I'm in the middle of a bar swap and have to change the front brake line. Whats the best way to bleed the air out of it..? thanks for any help,Brian

 

Found on the net but this is how i do mine.

Brake fluid will eat away at plastic and paint, be sure to cover any paint or plastic that may get splashed with brake fluid. Wipe any spilled fluid with the rag and lots of water.
Step 1: Make sure you have the tools to bleed your brake fluid. The tools you require will vary, but generally this is what you will need:
A. Wrench/Spanner (average 10mm)
B. Brake bleeding kit (rubber fitting, clear hose, small container)
C. Brake fluid overflow container (to put the brake bleeding kit small container in)
D. Rags
E. Brake Fluid (check what type of brake fluid you need for your bike. e.g. DOT 4/5). Make sure to buy enough brake fluid in the DOT type you require. (500ml should be more than enough).
Step 2: Attach the brake bleeding kit to the brake fluid nipple located on the brake caliper.
Step 3: Loosen the nipple so the fluid is free to flow down the brake bleeding kit tube and into the small container
Step 4: Remove the master cylinder cap (top) so you can monitor and refill more brake fluid into the master cylinder as you bleed the brakes.
Step 5. Pump the brake lever so the old/new brake fluid is forced through the tube into the brake bleeding kit fluid container
Step 6: Keep the volume of the master cylinder constant (near full) as to not have it empty. Keep pumping on the brake lever until the fluid coming out is clear (rather than the old brown/black colour).
Step 7: Once all the tiny air bubbles are gone hold pressure on the brake level and re-tighten the brake fluid nipple to close it off.
Step 8: Replace the master cylinder top cover.
Step 9: Remove the brake bleeding kit from the cliper and use the rag with water to clean up any spillage.

 

And it takes just about forever. I've done two different bikes in the last couple weeks, and it took about a half hour each. Your hand will be tired of pumping by the time your done.

 

I was questioning this as well. I just changed bars and I was bleeding the brakes like i do in the car.
Attatch a hose to the caliper then into a bottle
Once fluid is comming out of the hose into the bottle, i know the fluid has made it from the master cyl to the bottom of the hose.
I pump the brake handle to build pressure then hold
I open the caliper bleeder screw and squeeze the brake handle till it reaches the grip then while holding the handle close the bleeder screw.
Repeat many times.

I did this about 20 times but still feel the front brake is soft and spongy.

Is it better to fill a bottle with brake fluid, run the hose from bleeder into it, making sure the hose in in brake fluid. Then just pump the handle slowly. It wont suck air since the hose is in the fluid.

I have always just done the pressure way. Let me know what works best. SInce mine are still spongy.

 

As said above, it takes awhile to Bleed the Brakes, so don't Panic. I use a Handheld Vacum assist to Bleed Brakes. they cost about 30.00 Bucks and usualy comes with all the Conectors and Hoses. Don't remember where I got the Last one from. DO NOT take off down the Road and think everything is Fine with the Brakes when your finished. Be cautious at first Ride.

 

Harbor Freight has the vacume assist brake bleeding system, $25... works great.

 

Fogot to say when i am finished i pull the brake lever in so it is very firm leaving the master cylinder cap off and put a zip tie round the lever and bars overnight keeping the pressure on for 8-10 hours i find that it forces any small air bubbles up never had any issues then with a soft brake lever.

Regards Brad

 

I can relate ...

.

 

I've done mine the last few times the exact same way as fat bob brad and it only took a few minutes. I've also flushed out my rear brake line and it also only took a couple minutes.

 

Just did this process, and the only thing I'd add (which I read here) is take a screwdriver handle and tap lightly on the line up and down to help remove any trapped air.