my friends 09 classic lost rear brakes going down a curvy mountain road over the weekend.he said he had no peddle at all then after a few miles it came back.no abs and he said he didnt get started down good before they gave out so he doesnt think they over heated.he hasnt put any air in the rear shocks so i dont think that had anything to do with it.brake fluid level was fine and 2 weeks later still has brakes.any ideas what happened?

 

I have no answer to the problem, but I would bring it in to the dealer and have it checked out before I would ride it again. At least change the fluid. Maybe he was riding the brakes a little, unknowingly, and heated up the fluid?

 

really sounds like overheated

 

Overheated the brake fluid. Probably was in too high a gear too.

 

How was the color of the fluid? I had a similar experience fluid level was okay but color was cloudy so I assumed it got contaminated with water (maybe did not have the cover tight enough and water got in it either during a washing or from rain). Replaced the fluid and made sure the cover was tight and had not had any re-occurance.

 

If you heated up the brakes, you could have "boiled" the fluid.
If it's Dot3 and old, it may have absorbed water and that's what happend.
When you let it cool it all went back to normal.
It's gotta come out or bad things will happen
You or your dealer SHOULD flush the system, (open the top off the master cylinder-DON'T GET ANY ON ANY PAINTED SURFACES- IT'LL EAT IT, TRUST ME!!!!!!)
Open the bleeder at the caliper and let it gravity drain. (I use a small dia clear hose from Lowes, let it drain into a cup or bottle. When it comes out clear, (it'll be from **** yellow to bad **** brown) you've flushed the entire system. Not hard.
Keep the resisvior full of fluid at all times.If you let it run dry, you'll get air in the line and then you have to get that out, sometimes a pain, so keep it full!
I'd use dot 4 or 5 fliud.
Might as well do the front whilist your there.
You should do this once a year!
Joe
Don't let brake fluid touch anything- it hates the world!

 

Sounds like they were overheated. Bleed brakes and all should be fine.

 

I've done the flushing using the same type of fluid but never heard of doing what you describe.
Can you switch from dot 3 to dot 4 or 5 without replacing seals?
If so, can you do it without completely draining then refilling (can you push the dot 3 out while filling with dot 4 or 5)?

 

This same thing happend to me on Pikes Peak. The dealer, Pikes Peak H-D, said it happens all the time there on. When bikes go into high altitudes for some reason the fluid boils and air bubbles get in the line and cause the issue.

 

Dot 3-is Mostly car fluid
Dot 4 or 5 have a HIGHER boiling point. All my bikes have dot 5. (Spend the few $$ and get the better. You be more comfortable on your ultra loaded up with everything including the kitchen sink, your spouse barreling down a hill!)
Basically most fluids are the same stuff but with something?? to make the boiling point higher.
Now, you can use SILICONE, that doesn't ever absorb water, (ALL brake fluid absorbs water in the air, never keep an open bottle @, when it's yellow, it got water in it)
Silcione is great, once replaced, forget about it.
You gotta clean the entire system out, no old brake fluid though. I swapped regular fluid for silicone and just flushed it good.
The seals won't matter if you use 3-4-5 or Silcone.
If it won't gravity bleed or you can't get a good brake pedal,
What I do is
I have a "Brake syringe" I bought at a auto parts store, (but I've used a turkey baster with a clear hose)
Fill with fluid and WITH ALL THE AIR OUT, ( get you syringe lower than your calpier and hose higher a bump to push the fluid out, (like a nurse giving a shot), gently push fluid from your caliper TO your master cylinder, (this is called reverse bleeding).
Get you master empty before hand.
This pushes the air from the calp to the master.
Or you can PULL the fluid out by placing the hose on the bleeder pulling the plundger out,kinda "sucking" the fluid out.
Sometimes you gotta reverse bleed to get the air out as it get's stuck in the someplace.
You can do the old pump the **** outta the lever crack the bleeder and SQUIRT fluid all over, but that's hard on your master cylinder. This is a much better method.
Get you master higher than your calp and you'll gravity bleed.
Once you do it, you see it's not hard. Just DON"T GET ANY AIR in your lines. Air can't compress and you'll go "*&%%^$$@@#!!!!" when you try to stop.
When you done flushing the system, gently pump your brake lever and it should all be good!
Joe