Mountain Bike Reviews Forum banner
1 - 12 of 12 Posts

·
Registered
Joined
·
1,287 Posts
Discussion Starter · #1 ·
I've been running Juicy 5's since March of this year and recently I noticed the rear brake sometimes gets soft during a ride, but then later during the ride the brakes work fine. Sometimes they get so soft the lever is almost touching the grips.

I bled the brakes once already but it still happens every once in a while. Any thoughts and what is happening to temporarily make the brakes go soft?

I can't imagine that air gets into the system and then comes back out, so I don't know what is going on. I usually store the bike by hanging it on a hook from the rear-tire but I'm not sure how that could effect the brakes since I usually pump them a few times before I ride.

Would worn pads cause this to happen? The pads are pretty low but not down to the metal yet.
 

·
Meh.
Joined
·
17,508 Posts
Worn pads may cause this.

Chances are that you still have a small air bubble somewhere in the system though. Heat could cause the bubble to expand.
 

·
Registered
Joined
·
3,160 Posts
osmarandsara said:
I've been running Juicy 5's since March of this year and recently I noticed the rear brake sometimes gets soft during a ride, but then later during the ride the brakes work fine. Sometimes they get so soft the lever is almost touching the grips.

I bled the brakes once already but it still happens every once in a while. Any thoughts and what is happening to temporarily make the brakes go soft?

I can't imagine that air gets into the system and then comes back out, so I don't know what is going on. I usually store the bike by hanging it on a hook from the rear-tire but I'm not sure how that could effect the brakes since I usually pump them a few times before I ride.

Would worn pads cause this to happen? The pads are pretty low but not down to the metal yet.
More than likely there is still air in the system.
 

·
Registered
Joined
·
1,083 Posts
osmarandsara said:
I usually store the bike by hanging it on a hook from the rear-tire but I'm not sure how that could effect the brakes since I usually pump them a few times before I ride.
Should be fine if you're pointing fork down. If you turn bike upside down, then the bubble from the reservoir could enter the MC and cause sponginess. Depending on how far it gets, it could take a lot of pumps for it to come back into the reservoir.
 

·
Registered
Joined
·
74 Posts
I had exactly the same problem with my juicy 5 rear. Bleeding 5 times made no difference. The only thing that made a temporary difference was tying the lever to the bar overnight. I managed to cure the problem by fitting an elixir r brake last week ! I had read of someone with the same problem, doing a bleed and totally flushing out all the old fluid as well which worked. Tbh i'd given up by then though. Good luck !
 

·
Registered
Joined
·
311 Posts
i had the same problem with my rear jucy 5's last year. Over a 2 month period they would go from spongy to firm, and have to be pumped up while riding. I bled them a half dozen times during this process and must have finally gotten a good bleed, because they have been good for year now.

I did find that hanging the bike with the master cylinder the highest point with a rubber band holding he lever to the bar over night, made it easier to get air out when bleeding.

Overall Avid has a really stupid way of bleeding the juicy brakes, and they are very sensitive to any air in the system.
 

·
Dirt Deviant
Joined
·
3,694 Posts
Do you notice the brakes get soft after a steep up or down section? More so up than down?
If so, you still have air in the system.
Don't wait for your pads to get too close to the backing plate. Once it gets too thin, it can crumble and then you have metal to metal, in which case you will need new pads and rotors and may also do damage to the pistons.
 
G

·
If there is water or moisture in the lines; when the brake fluid gets hot, the water turns to vapor and results in spongy brakes.
I'd go along with the other guys who suggested air in the line as the primary cause.
 

·
Registered
Joined
·
1,287 Posts
Discussion Starter · #9 ·
thanks for all the suggestions......I'll swap out the pads and I'll bleed the brakes again when I get a chance.......(when I bled the brakes the 1st time I followed the instructions carefully and made sure I got the air out of the hose, lever, caliper, and the syringe....I can't imagine I left that much air in the system)

I wonder if there's something in the design that sometimes causes this problem for some people in the rear brake.....For example, the front brake has a shorter cable and the caliper sits in a vertical position and below the lever/master cylinder. However, the rear has a longer cable, and the caliper sits in a horizontal position.....so maybe it is more sensitive to air bubbles trapped in the system.
 

·
Registered
Joined
·
1,287 Posts
Discussion Starter · #10 ·
ronbo613 said:
If there is water or moisture in the lines; when the brake fluid gets hot, the water turns to vapor and results in spongy brakes.
I'd go along with the other guys who suggested air in the line as the primary cause.
great suggestion....but don't know how water/moisture could have gotten in......I live in SoCal and it hasn't rained here in about 1,000 years.....
 

·
Registered
Joined
·
1,287 Posts
Discussion Starter · #11 ·
savagemann said:
Do you notice the brakes get soft after a steep up or down section? More so up than down?
If so, you still have air in the system.
Don't wait for your pads to get too close to the backing plate. Once it gets too thin, it can crumble and then you have metal to metal, in which case you will need new pads and rotors and may also do damage to the pistons.
I can't remember if it happens when going up or down, but you just gave me a great idea. I'll try an experiment.....I'm gonna hang my bike from the front tire for a few hours and then I'll check the brakes......then I'll hang the bike from the rear tire and I'll check again for sponginess.......I guess if the brakes feel different each time that would solve the mystery of my spongy Juicy 5's.:D
 

·
Banned
Joined
·
356 Posts
I have the same problem. Mine have an aweful squeel to the rear brake also. They arein mint shape and the pads are new. I really don't like them at all. I am thinking of throwing on the Oro Puro's.
 
1 - 12 of 12 Posts
Top