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Front brake bleeding problem

5K views 11 replies 10 participants last post by  crf69 
#1 ·
So i replaced my stock front brake line with a braided one, it took forever to bleed, now it works but its not that firm, if you sqeezit it will hit the bar, am i doig something wrong, is there still air in the line?

Any help would be appreciated
 
#2 ·
yes, still air in the line for sure. I too have trouble bleeding brakes. I hear that if you get one of those gizmos that pushes fluid from the caliper up to the resevoir, it tends to get the air out. Also you can use a back massager/vibrator on the caliper and the lines to dislodge any small air bubbles that are clinging onto something. I'm sure others will give better suggestions though, I'd like to see them myself.
 
#3 ·
some bikes are harder than others...as you've found out! tap the line to help shake bubbles loose and get them to rise. make sure the master-cylinder is the highest point, otherwise air can get trapped at the high spots in the line. if there is a high spot tape/zip-tie it down tonight and hopefully that air can get out through the master over night. not sure if your master has a bleed nipple on it or not, if so bleed that in the morning as well so you're not trying to push any trapped air into the line. then just continue bleeding at the caliper until that lever firms up all nice like!
 
#5 ·
Manual on my yz250 says to-

Air bleeding steps:
a. Add proper brake fluid to the reservoir.

b. Install the diaphragm. Be careful not to
spill any fluid or allow the reservoir to
overflow.

c. Connect the clear plastic tube 2 tightly to
the caliper bleed screw 1.

d. Place the other end of the tube into a
container.

e. Slowly apply the brake lever or pedal
several times.

f. Pull the lever in or push down on the pedal.
Hold the lever or pedal in position.

g. Loosen the bleed screw and allow the
lever or pedal to travel towards its limit.

h. Tighten the bleed screw when the lever
or pedal limit has been reached; then release
the lever or pedal.

i. Repeat steps (e) to (h) until of the air
bubbles have been removed from the
system.

Now I did what it said several times and the front brake was still spongy - And it looked like no air bubbles where coming out, so I road it, so maybe now it will be better.
 
#7 ·
Most guys at shops use a vacuum actuated bleeder...this SUCKS the fluid thru the system from the bleeder screw on the caliper. some bikes just take forever to build pressure, and at lower pressures the air bubbles in the line dont move to the caliper and are trapped.

pressure bleeders also work but most bike guys steer clear of them as your putting pressure to a fluid...meaning any leaks will spray brake fluid all over your bike/floor/shop. plus when your done you have a pressurized system that will spit at you one more time when you take bleeder off.

OR...fill resevior...crack bleeder, and pull lever only 1/4 to 1/2 inch...not enough to build pressure but enough to put the master cylinder piston in a position that the trapped air can get thru to the fluid resevior. (the piston has a slot cut in it so the fluid can return to the resevior after you let brakes go...you are opening that slot with just a little action on the lever.

good luck bro.
 
#8 ·
I have a snap on power bleeder. It takes me longer to get it out of my tool box than to use it. I can do all 4 wheels on my car in about 15 min.

Once you use one you'll never go back.

One last thing is after you bleed wire tie your front brake lever all the way down to the handle bar and let it sit over night, you'll have super firm brakes in the am.


Kevin
 
#9 ·
One last thing is after you bleed wire tie your front brake lever all the way down to the handle bar and let it sit over night, you'll have super firm brakes in the am.


Kevin
What if your brake is spongy? My 98yz125 has really firm brakes, and I love it.
 
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