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Post by 90GTVert on Feb 16, 2010 13:35:23 GMT -5
Today I had to replace a brake line on a 150cc 4 stroke. (1st time bleeding a scooter brake for me) The brake line replacement was easy but when I went to fill and bleed the system I squeezed the lever and opened/closed the bleed valve a hundred times and the fluid level in the reservoir never dropped so I was getting frustrated. I decided to remove the lever and push the plunger with my finger which made the plunger push in farther and that worked to get the fluid moving but it's hard on your finger so after staring at it for a few minutes it hit me: The lever was hitting the handle bar limiting the plunger travel! So I put the lever back on and then I slid the entire handle assy out to toward the end of the handle bar so the brake lever was hanging out in space and tried it. Voila! The lever wasn't limited in it's travel by the handle bar and the brake was bled in less than 5 minutes! Hope this helps somebody. I was bleeding my Derbi brakes the other day and encountered a similar problem. Whatever works best for each individual situation is appropriate. What worked for me was making very, very small strokes (1/8 to 1/4 inch at the end of the the lever ball) to get the fluid moving while leaving the caliper bleed fitting open. I just kept making those tiny strokes until no more bubbles came out ( of the reservoir). In the past I have taken things apart as you did. This time I avoided that. I changed my rear pads too. Drained the fluid out, cleaned out master cylinders, filled with new DOT 3 brake fluid, than started the bleeding process. The brakes will be dead at start( meaning no brake at all). After pumping brake 3 times, place a bungy cord around the brake lever, than go to rear and open brake line, it will let fluid and air out. Repeat this process until you feel the brake has sufficient braking power. The bungy cord acts like a hand, constricting the brake as you bleed the brake. Now when I first started bleeding brakes by myself, I would fill master cylinder, put on lid to master cylinder and pump brake lever, put bungy cord around lever and handle grip, bleed open line to let air out, close line, pump brake 3 times, put bungy cord on lever and handle bar grip, ect.. repeating, and repeating. Every third time in the procedure, I would take off master cylinder lid and add a little brake fluid. Put lid back on and repeat. It gave me a lot of braking power, but this method ruins the screws if taking off and on. I bought new screws at the local hardware store. They have small metal screws that are metric. when it comes to filling break lines i get the caliper extended out and close the bleeder and slowly compress the piston to push fluid up the line it usually gets enough fluid in and through the lines to where you can hose bleed the breaks to remove the last of the air  |
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Post by JEGZ on Oct 7, 2013 14:54:07 GMT -5
I bled my brake fluid one time and a few weeks later was surprised to see some of my dash crumbling away. You may wonder what happened. Well folks brake fluid turns out to be very corrosive, so the first thing you may want to do is get a funnel so you don't drip that crap anywhere. Alternatively you could unattach your brake and attach it to a straight piece of bar and stand away from the bike altogether.
Next you will want to get a cheap brake bleed kit from harbor freight. No not the one with the pump, the $5 one under that. Alternatively you could just get a hose from Lowe's that will fit your bleed hole, and drain it to a pie tin or something you don't need.
Next you will attach the bleed kit to the bleed hole and unscrew the bleed screw. Maybe a few drops or drizzle will come out.
Unscrew your bleed plate located on the front brake assembly or sometimes both, whichever one you intend to do first. Next you will give the brake a few squeezes, until the reservoir is almost empty. Then you will take your funnel and pour some dot 3 brake fluid in, making sure not to spill any over the sides of your reservoir. Repeat steps 1 until you have a nice steady flow of fluid through the3 tube and your sure your brakes are flushed.
Immediately tighten the bleed screw, top off the bleed reservoir almost to the top, and carefully replace reservoir plate. You should feel a tight resistance when squeezing the brake. Wipe off any over spill with soapy water, and enjoy the ride.
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Post by geoffh on Sept 17, 2015 15:28:17 GMT -5
If your struggling to get that "solid as a rock" feeling to your system try this, attach the tube and syringe to the brake nipple and either push fluid up into the system or pull the fluid down from the master cylinder.Pulling the fluid down works best for me,just go slow and steady.It,s better to purchase the syringe and tube before you need them   cheers geoff |
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