bleeding brakes

Ish · 10 Apr 2014 at 19:11

Hi

I'm trying to sort out the front brakes on my Ninja.

I have new lines & pads. The calipers have been cleaned up and all pistons move freely.

I just can't get a solid lever. I have the lever on position 1 and it takes half it's travel before the lever goes solid.

I have bled using a one way valve and I'm getting clear bubble free fluid coming through.

What else should I be trying?

wazza300 · 10 Apr 2014 at 19:15

are you pinching the short tube that goes to the res? keep pinching it with thumb n finger you'll see tiny trapped air bubbles float out

and are all the pistons moving out? not just one side?

they are a bit **** though tokicos,even once refurbed

Dogbreath · 10 Apr 2014 at 19:17

Try bleeding them manually by cracking the bleed nipple open and shut as you squeeze the lever. With a one way valve you can get air leaking through the bleed nipple threads.

You can also try tapping the calipers with a soft hammer or lump of wood to dislodge any bubbles that may be clinging on.

Ish · 10 Apr 2014 at 19:24

I'll give that a try. I've also had it suggested that I should crack off the banjo at the master cylinder and bleed that first.

wazza300 · 10 Apr 2014 at 19:28

pinching the tube to the res worked for me,you'll be surprised how much air is in there (keep pinching as your pumping the lever)

SPG · 10 Apr 2014 at 19:46

Leave the cap off the brake resevoir, and use a zip tie to pull the lever back overnight. Worked a treat on my ninja. Make sure you tap the the lines a little as well.

Dogbreath · 10 Apr 2014 at 19:56

SPG said:
Leave the cap off the brake resevoir, and use a zip tie to pull the lever back overnight. Worked a treat on my ninja. Make sure you tap the the lines a little as well.

Keeping pressure on the lever compresses the air and eventually causes it to disperse into the fluid (like CO2 in a fizzy drink). It's still there though, and a heat cycle can release it again.

What is leaving the cap off supposed to achieve other than allowing your brake fluid to absorb moisture?

.one. · 11 Apr 2014 at 14:02

Many tricks to bleeding brakes, we use the method Dogbreath suggested to start with always have but if that fails then move on to bleeding from the master cylinder by just fetling the lever done many an awkward brake this way.

And have also as a last resort done the over night method and must say never had an issue with air coming back ever.

Saying that I will take the opinion on board something to take into consideration.

ps. I am not sure if the word fetling is a real word but get the idea

pieman109 · 12 Apr 2014 at 22:22

Been doing this for over thirty years and never fails. Where air usually gets trapped is in either one or both of the calipers right at the area above the banjo fitting in the caliper itself. Sometimes no amount of bleeding gets rid of it and the only way to get the air out is to take the caliper off the fork leg and "tilt" it so the banjo fitting is the highest part of the caliper relative to the ground. that way while bleeding, the air has an unobstructed path to the master cylinder and then to atmosphere. also when bleeding, use a clean oil can full of brake fluid with a small diameter hose over the spout and the other end with a good tight fit over the bleed nipple, then you can pump the fluid into the caliper/ brake lines under a slight bit of pressure. Just be sure to keep an eye on the open master cylinder as the fluid will fill it up very quickly and could overflow and in extreme cases, if the brake fluid is pumped through too vigorously, it can actually "squirt" out of the brake line thats connected to the master cylinder and cause a right mess so go easy with the oil can.