Brake lever fading after some turns





Yellow09

Registered
Heck, what can be said...rotors and rim are true?

Feed back into the lever means there is pressure coming back so that can only mean the pistons are being pushed in....

If you can't find it, what the others have said makes sense, go back to all stock and change one part at a time until it does what it is doing now then go back one step.
 

Johnnie Phatt

Registered
If it is trouble with a bleed I have only two suggestions left
Put the fluid in through the caliper bleed screw and push it up to the M/C and as a last resort get a small hand sander with a rubber pad on the base and place it lightly against the caliper and turn it on. The vibration may/does cause any bubbles to rise up. If the lever is pushing steadily back the fluid is heating up and expanding. Which unfortunately is the direct opposite of an air bubble I would think I have seen badly adjusted disk brakes bring a bike to a halt through fluid expansion. But that does not seem to be the case. I'm still stumped
 

ottafish

Registered
Let's look at this logically.
You say you have changed the calipers, m/c, lines, pads and fluid quite a few times and in different combinations.
Early on, you say: " I had never had any issues until I upgraded the whole brake system"

So you have had the time and the money to keep fluffing around swapping aftermarket bits but seem to be chasing your tail. ( which by the way you are way more patient than me by now)
Until you go back to a factory stock system and make sure it's working 100% as it should, you are chasing ghosts. You "may" have a problem that is affecting the brakes indirectly, not the braking system itself. No idea what it may be, but it's looking more likely based on what you've changed to find the problem.

But until you get a baseline as the bike was built, you will be going around in circles getting more and more frustrated.
 

fallenarch

THE SLOW RIDER
Registered
The brake system is an independent system. Going back to the OEM systems tells him nothing, other than maybe the problem is in some of the parts he has, which is a very safe assumption anyway. The problem the OP has described cannot exist outside the braking system parts IMHO. So he's missing something, a part or hydraulic line that is causing the issue.
 

ali123

Registered
The brake system is an independent system. Going back to the OEM systems tells him nothing, other than maybe the problem is in some of the parts he has, which is a very safe assumption anyway. The problem the OP has described cannot exist outside the braking system parts IMHO. So he's missing something, a part or hydraulic line that is causing the issue.
plus a thousand.... the OP missed something..... ORRRRR this is a problem that exists solely in his head
 

Yellow09

Registered
The brake system is an independent system. Going back to the OEM systems tells him nothing, other than maybe the problem is in some of the parts he has, which is a very safe assumption anyway. The problem the OP has described cannot exist outside the braking system parts IMHO. So he's missing something, a part or hydraulic line that is causing the issue.
I still stand behind my previous post.

Everyone is stumped, I believe the only way to perhaps resolve what is going on is to back-track the mods and hope whatever caused the issue can be resolved..

"shrug" don't know but hope something like would work. If bike shops can't get to the root of the issue, what's next?
 

ali123

Registered
I still stand behind my previous post.

Everyone is stumped, I believe the only way to perhaps resolve what is going on is to back-track the mods and hope whatever caused the issue can be resolved..

"shrug" don't know but hope something like would work. If bike shops can't get to the root of the issue, what's next?
trade it in.… or ride it into the east river and file the claim.... lol... hell find the issue, and in the grand scheme of things this is minor.
 

shade

Registered
Nope echo what others have said.
Go back to stock everything
Validate it works.
If it works
Change one thing at a time
First calipers - validate it works
Brake lines - validate
Master cylinder
Etc etc

That will be IMO the only way to fully validate everything.
 

guitarrasa

Registered
Heck, what can be said...rotors and rim are true?

Feed back into the lever means there is pressure coming back so that can only mean the pistons are being pushed in....

If you can't find it, what the others have said makes sense, go back to all stock and change one part at a time until it does what it is doing now then go back one step.
Rotors are ruled out as I already tried with the Original ones, in another hand there is a small chance that the problem might be coming from a bent rim? I didn't have any accident with my bike. The only thing I can think of its that the rim got damaged when the mechanic first installed the previous Brembo calipers with the wrong spacers, After going for a ride and try the brakes I had to take the bike back to the work shop as the disk were rubbing against the calipers to the point of almost making the bike fully stop. Would that have been enough to bend a rim?
 

Yellow09

Registered
Rotors are ruled out as I already tried with the Original ones, in another hand there is a small chance that the problem might be coming from a bent rim? I didn't have any accident with my bike. The only thing I can think of its that the rim got damaged when the mechanic first installed the previous Brembo calipers with the wrong spacers, After going for a ride and try the brakes I had to take the bike back to the work shop as the disk were rubbing against the calipers to the point of almost making the bike fully stop. Would that have been enough to bend a rim?
I honestly don't know if that would bend a rim...it might makes something out of true....maybe the shims aren't exact and the calipers are slightly out of true....

It sure seems like something is slightly out of true because of the lever feed back....something is causing pressure in the system and being out of true is the only solution I can think of.
 

Yellow09

Registered
Those calipers have to be perfectly aligned...even if one is out by a mm either on top or bottom, it could cause this...if you had the issue you describe with the bike almost stopping because of improper alignment, I'd start there.

I'm just spit-balling though..
 

guitarrasa

Registered
Those calipers have to be perfectly aligned...even if one is out by a mm either on top or bottom, it could cause this...if you had the issue you describe with the bike almost stopping because of improper alignment, I'd start there.

I'm just spit-balling though..
Right, but thay was because of the wrong spacers size. Once I changed them, rotors would turn freely
 

guitarrasa

Registered
I reckon the calipers are not aligned correctly, interested to see what the solution will be, it's hard to diagnose issues with just a description and not actually seeing the set up in person....
At this point anything can be an option, but I guess if the calipers were not aligned properly ai would know. I mean, how can also the original calipers not be properly aligned?
 

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