HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
Ga426owner

03 rear brake issue - as in no brakes

6 posts in this topic

Symptoms - rear brake pedal has been loseing pressure and stated to go through entire stroke - last few months as bike has sat for a while

last night I checked it and it bottoms out completely - no braking at all to rear wheel - tried pumping the pedal...did not increase pressue at all. Pads are fine - fluid is full

I assume the caliper seals are bad as the system is air tight and no leaks. If this is this is the case - do I need to replace anything else ie...piston assembly etc...

Anyone else had this issue? What else could it be?

Share this post


Link to post
Share on other sites

See if one of these scenarios fits:

>The pedal travel to brake contact feels normal, but there is less than normal resistance to pedal pressure. No air can be found in the system, and there are no external fluid leaks.

Likely cause: a softened brake line.

>The pedal travel to brake contact feels normal, but holding pressure on the lever causes the pedal to drop farther the longer you hold it, eventually coming to a stop. There are no external fluid leaks.

Likely cause: leaking master cylinder piston.

Share this post


Link to post
Share on other sites

yep that is what I thought to but no brake fliud leaks at all.....

I am stumped.....

it is more the first scenario - it feels like air is in system but no air is. Brake petal pumping will not get any pressure to build up...period. sounds like metal to metal clanking.....maybe I should buy a new brakeline and a master cylinder rebuild kit?

What would a bad caliper seal symptom be? air in system right? no fluid leak either right?

Share this post


Link to post
Share on other sites

Caliper seals are not normally a source of air getting in, because the caliper piston moves very little. It's probably the master.

The way the rear brake is routed, there's a great big place for a bubble to live right where the line attaches to the M/C. Be sure the master is full, crack the fitting loose, and push the caliper piston back a little. Then, push the pedal down and hold it, tighten the fitting, and release the pedal.

Remember that you'll have to pump the caliper back out.

Share this post


Link to post
Share on other sites

I've never had any luck manually bleeding brakes on a MX bike. A vacuum bleeder makes bleeding brakes easy.

Share this post


Link to post
Share on other sites
Caliper seals are not normally a source of air getting in, because the caliper piston moves very little. It's probably the master.

The way the rear brake is routed, there's a great big place for a bubble to live right where the line attaches to the M/C. Be sure the master is full, crack the fitting loose, and push the caliper piston back a little. Then, push the pedal down and hold it, tighten the fitting, and release the pedal.

Remember that you'll have to pump the caliper back out.

crack the fitting loose at the brakeline & M/C, by pushing the piston, this should force air if trapped there out......hmm thanks Grey I will try this....

bleeding the brakes is the easy part for me....:thumbsup:

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0