spongie brake lever....air or hose swelling?

[gusss]

3 months ago I flushed the old fluid.....I thought it would improve.....


Today, installed new ebc pads....
Cleaned very well pistons on calipers in order to put them in....
put new fluid and let it go down by gravity, to move old one out...
finaly brake bleeding.... pump-hold-open-close............


I still have spongie lever....

i was thinking that probably have air bubble trapped on the U on top of the fender...
or, the hose is swelling

 

[abacall]

Sounds like air. I would compare it to someone else's FZ6.

 

[RJ2112]

The bubble in the U on top of the fender is very, very hard to get out. If you are doing the standard method of bleeding the brakes, you need to 'cycle' through pump/hold, bleed, close, release.... pump/hold as quickly as you can.

Obviously, this is only possible when you bleed the left caliper (as you sit on the bike).

It helps to have a piece of tube on the bleeder, which leads into a catch bottle with some brake fluid in it. If the end of that extra line is under the surface of the brake fluid, you have less chance of sucking air back into the caliper.

When you have no air in the standard lines, the tension on the brakes will start as soon as you squeeze the lever..... when you squeeze really hard, you will feel the line 'give'.

That's what improves, with the braided lines.... the lines do not 'give' no matter how hard you squeeze.

WITH air in the standard lines, the lever will come closer to the grip than it usually does, before you start to get braking action, and you will have to squeeze the lever further to get to 'normal' braking power. When the brakes get hot, the distance the lever comes in towards the grip will become more extreme.

 

[gusss]

Sounds like air. I would compare it to someone else's FZ6.

I have, theirs is a firm lever.... mine spongie

 

[gusss]

The bubble in the U on top of the fender is very, very hard to get out. If you are doing the standard method of bleeding the brakes, you need to 'cycle' through pump/hold, bleed, close, release.... pump/hold as quickly as you can.

Obviously, this is only possible when you bleed the left caliper (as you sit on the bike).

It helps to have a piece of tube on the bleeder, which leads into a catch bottle with some brake fluid in it. If the end of that extra line is under the surface of the brake fluid, you have less chance of sucking air back into the caliper.

When you have no air in the standard lines, the tension on the brakes will start as soon as you squeeze the lever..... when you squeeze really hard, you will feel the line 'give'.

That's what improves, with the braided lines.... the lines do not 'give' no matter how hard you squeeze.

WITH air in the standard lines, the lever will come closer to the grip than it usually does, before you start to get braking action, and you will have to squeeze the lever further to get to 'normal' braking power. When the brakes get hot, the distance the lever comes in towards the grip will become more extreme.

I'll try to get the bubble out tomorrow....I just hope I have a bubble and nothing else....

I was planing on using a syringe right on the left caliper.....since i just saw today, using a clear tube for bleeding, that even horizontal tube is hard to move the bubble out....

I guess I'll just fill up a big syringe and push fluid up... since air naturally goes up........
Thanks for your input... I'm almost sure that the hoses are not failing....


oh....
forgot to mention, that on hard braking, the lever does get closer to the grip, and so I have to move it to position 4 even to 3, when I always used it on 5..

 

[Boneman]

I still have spongie lever....

i was thinking that probably have air bubble trapped on the U on top of the fender...
or, the hose is swelling

Did you "prime" the system first? Basically before you start to bleed, you pump the brake leaver for what sees like forever to build up preasure in the system/lines, then start your bleeding process.

Just follow these steps on bleeding and you should be fine: http://www.bonemanfz6.com/Manuals/Brake Bleeding.pdf

 

[gusss]

I wasn't able to do anything today....
I just un screwed the right caliper(not the left as I said before), And left it hanging just next to the other caliper.....so I had no U anymore...the line was straight and so bubbles were met to go up.....

I just don't think this got any better, I sometimes feel the lever tighter than other times....
I just hope I can do a new bleeding tomorrow, just unthighting the banjo bolts from the calipers...
any thoughts before I untight the banjo bolts?

 

[Norbert]

Could the spongie-ness be something other than incorrectly bleeding the brakes?

