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

[gusss]

Took my master cylinder apart, found everything ok!
I even washed with water and then air dryed!
I then lubricated everythi with brake fluid a kindly put everything back in place...

Since there was only supposed be new air from the banjo bolt and up....
I didn't bleed the brakes, I just pumped the lever....

In order for the liquid not to jump out to my eyes or to the paint, I put a small paper towel on top of the reservoir...
Since slowly I was getting a lever, but really slowly...
I put a little rectagle cut see-through plastic piece of plastic bag....
I put it inside of the reservoir, to prevent liquid from jumping, and to be able to see bubbles comming out.
SURPRISE!!!!!!!

It's been 18 hours of pumping, and now I have a 80% stiff lever...
Boing boing is going away...
There are thousands of miniature bubbles caught right under the pice of of plastic paper bag I used. If it wasn't for this, They wouldn't have been seen.
Thousands and thousand are still comming out, and you can see change in the lever probably every 3 hours...

I tryed bleeding through the upper banjo at the master cylinder (just like you bleed calipers) No good...

It looks like the micro bubbles are stuck to the walls of the hose, and only when pumping (since the hoses expand and contract) (I think), bubbles are getting loose....

To get to this theory... I used a seringe, and sucked in some fluid with this micro bubbles... I was hitting the clear plastic, and the bubbles woudn't move...only bigger bubbles would!
The only way of moving the stuck to walls bubbles was to chase with a bigger bubble the smaller ones...
And besides, the speed upwards from these bubles through the liquid is 2"/30 sec...
I'm just happy now, but I'll get to 98% and let you know!

 

[TownsendsFJR1300]

Are you bleeding strictly at the banjo bolts or the nipple atop the brake calibers?

The nipple at the top is designed for bleeding. If you do not bleed from there, sooner or later, you'll still have air in the system as its higher than the banjo bolt (on the brake caliber)

 

[gusss]

Are you bleeding strictly at the banjo bolts or the nipple atop the brake calibers?

The nipple at the top is designed for bleeding. If you do not bleed from there, sooner or later, you'll still have air in the system as its higher than the banjo bolt (on the brake caliber)

at the calipers, used the niples.....
at the master cylinder the banjo bolt...

 

[gusss]

I am happy to tell you friends, my lever is at 90%


I'll keep on posting....

 

[RJ2112]

You should probably invest in the syringe, to reverse bleed the system.

Instead of pumping the fluid 'down' the line to the calipers, and trying to do that fast enough to push the bubbles out, the syringe method pumps fresh fluid in from the bottom, and into the reservoir at the master cylinder.

As the fluid is moving up hill, it's much more likely to 'carry' the bubbles out, into the reservoir.

It's good to hear you cleaned the seals on the master, and that seems to be allowing you to apply pressure to the system. That is as it should be. I have to wonder why you are still seeing small bubbles.....

I wonder if you have a leak at the calipers? Is everything spotlessly clean, and there is not wetness anywhere?

 

[gusss]

You should probably invest in the syringe, to reverse bleed the system.

Instead of pumping the fluid 'down' the line to the calipers, and trying to do that fast enough to push the bubbles out, the syringe method pumps fresh fluid in from the bottom, and into the reservoir at the master cylinder.

As the fluid is moving up hill, it's much more likely to 'carry' the bubbles out, into the reservoir.

It's good to hear you cleaned the seals on the master, and that seems to be allowing you to apply pressure to the system. That is as it should be. I have to wonder why you are still seeing small bubbles.....

I wonder if you have a leak at the calipers? Is everything spotlessly clean, and there is not wetness anywhere?

I would say that everything in the master cylinder was ok before I cleaned it...
I just had these micro bubbles in the lines......
But they are only visible putting the clear plastic in the reservoir...

And yes, everything is clean, no leaks!!!!

 

[seb101]

Hi,
Two days ago i swaped my front brake pads with new EBC pads, when i was cleaning the callipers and pushing the pistons so that i could clean them perfectly one of them poped-out :/ since i was planning to bleed-cahnge the brake fluid i didn't bother me too much.

I connected the tube between the bleeding niple and the syringe (with brake fluid in it) and did the procedure of pressing lever-opening valve on the niple-closing valve on the niple-release lever, i did it on both sides but the lever feels little bit spongier, it was solid before the brake swap-bleeding procedure.

Since them i've been googling alot and i came across couple of methods and tips, besides the zip tie holding lever down (sounds good, but im wondering about all the water getting from air into the resvoair during the night) the method of reverse bleeding using syringe.

Has anyone tried that? it would work abotu the same as multivac but it's way cheaper.

Get a great big monojet syringe. Agricultural supply places and feed stores have
them. I have one that holds 300cc, which is about five times what your brake system
holds. You want to connect this to your bleeder nipple, so get clear aquarium tubing
or clear PVC tubing at the hardware store and whatever connectors you need to
connect the syringe to the nipple.

Fill the syringe with fresh brake fluid, and fill the connected hoses with fluid too.
Attach the hoses to the bleeder nipple. Get ALL the bubbles out of the tubing and the
syringe. There can be air at the plunger end of the syringe as long as you hold it
plunger-up and don't squirt so far that it enters the hose.

Once all the bubbles are out of the tubing and syringe, crack the bleeder nipple and
gently plunge new fluid into the system. It should push all the old fluid, and your
bubbles, out through the master cylinder. The master cylinder resevoir will over flow,
so have a helper there to suck it down with another syringe, or have a bunch of rags
there to catch the overflow, or have stuff under the master cylinder that you don't care
about.

Some calipers have chambers that can have high internal cavities that will hold air
the way air will stay in an inverted glass underwater. The bleeder valve SHOULD be
the highest point on the inside of a caliper cavity, but it sometimes isn't. So, as you
are plunging the fresh fluid into the caliper, without letting the hose come off the
nipple, roll and rotate the caliper around so that any internal trapped bubbles can
make their way to the bleeder valve and on out through the brake hose and out the
master cylinder resevoir.

If you run out of juice in the big supply syringe while you're doing this, just shut the
bleeder valve, pull the plunger out, add more juice to the supply syringe and re-insert
the plunger. If you do this right, no air will enter the hose at the bottom of the syringe,
and you can continue to pump juice through the system.

After you've pumped a bunch of fluid through, shut the bleeder valve and button up the
master resevoir. Clean everything up and re-install on the bike

Another TIP i've found, is:

Mine too. Another thing to remember is to wedge a screw driver between the pad and the rotor so the piston is pushed all the way into the caliper. It will make it faster to get the air out.

I would rather put something from wood not to scratch the pistons but the main point is to push the pistons back into caliper so there isn't much room-place for air left.