Avid juicy 7 stiff lever help

eeksll
Posts: 2290
Joined: Tue Oct 20, 2009 10:36 pm

Avid juicy 7 stiff lever help

Postby eeksll » Fri Nov 10, 2017 1:08 am

Hello, riding my MTB (avid juicy 7 hydraulic disc brake) today

the rear brake lever was very stiff;
it felt very on/off i.e no modulation;
the lever also felt like it was biting earlier in the lever stroke than 2 days ago (and now after the ride it feels like its back to normal);
also on the trail the brakes rubbing more than they are now, it spins quite freely now, but when messing with it on the trail, the wheel did not spin as much, but still free enough to spin a few rotations when the bike was upside down.

My initial thought is air is in the system (as thats the only thing I know can go wrong with hydraulic brakes :lol: ) but a bit of googling seems to suggest that air = sponginess which is the exact opposite of what I am experiencing.

I bled the brakes about a year ago, and this is the 3rd time I have ridden it.

thanks for looking, Any ideas?

jackthelad
Posts: 233
Joined: Sat Nov 15, 2008 12:24 pm
Location: Perth, Western Australia

Re: Avid juicy 7 stiff lever help

Postby jackthelad » Tue Nov 21, 2017 1:15 pm

how do you store the bike? if it is vertical with front wheel up or upside down, they just need a pump or 2 before use .
avids need a bleed every year, as Dot fluid is Hydrophobic.. absorb moisture ..
i take it you now how to align your brakes with the CPS washers, loosen brake calipers , hold lever tight, retighten brake calipers ...
may need a friend and beer/coffee if big bike .
you have lubed the actual pivot of the lever? inspected,as juicys are really ancient now... bearing probably gone...

have you lubed the pistons?
https://youtu.be/swwA2PwCIAw
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eeksll
Posts: 2290
Joined: Tue Oct 20, 2009 10:36 pm

Re: Avid juicy 7 stiff lever help

Postby eeksll » Tue Nov 21, 2017 1:59 pm

I lubed and bled the pistons about xmas time/start of this year. Only been 4 or 5 rides on the MTB since then.

Bike is stored upright.

I did some googling and stood the bike up on its back wheel for 24+ hours, hasn't seemed to fixed anything.
I would the lever adjust screw all the way in, pumped the lever a few times then all the way back out ...

I have the lever set a bit closer to the bars now.

On the last ride, I didn't notice the on/off braking so much, but modulation certainly seemed to be easier with the front. Is it possible there is just no grip with my nevagels making it feel on/off.

I did think the brake lever bite point changed over the course of the ride (1.5 hr ride) ie it was biting earlier in the lever movement than at the start of the ride.

Maybe Ill try another rebleed soon.

jackthelad
Posts: 233
Joined: Sat Nov 15, 2008 12:24 pm
Location: Perth, Western Australia

Re: Avid juicy 7 stiff lever help

Postby jackthelad » Tue Nov 21, 2017 2:27 pm

Rebleed with pads out and piston block installed, piston pushed all the way back
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SantaCruz Blur XC Carbon
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Calvin27
Posts: 1577
Joined: Sat Feb 09, 2013 5:45 pm

Re: Avid juicy 7 stiff lever help

Postby Calvin27 » Tue Nov 21, 2017 4:18 pm

Sorry to say but I gave up on avids a long time ago. Constant twice year bleeding at best and all sorts of issues with seizing.
Fast light bike
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Duck!
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Re: Avid juicy 7 stiff lever help

Postby Duck! » Tue Nov 21, 2017 11:01 pm

Brakes that use DOT fluid MUST be bled at least annually; the fluid absorbs moisture from the air, which increases the volume of the fluid in the system, and that extra fluid volume has to find some way to fit in the system plumbing, so it advances the pistons, reducing lever travel.

If you live in a wet or humid climate, you will need to bleed the brakes more frequently than someone who lives in a drier region.
I had a thought, but it got run over as it crossed my mind.

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