Has this happened to you? Rear Brake ??

[J.Busa]

My buddy has an 04 Hayabusa. He doesn't ride it a whole lot but he did the other day and this is what he said happened...............


He was going along the hwy at over 100mph when a cager did something in front of him to make him get on the rear brake very hard. So hard in fact that he locked it up and the rear tire was skidding.Not stopping near as fast as he thought he needed to he let off the rear pedal and got on it again.This time he said it went all the way down w/ no pressure at all....Lost the rear brake totally.

Well, luckily he got stopped in time and pulled off the hwy to check his shorts and the bike...No rear brake at all.After letting the bike sit for about 30-45min he got the rear brake to pump up and got rear brakes again, but he said there is no fluid leaking anywhere and he now has rear brakes again w/out having done anything but wait that few min....BTW- fluid is clean in the res.

What do you guys think happened? Is there something he needs to check? I've never heard of this, but I've never had to do anything like that before either..

 

[memorex]

In a panic during the second attempt to stop his foot wasn't on the rear foot pedal correctly. Or After the first attempt the fluid became to hot to have any real presure.

 

[Charlesbusa]

I don't know....


But your friend is REALLY lucky he didn't highside when he let go of the rear brake.

Over 90% of your braking power is in the front. worry less about the rear brake and learn to use the power of the front brake.

 

[Glyn]

04, stock pads, lines, fluid, and it sits a lot?

Could be a little moisture in the fluid. As it gets hot, it lets the fluid compress ( I forget the exact reason, but it has something to do with the amount of water content, it will absorb moisture, and boil off when hot, creating an air in the lines feeling)

Flush and change the fluid every 2-3 years. Especially on one that does not get a lot of use.


Or he missed the pedal in all the excitement

 

[Revvv]

I don't know....


But your friend is REALLY lucky he didn't highside when he let go of the rear brake.

Over 90% of your braking power is in the front.  worry less about the rear brake and learn to use the power of the front brake.

Exactly

 

[Cerberus]

I don't know about the brakes, but I had my clutch do that on my Zuki Intruder. It had sat up for a while and I figured I should take it out. It fired up, and off I went. After a block or two the clutch just quit working. I worked when I started but then just quit. After sitting along side the road a while, it worked again. After I got home I bled the clutch and all was good. No problems since. I know mine was a different part but the symptoms sound the same.

 

[SAMBUSA]

Sounds like he boiled the fluid and lost pressure.

+1 on the being lucky. If you lock up the rear, leave it locked.

 

[MO-BUSA]

I don't know....


But your friend is REALLY lucky he didn't highside when he let go of the rear brake.

Over 90% of your braking power is in the front.  worry less about the rear brake and learn to use the power of the front brake.

amen brother

 

[BIKE DUDE]

When I use to go to the ski areas with my mountain bike I sometimes got the hydraulic disc brakes so hot doing downhill runs that they would over heat the dot 3 fluid and I would loose my brake lever until they cooled. I switched to dot 4 with a higher boiling point and that made the difference. But your friend said he locked the brake up which doesn't cause enough friction between the pads and the rotor to get the brake fluid that hot unless he was riding the brake before hand without knowing it(no friction,no heat,no boiling,no vapor,no loss of brakes). So....I would say thats not the problem(heat) and if it really happened the way he said, he could have an intermittantly bad master an the rear(internally leaking past seals),inter. bad caliper(? never seen that,it would leak),inter. collapsed brake hose(? once bad stays bad) which are all very uncommon. These parts usually fail and stay failed so to be safe, should he replace them all? No, I have seen the occasional master work sometimes and not others when they first start to go bad so if I had to guess, I'd try that. Usually if your brakes fail and then come back a few seconds later(maybe do to cooling off) it is heat related but in this case I don't think locking up the brakes once or twice real quick would do this so that points to a master that is starting to fail. Is that your final answer? Yes, final answer.

 

[runeight]

04, stock pads, lines, fluid, and it sits a lot?

Could be a little moisture in the fluid. As it gets hot, it lets the fluid compress ( I forget the exact reason, but it has something to do with the amount of water content, it will absorb moisture, and boil off when hot, creating an air in the lines feeling)

Flush and change the fluid every 2-3 years. Especially on one that does not get a lot of use.


Or he missed the pedal in all the excitement  

r8

 

[runeight]

Sounds like he boiled the fluid and lost pressure.  

+1 on the being lucky.  If you lock up the rear, leave it locked.

Pretty high boiling point Sam. Not likely IMO.

r8

 

[runeight]

http://www.shotimes.com/SHO3brakefluid.html

r8

 

[SAMBUSA]

http://www.shotimes.com/SHO3brakefluid.html

r8

 

[J.Busa]

Thanks for all the input guys. I really think it does have something to do with the bike sitting for so long. ('04 w/ 4000miles). Either the condensation in the fluid scenario or the master cylinder starting to fail from sitting so long.Either way, I suggested he bleed the whole system out and replace the fluid, wich he said he was gonna do anyway.

I wasn't there so I don't know EXACTLY what happened but as I said he doesn't ride much so maybe his skillz were a bit rusty and he didn't do what he thought he did.One things for sure, he was LUCKY he didn't highside or worse.

I told him to quit acting like a damm dirt biker on the Busa and get off the rear brake. Those things are about useless on a sportbike.

Thanks everyone!

 

[JusPlaynBob]

Thanks for all the input guys. I really think it does have something to do with the bike sitting for so long.

Regardless,
it's best to just take his keys.
Your doing him a favor.

 

[pbghost]

stock brake line? might be expanding... mine used to do the same, would flush the lines and it would improve a little for a while. then I replaced with galfer s/s lines. what a difference! they're not much, and well worth it.

 

[him]

Hell i couldnt get my 01 back break to lock the tire if my life depending on it.

 

[raydog]

Everybody above sure covered most of possibilities....one more though, it's called a lazy hydraulic piston.....it might not be returning after the 1st application....could be long term results of water (I don't mean sponginess) wall corrosion. Especially since bike's been sitting. Raydog

 

[BIKE DUDE]

Everybody above sure covered most of possibilities....one more though, it's called a lazy hydraulic piston.....it might not be returning after the 1st application....could be long term results of water (I don't mean sponginess) wall corrosion. Especially since bike's been sitting.     Raydog

My dad had that. Viagra!! LOL

 

[delbert]

Hell i couldnt get my 01 back break to lock the tire if my life depending on it.

my 99 was the same, rear brake absolutly cr#p, turned out the pedal was part siezed on the shaft. took off , cleaned and greased , refitted, skiddy skiddy