2009 Front brake issue?

[easybake323]

So I have bleed (several times now) rebuilt the master cylinder, The brake lever will get super firm and work fine but then ride it any distance it looses all pressure I can pump them up and they will work but ride any distance and they go limp. I have done the zip tie trick over night no leaks anywhere. Still has stock brake lines scratching my head not sure wtf is going on.

 

[Berlin Germany]

@easybake323

1. step
unscrew left caliper, hang it up so far
that the fender crossing hose leads only upwards
then bleed again at the left cal.

2. step
did u test if one disc is bent?
if yes , it pushes the pads every turn back into the cal. and you grab into the empty at the lever.

generally
using the zip tie trick to bleed the last tiny bubble only! works ,
when both hoses lead from pump down to the calipers.

if still a fender crossing hose is mounted the trick never will help "bleeding" the system finally.

my recommendation would be if not done yet - change to two looooooooong steel braided hoses
how?
measure the length of the RH
then order two lines
one in the length you took from the original at rh
the other 3/4" (20 centimeters) longer than the RH
watch the angles of the banjos !
(my hint : 20 and 0 degrees - the straight ones screw at the pump with a double banjo bolt and 3 (three) alu-washers)

 

[Hayabusa Wannabe]

Welcome to the forum @easybake323.

 

[Bumblebee]

Welcome and I second the diagnosis by @Berlin Germany that it sounds like a bent or out of true rotor..

Same thing happened to me on a bike once and it was a bear to diagnose...

 

[easybake323]

@easybake323

1. step
unscrew left caliper, hang it up so far
that the fender crossing hose leads only upwards
then bleed again at the left cal.

2. step
did u test if one disc is bent?
if yes , it pushes the pads every turn back into the cal. and you grab into the empty at the lever.

generally
using the zip tie trick to bleed the last tiny bubble only! works ,
when both hoses lead from pump down to the calipers.

if still a fender crossing hose is mounted the trick never will help "bleeding" the system finally.

my recommendation would be if not done yet - change to two looooooooong steel braided hoses
how?
measure the length of the RH
then order two lines
one in the length you took from the original at rh
the other 3/4" (20 centimeters) longer than the RH
watch the angles of the banjos !
(my hint : 20 and 0 degrees - the straight ones screw at the pump with a double banjo bolt and 3 (three) alu-washers)

Will the rotor be visibly bent? Like should I be able to see it just by looking? Any tricks to checking it ?

 

[sixpack577]

Will the rotor be visibly bent? Like should I be able to see it just by looking? Any tricks to checking it ?

Technically you put a dial indicator against the rotor and spin it to check the run out.
But, just checking to see if it's bent, with the front wheel on a stand, anything fixed that is put very close to the rotor, without quite touching it, so when you spin the wheel, if the rotor is bent, it will contact it at the bend.
A bent rotor that is pushing caliper pistons back as it rotates will not be difficult to see.

 

[Bumblebee]

Will the rotor be visibly bent? Like should I be able to see it just by looking? Any tricks to checking it ?

Pull off the rotors and place them on a flat surface, you'll know right away if one is bent...

 

[easybake323]

So pulled everything apart, took the rotors off and put them on a flat surface I couldn’t visually notice any warping? Put it all back together and it still doing it. The wheel spins perfectly for about half a rotation then you can feel it grab. Definitely seems like a warped rotor but visually I couldn’t see anything wrong?? So before I drop a couple hundred bucks on new rotors just wanna double check that’s gotta be the issue right? Lol. Would them being warped just a tiny amount cause that?

 

[sixpack577]

Is the wheel bent?
Even so, there would need to be hub damage.
Rotor buttons loose(they should be)?

 

[bigoltool]

So pulled everything apart, took the rotors off and put them on a flat surface I couldn’t visually notice any warping? Put it all back together and it still doing it. The wheel spins perfectly for about half a rotation then you can feel it grab. Definitely seems like a warped rotor but visually I couldn’t see anything wrong?? So before I drop a couple hundred bucks on new rotors just wanna double check that’s gotta be the issue right? Lol. Would them being warped just a tiny amount cause that?

Might be worth cleaning your Brake Rotor Bobbins (its free). Disclaimer- I don't like to generally reference Delboys videos, but the video below gets the point across. That Being said, I don't really think that is your issue. If the brakes will pump up, but not hold pressure for any length of time, it generally is a master cylinder issue. Might be air, a bad seal etc. Its for this very reason I installed a Lightech Double Banjo Bleeder on my OEM Master Cylinder, before I went to the Brembo MC, which also has a bleeder built in. It allows you to bleed the system at its highest point (bubbles rise).

 

[sixpack577]

I would rebuild calipers before I bought rotors.

 

[sixpack577]

You can also bleed a mc without a bleeder by opening/closing the line bolt.

 

[sixpack577]

I have also personally seen one brake line and one clutch line suck air, but not leak fluid(lines are 3-5 layers).
It is very rare, but does happen.

 

[JeffSyh]

I always always back bleed brake systems on everything. Get your self a nice brake bleeder. Push the fluid into the caliper up into the resvoir and then pump your brakes and bleed off the air from the bleed screw, rinse and repeat.

If you bleed from resvoir down you will be there forever!

 

[easybake323]

I have also personally seen one brake line and one clutch line suck air, but not leak fluid(lines are 3-5 layers).
It is very rare, but does happen.

Going to try the Bobbin clean first thing!! Not sure why I didn’t check that they have zero play in them.

 

[PhillipHarvey]

So I have bleed (several times now) rebuilt the master cylinder, The brake lever will get super firm and work fine but then ride it any distance it looses all pressure I can pump them up and they will work but ride any distance and they go limp. I have done the zip tie trick over night no leaks anywhere. Still has stock brake lines scratching my head not sure wtf is going on.

If you are having severe troubling then its would be even more better to consult a dealer instead of lame implementations.