Rear Brake COMPLETELY Faded on Me

[DefyInertia]

Have you ever had this happen?

I was moving pretty good on a really tight 1 to 1.5 lane gravel strewn mountain road, using my rear brake A LOT for about 35 miles, and all of the sudden.....I had no rear brake AT ALL.

I could push the pedal all the way down with essentially no resistance. If felt like I had the bleeder open. This freaked me out of course, so I stopped and looked the rear braking system over to see what the problem was. Every thing looked fine but everything was extremely hot so I figured I overworked it until it failed.

Ambiant temp was around 80, brake pads have about 1/4 life left, and I've actually never changed the fluid in my rear brake system. I'm of course going flush the system with new fluid now.

So I simply boiled the fluid, right? I've never experienced such a sudden and extreme fade.

EDIT - here are the before and after pictures:

And the fresh fluid for contrast...

 

[RJ2112]

Have you ever had this happen?

I was moving pretty good on a really tight 1 to 1.5 lane gravel strewn mountain road, using my rear brake A LOT for about 35 miles, and all of the sudden.....I had no rear brake AT ALL.

I could push the pedal all the way down with essentially no resistance. If felt like I had the bleeder open. This freaked me out of course, so I stopped and looked the rear braking system over to see what the problem was. Every thing looked fine but everything was extremely hot so I figured I overworked it until it failed.

Ambiant temp was around 80, brake pads have about 1/4 life left, and I've actually never changed the fluid in my rear brake system. I'm of course going flush the system with new fluid now.

So I simply boiled the fluid, right? I've never experienced such a sudden and extreme fade.

I'd think you boiled the fluid..... luckily not to the extreme of forcing the pads into the rotor, just enough steam in the line overcome whatever pressure you could exert from the master cylinder. Think of it as a hot bubble in the line.

 

[Stumbles06]

Yeah, sounds like it got that hot that the fluid boiled in there. Unfortunately, there's not much you can do to stop it happening again (in sismilar circumstances), other than use the front brake a bit more, or slow down a bit

Scary stuff, glad you came through it ok.

:rockon:

 

[abraxas]

Thats freaky! Glad you survived it ! :thumbup:

But seriously, is that because the brake fluid is under the seat that is gets so hot?
Also that would be why it doesn't happen to front brakes?

 

[Humperdinkel]

I've boiled the fluid in my mates R1 before but never on the FZ or XJR.... The R1 was a couple of years ago during a very spirited run through a long steep set of downhill twisties , we found that new fluid & braided lines helped this problem :thumbup: Im guessing the the extra pressure you get from the braided lines means your not working the brakes as hard :don'tknow: & it was a higher rated brake fluid...

 

[Fred]

Yeah, sounds like it got that hot that the fluid boiled in there. Unfortunately, there's not much you can do to stop it happening again (in sismilar circumstances)

You can prevent it. As brake fluid gets old it absorbs water from the air. And the more water it absorbs, the lower its boiling point gets. So swapping to new brake fluid will fix the problem.

Fred

 

[DefyInertia]

You can prevent it. As brake fluid gets old it absorbs water from the air. And the more water it absorbs, the lower its boiling point gets. So swapping to new brake fluid will fix the problem.

Fred

This is my plan and I'm expecting it will buy me a significant amount of extra wiggle room. The fluid in there now probably has quite a bit of water in it.

 

[Motogiro]

Glad your good to go Nate! Had that happen in an old Oldsmobile coming down the mountains once.
This thread has some great info on reasons why we should keep that fluid fresh. I've never really thought of how moisture, which brake fluid likes to suck up, will readily expand during high temp conditions and of coarse create gas which is like air in the line, negating the hydraulic property of the brake fluid. Thanks to all providing info on this.

 

[sabre]

Never had it happen on a bike, but did have it happen on an old Dodge Dart I once had. Scary stuff.