Maybe there's something wrong with the brake lever, a crack in the master cylinder or the diaphragm under the master cylinder cover.
Are your brake lines ok?

What brake fluid are you using? Not sure how humid it is in Brazil, I'm thinking it is. Maybe you should use a better brand.

Just throwing out some ideas, we may be focusing on the wrong thing here.

Hopefully Boneman's PDF instructions work for you though.

 

[Scorphonic]

I have the solution for you. Sponginess after putting in new fluid is not uncommon. This tip is based on the fact that there are no air bubbles in your lines and you are sure of this.

Tonight, open up the resevoir cap slightly, just to let movement of air etc..

Tie the brake lever to the handlebars, use a zip tie if necessary. Put a clean cover over the resevoir to stop dirt getting in there, and leave it overnight. Tomorrow, remove the dust cover, close the resevoir and release the brake lever. (in that order).

You "should" have rock solid brakes then...the overnight step allows for excess air in the fluid/lines to make its way out naturally...

Did the job for me perfectly!

Check this out:
Bleeding Motorcycle Brakes - webBikeWorld

 

[Boneman]

I have the solution for you. Sponginess after putting in new fluid is not uncommon. This tip is based on the fact that there are no air bubbles in your lines and you are sure of this.

Tonight, open up the resevoir cap slightly, just to let movement of air etc..

Tie the brake lever to the handlebars, use a zip tie if necessary. Put a clean cover over the resevoir to stop dirt getting in there, and leave it overnight. Tomorrow, remove the dust cover, close the resevoir and release the brake lever. (in that order).

You "should" have rock solid brakes then...the overnight step allows for excess air in the fluid/lines to make its way out naturally...

Did the job for me perfectly!

WOW! Did this the other day, and WOW, it worked like a charm! Lever is now super SOLID!

 

[Norbert]

The OP, gusss, got back to me via PM.
This is what he wrote:

THANK YOU VERY MUCH...
I figured out my problem.....it wasn't the bleeding, it was the other side from the pistons (in the caliper) that were scratched by the disc.... so the pad wasn't mounting properly...
I'll just go ahead and edit my thread....

My problem is fixed!
Thank you thank you very much for your help!!!

I'll post some pics..

He solved the problem :cheer:
He hasn't gotten around to posting the resolution to the thread, so I kinda just did it for him.

 

[Goop]

WOW! Did this the other day, and WOW, it worked like a charm! Lever is now super SOLID!

That's one of the things I love about this forum. You learn something new all of the time! :rockon:

 

[Scorphonic]

WOW! Did this the other day, and WOW, it worked like a charm! Lever is now super SOLID!

Glad it worked for you man. Makes a world of difference!

 

[gusss]

Ok....

The spongie feel went away a little... it got just stiffer...

some time ago, when mounting the tire, the pads were mounted unproperly...
Both pads were together and when braking, the back side of the pad and the calipèr pressed the disc, and the caliper was scratched...
I just had to trim down the caliper a little...


the differece between the upper and lower part on the caliper were...
2.900 cm and 2.865 cm wich is probably as thick as a hair....
Hope pics talk better than me.....


OHHHHH...
But still, Sometimes the lever is stiffer and other times it will just get closer to the grip... still needing help!!!!

 

[RJ2112]

Ok....

The spongie feel went away a little... it got just stiffer...

some time ago, when mounting the tire, the pads were mounted unproperly...
Both pads were together and when braking, the back side of the pad and the calipèr pressed the disc, and the caliper was scratched...
I just had to trim down the caliper a little...


the differece between the upper and lower part on the caliper were...
2.900 cm and 2.865 cm wich is probably as thick as a hair....
Hope pics talk better than me.....


OHHHHH...
But still, Sometimes the lever is stiffer and other times it will just get closer to the grip... still needing help!!!!

You might have a bent rotor...... if the disc is not flat and 'true', the pads have to travel different distances to reach the disc.... that can make the lever distance change, as well.

 

[Norbert]

This is a quick check so it's worth doing.
Are you sure the wheel is spinning in the right direction?
There's a cast arrow in the wheel.
Section 4-7 in the service manual.

