat absorbed by the system is dictated by the Disk, not the brake pad. Having a new pad as opposed to a mostly used pad is NOTHING when looking at how much heat the system will absorb. Fading is caused by the disk heating to the ponint that the brakes no longer work. Having your brake fluid biol is anohter issue, and that would be solved by using DOT 4 or other high temp brake fluid, but again it is not a function of the pads being worn.

Having a different type of pad will make also a huge difference how the brakes grab the disk, but again its not a matter of if your pads are new or 2/3 used.

Shock cooling really hot brake discs is a REALLY BAD idea, just because you have gotten away with it in the past doest mean its a good idea.

I went with EBC motocross pads, not sure what they are made of, I did try a carbon composite pad the local wrench recommended but in the wet they were crap. These new EBC's are red and allow me to do a stoppy on the front, couldn't do this b4. Brad :thumbsup:

He said the brake pedal lost all pressure(which is what happened to me).Not that he still had pedal pressure but the brake didn't work(fade)!I am a ASE certified Master technician and have owned 30+ dirt bikes and your trying to school me on brake systems? HA !

I went with EBC motocross pads,

Thanks!

You are right, I should have read his post better, he did not have fade. You may be a mechanic, but you obviously have a lot to learn if you say shock cooling a very hot rotor and caliper is a good idea, so yes some schooling for you would be in order.

You made a statement that does not apply to what happened here... "So when ever you do a stream crossing you stop and let your bike cool off?I never warped a rotor(on a dirt bike)going thru water! " Most water crossings are NOT made when the brake system is hot to the point of not working anymore. At normal temperatures this would not be a problem. This guy put water on a VERY hot brake to cool it off, not just water on a brake that was warm from normal trail use. You being a mechanic should know better than to cool a VERY hot brake disc and caliper with water, can you say WARP ?

I never said it was a "good" idea.When it happened to me i tried waiting to let it cool off.After 15 min. i got bored and was 3 hours away from my truck and in the middle of nowhere.I carefully poured water on the caliper(not the disc)and instantly pedal pressure came back.

I know you can warp(car) rotors that way.I'm just saying i've made many stream crossings on hot bikes and never had a noticeable problem.Off road racers do it all the time and i've never read about it being a problem(and you can bet they have Hot rotors)

I have nothing to learn from you.

P.S.- "most stream crossing are not done with overheated rotors" i don't know about you ,but i ride fast and abuse my rear brake to the point of fading being felt,so i know the rotors are HOT.But i guess your faster and you have warped your rear rotor and caliper.

Nah, im not that fast :lol: Biggest heat problem I get is not enough airflow over the motor when im in bad terrain where im going though water and stuff. :thumbsup: They only way I ever heat up my disks that much is going down 12,000 foot mountains !! Wasnt trying to jump all over you, just wanted to make sure that guy didnt start pouring water all over his hot disks :awww: A new pad insulating the caliper makes a hell of a lot of sense, would help keep the fluid from boiling.. Also DOT 4 brake fluid would help that dude, as opposed to DOT 3 which vaporizes as a lower boiling point.

STFU.gif

I use the old insulation pads with the new pads and havent had any problems since. I ride alot in the Highlands and it is very steep. I find this is the best way to stop this problem and is cheap

I totally agree with what the Japaneese guy said !!!!!

totally agree with what the Japaneese guy said !!!!!

Are you sure? I think he said to cool your rotors with ice water, and that JetPilots blow alot of hot air.

IMO, to avoid brake fluid boiling, change your fluid at least twice a year and use Motul RBF 600 brake fluid.

Boiling points of Motul brake fluids. All 3 are compatable.

................Dry / Wet

Dot 4.........473 / 316 F

Dot 5.1......509 / 365 F

RBF 600.....593 / 420 F

The specs on Neo's Super DOT 610 are very attractive with a dry boiling point of 610°F and a wet boiling point of 421°F. http://www.neosyntheticoil.com/bkfluid.htm

Castrol SRF is another brake fluid to check out if money isn't a problem because this stuff is super expensive ($60+/liter). It has a dry boiling point of 590°F, but a 'wet' boiling point of 518°F!!!

You were close, the Japaneese guy didnt say that Jet Pilots blow a lot of hot air, he said that Jet Pilots are [@#$%&*!] Hot :thumbsup: Not really haha. The Japaneese guy really said "Make the best out of where you live and it will become your kingdom.. Mark Jones..." :awww:

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