Urgent help!!! - Bleeding brakes

[COP_B8]

I am trying to get my front brakes bleed in order to go and get a warrant tomorrow however it aint bloody workin!

- Brakes were completely stripped during my rebuild
- They have been correctly reinstalled
- I have now bleed through (Pump brake, release nipple valve thingy on calliper then tighten then release brake lever) for over 45minutes and still no braking.
- Brake fluid is coming out of the nipple
- CBR400RR with aftermarket braided lines.

Do i need to be using a special tool, i seem to remember something about pressurizing it when running fluid through from completely dry?????

any ideas????

And just to beat Poos to it......Getting a Suzuki is not the kind of idea i was looking for.....

[KLOWN]

there is a thread on here to tell you how to bleed brakes properly or if you have air bubbles trapped under the brake cylinder. i'll have a look and repost if I can find it.

[KLOWN]

try this (cut and pasted from different thread) from denniso

The fastest way I've found to bleed bike brakes is to get a large syringe from a vet supply bout 60ml dont want the needle , connect to this a suitable hose that will go onto the bleed nipple fill this with brake fluid (suck it out of a new clean bottle of good brake fluid , dont mix silicon & mineral fluid ) make sure no air bubbles in syringe & connect to brake nipple , loosen nipple & push fluid in , this pushes out the old fluid and air , make sure that the resivar dosent overflow ( take off top beforhand and clean out old fluid from it , keep an eye on the level as you pump in the new fluid) As long as everything else is good this will get rid of any air bubbles well because you are pushing the air the way it wants to go , up .Dont forget to tighten up the bleed nipple before you take off the hose from syringe.

[COP_B8]

Cheers, I will give that a go, dont have a syringe but a small bottle should do hopefully.

[KLOWN]

or this .. from bob smith

I've just gone and cleaned my brake parts out and put some new grease on them a few days ago and went to bleed them. Now the rear brake was easy enough, but when I went to do the front one, I kept on pumping the brakes but they just wouldn't pressurise (read: it felt spongy and it didn't go away when the brake pads moved all the way to the and they were in the right position) no matter how much pumping and bleeding I did.

I wasted several hours doing this, did some search on google and here and found out that problem is most like air bubbles stuck just below the master cylinder.

Now all the posts suggested that I would need a pressure bleeder to force the brake fluid from the bottom to get the air out and should take it to the shop but of course being stubborn I couldn't do that. (besides the fact that I've got no money...)

So here's what I did and fixed my problem within 15 minutes (wish I thought of this earlier) If you're having trouble of no air bubbles coming out from the calipers (ie only brake fluid coming out suggesting that the calipers are bleed of air) but the brakes still feel spongy here is what you can do:

1. First bleed the brake as much as you can.
2. When you've bleed the brake so that the slave cylinders (the brake caliper) is full of brake fluid (you can tell by when you're bleeding that only brake fluid is coming out) get a G-clamp and start pushing the pistons back.
3. Hopefully that should force the brake fluid up the line to the master cylinder and should get that airbubble out. Becareful that you don't spray yourself with brake fluid as you do this (picture you croutching down pushing the pistons back then the air bubbles come out the top and you had too much brake fluid in the master cylinder and it goes all over the place... not fun)
4. Now pump the brake and let the pistons out a bit then press them back again and repeat this a few times until the pistons come out [insert a word that I can't think of here... (well?) ] with the pumping of the brake lever (before you start pushing the pistons back to bleed the line and the master cylinder you'll see that pumping of the lever doesn't push the pistons out as well as it should, well now it should push them out quite easily)
5. you're done, reassemble the brake caliper then bleed the brake as per normal.


Now I've written this with my limited knowledge of how the brake systems work and from my experience with the brake bleeding nightmare. Take into account that I've only bleed 4 brakes before if anyone can suggest a correction to these please let us know!

I wrote this because I wasted 6 hours and almost a whole bottle of brake fluid trying the bleed the front brakes, hopefully this should save some time for another person with similar problems.

[Sam I Am]

my old fzr i had to bleed with the caliper unbolted and turned up side down so the nipple was pointing up that seemed to work for me

[imdying]

The master cylinder has been empty, and it can't pump air, so you'll need to prime it. Some posts on that around here somewhere.

[KLOWN]

The master cylinder has been empty, and it can't pump air, so you'll need to prime it. Some posts on that around here somewhere.

was going to copy and paste your post about it but just thought after the other two I copied and posted that was enough.

[KLOWN]

here you go... from imdying

If you've rebuilt the master, it has air in it. They're very simple, and can't self prime themselves.

Take the hose off of the top, hold down the lever. Put your finger over the outlet, release the lever. Pull the lever in, let your finger off briefly to let the air/fluid out. Let the lever out, and it'll suck fluid down, instead of drawing air back up the inlet. Repeat that action a few times, and you'll have a good fluid flow. Hook the line up again, and you'll have a much better chance!

What you're doing by that action, is essentially filling the guts of the master back up with fluid. Like an oil pump in the motor, it can't pump air, only fluid.
__________________

[KLOWN]

just to add.

the search engine is your friend. all i searched for was brake bleeding and there is plenty more information out there

[merv]

I'm not far from you so if you are still having trouble with this I could come and have a look tonight. Unless your master cylinder is stuffed this should be an easy job. I recommend just having a small plastic tube attached to the bleed nipple and a catch bottle under it and other than probably a 10mm ring spanner to loosen and tighten the nipple all you need is another pair of hands which I can provide and a bottle of fresh fluid to top up the reservoir.

PM me if you need help giving me your contact details.

[COP_B8]

All done, thanks for your help!

[Freebird]

I also live in Whitby and I'm an engineer so if you ever need a hand with anything like that give me a shout :yes:

[KLOWN]

All done, thanks for your help!


which method did the trick?

[COP_B8]

put brake fluid in an air tight bottle with a pipe and force fed the fluid in (syringe method) after that only took about 5min to finish bleeding them off and they feel better than ever.

[KLOWN]

put brake fluid in an air tight bottle with a pipe and force fed the fluid in (syringe method) after that only took about 5min to finish bleeding them off and they feel better than ever.

good stuff.