 

[RJ2112]

Ok....

The spongie feel went away a little... it got just stiffer...

some time ago, when mounting the tire, the pads were mounted unproperly...
Both pads were together and when braking, the back side of the pad and the calipèr pressed the disc, and the caliper was scratched...
I just had to trim down the caliper a little...


the differece between the upper and lower part on the caliper were...
2.900 cm and 2.865 cm wich is probably as thick as a hair....
Hope pics talk better than me.....


OHHHHH...
But still, Sometimes the lever is stiffer and other times it will just get closer to the grip... still needing help!!!!

Guss,

The design of the calipers you have are pretty rugged, and they self adjust to even out the force between the inside and outside of the rotor. The calipers are forced to balance by riding on the pins that let the pistons push the pad on that side, and the other side is dragged into the opposite side of the rotor. The whole setup will wiggle a bit, so the sort of difference you saw with the calipers is not terribly important to how they work. The two pistons will seek their own balance, and compensate for that. The pads will also wear more on the side that hits the rotor first, compared to the edge that 'trails'.

Those sliding pins need to be free of any corrosion so the carrier can bring the off side pads into contact with the rotor smoothly.

It's important to make sure you have the calipers properly mounted to the fork, and the sliding pins are able to freely move the pads in and out.

If you have those things working properly, and you still have the issues with your brake lever travel changing and not working the same all the time..... take a straight edge you know is absolutely flat, and check to see if the rotor itself is straight.

I remember you saying you have used your brakes so hard you have smoked the pads..... that amount of heat being dumped into the rotors will make the metal expand. If there is not enough room for that to happen, the rotors will have to warp. This is why the rotors mounted in 'floating' fashion. If something stops the rotors from moving as they need to, the rotors will bend.

The pads only move twice the thickness of a human hair to engage the rotor. If the warp is even half that, it will make the lever go almost full travel.

 

[gusss]

This is a quick check so it's worth doing.
Are you sure the wheel is spinning in the right direction?
There's a cast arrow in the wheel.
Section 4-7 in the service manual.

Yes it is spinning the right way..
Thanks...

 

[gusss]

Guss,

The design of the calipers you have are pretty rugged, and they self adjust to even out the force between the inside and outside of the rotor. The calipers are forced to balance by riding on the pins that let the pistons push the pad on that side, and the other side is dragged into the opposite side of the rotor. The whole setup will wiggle a bit, so the sort of difference you saw with the calipers is not terribly important to how they work. The two pistons will seek their own balance, and compensate for that. The pads will also wear more on the side that hits the rotor first, compared to the edge that 'trails'.

Those sliding pins need to be free of any corrosion so the carrier can bring the off side pads into contact with the rotor smoothly.

It's important to make sure you have the calipers properly mounted to the fork, and the sliding pins are able to freely move the pads in and out.

If you have those things working properly, and you still have the issues with your brake lever travel changing and not working the same all the time..... take a straight edge you know is absolutely flat, and check to see if the rotor itself is straight.

I remember you saying you have used your brakes so hard you have smoked the pads..... that amount of heat being dumped into the rotors will make the metal expand. If there is not enough room for that to happen, the rotors will have to warp. This is why the rotors mounted in 'floating' fashion. If something stops the rotors from moving as they need to, the rotors will bend.

The pads only move twice the thickness of a human hair to engage the rotor. If the warp is even half that, it will make the lever go almost full travel.

the sliding pins are able to freely move the pads in and out!!! that is looking perfect...

Trying to go back on time......
The guy that changed my front tire, probably forced the rotors against the machine, when pushing the tire in with taht plate before taking it out.....

Do I have to take the rotors off before placing them in a flat surface??

 

[gusss]

I have something in mind.....

Please correct me..

If I remove both calipers, a leave them hanging, pump up the brake lever with the new pads installed until pads are closed, I should be feeling a solid lever, right? is that I just dont remember the last time I felt the lever solid....
every bike I have seen out there have a solid brake...
Can this be a master cilinder problem???


I'm just going nuts...