 

[sabre]

Just a thought, that rear master cylinder is near the cat, which is of course a hot spot.
There I now have an excuse to spring for a decat pipe. SAFETY. :BLAA:
Thanks.

 

[ice]

Yes

A few years back I had an air cooled bike. I was riding with a group. We got caught in bumper to bumper traffic for a long time.
My clutch fluid boiled on me and I lost the use of my clutch for awhile. It was hot and I was totally frustrated.
After awhile my fluid finally cooled enough so I could use the clutch again and not speed shift.
I learned a valuable lesson that day.
KEEP CLEAN "HIGH TEMP." FLUIDS IN MY MACHINES AT ALL TIMES.

Brake fluid is used for the brakes and clutch.

You can purchase fluids with different boiling points. Read on the container.
I highly recommend high temp fluids for motorcycles.

I bought a late model used bike back in February of this year. The first thing I did was go through it from one end to the other.
Clean, high temp fluids were included in the service.
Good luck, ice

ps: If your brake was operable after everything cooled, most likely you boiled the fluid.
If on the other hand, the brake quit completely and you are missing some fluid,, then I would look for a leak.
















i

 

[DefyInertia]

Re: Yes

ps: If your brake was operable after everything cooled, most likely you boiled the fluid.

I let the brake system cool by continuing on down the road and not using my rear brake for a while. Operation returned to normal with no noticeable change from prior to the incident.

I've never had this happen to my front brakes as I keep fresh fluid in there and have SS lines and good pads.

 

[Norbert]

So the fluid is the 2004 brake fluid from the factory?
Post a picture of the old fluid when you replace it.
I bet it looks like chocolate milk. :BLAA:

 

[DefyInertia]

So the fluid is the 2004 brake fluid from the factory?
Post a picture of the old fluid when you replace it.
I bet it looks like chocolate milk. :BLAA:

As far as I know...I bought the bike in 2005 with 1,300 miles on the ODO. I'll post a picture.

I figured my rear brake was already waaay stronger than I needed it to be so why add an SS line or worry about it too much? Lesson learned.

 

[lonesoldier84]

I had a similar problem once.

Turned out I had "glazed" the brake pads and rotors. Scrubbing them with sandpaper was enough to fix the problem.

 

[DefyInertia]

I had a similar problem once.

Turned out I had "glazed" the brake pads and rotors. Scrubbing them with sandpaper was enough to fix the problem.

This is not what happened to me (I know you know that...just saying).

So how did that happen to you? Too much heat? Improper break in of the pads?

 

[Wavex]

Next time take the KTyum for off road stuff... problem fixed

 

[Norbert]

As far as I know...I bought the bike in 2005 with 1,300 miles on the ODO. I'll post a picture.

I figured my rear brake was already waaay stronger than I needed it to be so why add an SS line or worry about it too much? Lesson learned.

Could it be that you had your foot on the brake the entire time?
And it became too hot to work correctly when you tried to use it?

That's been known to happen. People ride around with their foot on the rear brake and not even notice it. I think this happens when they are very tense.

 

[DefyInertia]

Next time take the KTyum for off road stuff... problem fixed

I was ON road! :Flip: It's just a back back back back moutain road with dirty corners....it was the end of a 430 mile day and I was heading to my campsite.

PICTURE OF THE AREA I WAS IN

Could it be that you had your foot on the brake the entire time?
And it became too hot to work correctly when you tried to use it?

That's been known to happen. People ride around with their foot on the rear brake and not even notice it. I think this happens when they are very tense.

no this was not the case. I was very focused on my riding and was on and off the brake and all points in between. there were times when my throttle application and release of the real brake overlapped as well.

my rear brake was really getting worked...I was having fun using it more than normal and i also felt like I was making good use of it because I was doing quite a bit of dancing on gravel in the corner (using my front would not have been good).

 

[deeptekkie]

Yep, you boiled it and I've done it too, (except on the front brakes). Glad you're okay.