Front Brake Issue

[betoney]

This discussion has me wondering... 
When I flushed my brake fluid it was pretty straightforward. I didn't have to do anything special with the ABS unit. I also didn't use a huge amount of fluid, 12-16 oz at the most.
 
Is there a large volume of brake fluid in the ABS module that I didn't flush?

I'm wondering the same thing, considering the volume of the master cylinder, both calipers, and several feet of brake lines, there has to be a fair amount of fluid.   
I was talking to the lead mechanic at my local shop yesterday and he said on certain models they can hook it up to a computer (or test module) and cycle the ABS unit while bleeding, he wasn't 100% sure if the FJ had that option but is researching it for me.
 

[betoney]

Lever action and brakes are nice and firm. 
Could be overthinking this a bit... after all, we don't really fully flush any of the other fluids on the bike.

And that is why I am over thinking this as I have bled and re-bled my system and my lever is NOT nice and firm.  I have been through every part of the front brakes, cleaning and cycling caliper pistons, rebuilding the master cylinder, endless bleeding and am trying to chase down what I think is an elusive air bubble somewhere in the system.
 

[betoney]

Would there be an odd chance that o-ring inside the master cylinder isn't seated right or damaged? I realize that'd be quite a coincidence with the wheel removal. When you press the lever, do you see fluid moving about in the reservoir (fluid bypassing the piston)? Sorry... just hunting for possible causes.

FWIW,the brakes work and the bike is rideable, the brakes just aren't "great", lever pull is softer and closer to the bar than normal.  In an attempt to remedy this, I bought a rebuild kit for the MC and that made zero difference.  I then used a brand new MC and that made no difference as well.
As I posted the other day, when I tore the calipers apart to clean and cycle the pistons in and out I noticed the odd wear marks on the pads as if they were bent and had a high spot in the middle.  I just ordered new pads but I cant image that is going to solve the soft lever feel.
 

[thruster8999]

Would there be an odd chance that o-ring inside the master cylinder isn't seated right or damaged? I realize that'd be quite a coincidence with the wheel removal. When you press the lever, do you see fluid moving about in the reservoir (fluid bypassing the piston)? Sorry... just hunting for possible causes.

FWIW,the brakes work and the bike is rideable, the brakes just aren't "great", lever pull is softer and closer to the bar than normal.  In an attempt to remedy this, I bought a rebuild kit for the MC and that made zero difference.  I then used a brand new MC and that made no difference as well.
As I posted the other day, when I tore the calipers apart to clean and cycle the pistons in and out I noticed the odd wear marks on the pads as if they were bent and had a high spot in the middle.  I just ordered new pads but I cant image that is going to solve the soft lever feel.

 
I would try the EBC double H pads. They make a huge difference on the sport bike.

[BBB]

@betoney , if you put the worn pads back to back i.e. non wear side, do they align completely flat? That would show if the pads were distorted. If the backs are straight then they are either distorting under brake pressure (which is unlikely) or the disc is bent in the middle.
 
On the ABS: on my old Nissan 200SX, they bled much better after driving and activating the ABS to disturb the bubbles, several times. I did like that idea you linked to about putting a bleed point on the ABS unit.

[betoney]

@betoney , if you put the worn pads back to back i.e. non wear side, do they align completely flat? That would show if the pads were distorted. If the backs are straight then they are either distorting under brake pressure (which is unlikely) or the disc is bent in the middle. 
On the ABS: on my old Nissan 200SX, they bled much better after driving and activating the ABS to disturb the bubbles, several times. I did like that idea you linked to about putting a bleed point on the ABS unit.

When I sandwich the pads together and look at them like they are contacting the rotor from the top, the edges have a sliver of light shining through.  In the photos I posted, the contact patch is only a circle in the center of the pad and the bizarre thing is, all 4 pads have the same wear pattern.  

[betoney]

On the ABS: on my old Nissan 200SX, they bled much better after driving and activating the ABS to disturb the bubbles, several times.

I have considered doing exactly that.  Its barely above freezing today so I'm sure the road surface would be perfect for attempting this... carefully. 

[norcal616]

soft base metal plate?(what the pad media is applied to) not strong enough to apply even pressure across pad surface so it "flexes"...

[docsimple]

the reason i used so much fluid is not the ABS containing that much, its trying to get all the air out of the ABS unit. if your flushing without disassembly it is much easier.

[betoney]

On the ABS: on my old Nissan 200SX, they bled much better after driving and activating the ABS to disturb the bubbles, several times. I did like that idea you linked to about putting a bleed point on the ABS unit.

I just went out for a ride and I brought my Motion Pro speed bleeder and 8mm wrench along.  I found a large parking area with some loose dirt and gravel, I did about 5 emergency stops, hard enough to engage the front ABS each time.  I parked and hooked up my bleeder and sure enough I got 4-5 decent sized bubbles from the left side caliper (the one that comes direct from the ABS unit), the right side was bubble free.   

[betoney]

soft base metal plate?(what the pad media is applied to) not strong enough to apply even pressure across pad surface so it "flexes"...

I just ordered the Vesrah RJL pads, one of their listed Features and Benefits is: 
-"A harder backing plate than OEM brake pads for more even pressure across the pad".
 
I've heard great things about these pads, I'm remaining optimistic.
 

[timja1]

My problem is solved, Bent rotor replaced. Thanks crempel..... My bad, to much of a hurry changing tire front tire....... Thanks for all the suggestions.....

[crempel]

Glad to hear it’s fixed. I was wondering where you had disappeared to in this completely high jacked thread. ?

[betoney]

Glad to hear it’s fixed. I was wondering where you had disappeared to in this completely high jacked thread. ?

Guilty as charged.  My apologies for hijacking the thread, we had sorta similar issues and figured I would keep the group troubleshooting alive and active.   
@timja1 I'm glad to hear that your brake issue has been resolved.  Thanks to all who have taken the time to share ideas and offer help. 
 

[2and3cylinders]

On the ABS: on my old Nissan 200SX, they bled much better after driving and activating the ABS to disturb the bubbles, several times. I did like that idea you linked to about putting a bleed point on the ABS unit.

I just went out for a ride and I brought my Motion Pro speed bleeder and 8mm wrench along.  I found a large parking area with some loose dirt and gravel, I did about 5 emergency stops, hard enough to engage the front ABS each time.  I parked and hooked up my bleeder and sure enough I got 4-5 decent sized bubbles from the left side caliper (the one that comes direct from the ABS unit), the right side was bubble free. 

Bet, 
This is the first time you mentioned what means and methods you were utilizing to bleed / flush your brake system; i.e., the MP speed bleeder.
 
May I suggest you obtain a vacuum (or an inverse positive pressure type) bleeder, such as a Mity Mac (Harbor Freight surprisingly has a metal body vacuum bleed that I bought but have yet to try as I have at least 2 Mity Vacs).  I have been negative and positive pressure bleeding hydraulic systems for over 40 years unless circumstances do not permit doing so.  For manual positive displacement system pressurizing components like a motorcycle master cylinder, it is not good practice to pull the brake lever and run the piston with it's sensitive and fragile O-rings and cups through the full stroke to the end of the cylinder.  Doing so runs the piston's O-rings and sealing cups into the far end of the cylinder where it normally never ventures, and where oxidation, dirt and other nasty bits hide.  The consequence of pulling the lever and running the piston to the bottom of the bore could be ripping, nicking or tearing the O-ring with obvious negative results.  You could limit the travel of the brake lever so it does not bottom the piston but that is difficult to consistently do, and slows the process considerably.
 
Nuf said...