No Power at Rear Brake?

KiteCrasher

New Member
New to hydraulic brakes and have a question.

My Avid Juicy 7 rear brake has suddenly lost power. The lever feels solid when pulled in but there is no power at the rotor. I can pull the brake lever in and walk the bike forward and the wheel turns.

Pads are only a few months old.

Might I have contaminated my pads? or rotor? Any thoughts on the problem and how I may fix it are welcome.

Thanks
 
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ytc100

New Member
If the pads are contacting the rotors with good pressure chances are the pads are contaminated. Clean the rotor with alcohol and give the pads a light sanding. You may need to replace the pads entirely though.
 

KiteCrasher

New Member
Aluminum lever, no drag when pulled. Cleaned rotor and sanded the pads, still slips.

The front brake lever comes to a firm stop when I pull it in, the rear lever is firm but has a bit of a bounce and is a bit squishyyy?, Might a bleed be in order?


I see a trip to my lbs tomorrow.
 

ytc100

New Member
It's kind of strange to suddenly get air in the line but sometimes an air bubble can break free from it's hiding spot within the caliper or master cylinder. If the lever feels spongy it could also be a problem with the master cylinder itself.
 
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DANSPANK

Guest
Maybe the mineral oil has leaked and the system isn't full?
 

TJYeti

Knows about bikes
Maybe the mineral oil has leaked and the system isn't full?

Suddenly lost power when?- after a crash? Was there any fluid leakage around the caliper when you checked the pads? Look at the levers' plunger - any fluid there? I don't know the exact spec, but it's not like they hold a quart of fluid so it dos'nt take much of a loss to lose pressure. One finale thought - got any friends that like to play practical jokes and adjusted the pad contact dial out on you ?
 

mergs

Spokompton's Finest
JORBA.ORG
do you hang the bike up on a hook when not in use? i had a friend that swears every time he hung his bike up (i think it was by the back wheel) on a hook, it made his brakes run like they needed to be bled.

i only mention this wacky suggestion bc it sounds like you've covered all the other obv. bases. disclaimer: my buddy is not "all there", so ymmv ;)
 
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Phatbiker

Guest
do you hang the bike up on a hook when not in use? i had a friend that swears every time he hung his bike up (i think it was by the back wheel) on a hook, it made his brakes run like they needed to be bled.

i only mention this wacky suggestion bc it sounds like you've covered all the other obv. bases. disclaimer: my buddy is not "all there", so ymmv ;)

yep.. true story. i don't put my bike upside down for this reason.

phat
 
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DANSPANK

Guest
Yeah, I've read that turning your bike upside down to take the wheels off can make air travel down the lines towards the pads and mess up braking efficiency.
 
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Timekiller

Guest
Really... there shouldn't be air in the lines in the first place, then flipping the bike would not matter. :hmmm:
 

ytc100

New Member
Really... there shouldn't be air in the lines in the first place, then flipping the bike would not matter. :hmmm:

This could be the "air bubble hiding in the system" syndrome. Turn the bike upside down and the air bubble suddenly floats out of the nook it's been stuck in. I've had it happen to me right after a bleed. I always tap the calipers, levers, and all of the hose with a wrench when I bleed my brakes to help knock trapped air bubbles loose.
 

TJYeti

Knows about bikes
do you hang the bike up on a hook when not in use? i had a friend that swears every time he hung his bike up (i think it was by the back wheel) on a hook, it made his brakes run like they needed to be bled.

i only mention this wacky suggestion bc it sounds like you've covered all the other obv. bases. disclaimer: my buddy is not "all there", so ymmv ;)

My mother hung me on a hook once. Once.
 

anrothar

entirely thrilled
hydros w/ a resevoir anyway. magura rim brake style brakes can be stored any way you damn well please and continue to work superbly.
 
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