Brake Bleeding

[Coyote]

Just went to the gargre this afternoon, and tryed to fill the lines with brake fluid then bleed them, only problem is the fluid doesn't seem to be going down the brake lines. I'm pretty sure I've done everything right, lossening the bleeding caps (not sure of proper terminoligy) and then filled the resevoir and pumped the brake lever. I got a few bubbles appearing in the resevior but then nothing was happing. What the hell am I doing wrong?

[vifferman]

Air lock.
The fluid can't run through, because there's air in the lines trying to go up, while the fluid's trying to go down.
It will start working after a while, but "a while' could involve an awful lot of pumping. You can speed it up by tapping the connections with a small spanner to encourage the air to rise, and also cracking a union to let the brake fluid run down can help too. (Be careful, as this is messy, and you could also let more air in.)

[Coyote]

Air lock.

Now whats this airlock?

[Coyote]

Is the air lock part no. 3?

[RiderInBlack]

This the same as I do for brake bleeding (from this old thread "Bleeding Hydraulic Clutch":

"Roxanne" has a Hydrolic clutch lever. I had to replace her master cyclinder kit for it. Put the kit in the wrong way at first and wonder why it was not bleeding properly (it was sucking not blowing) Once I put the kit in the right way it was only just a bit harder to do than the brakes. This is how I go about it:
Once I have freash fluid in the whole line, I recycle the fluid back in the reservoir (using the same method of bleeding as in the brakes). I do this by having a bleeding hose long enough to go from the slave to the master (putting the end in the reservoir fluid). I keep recycling until I can not see any fine bubbles coming out of the hose.
By using this method I stop air being sucked back in the system, use less fluid, and can see when all the fine bubbles have come out. This eliminated power bleeding for me

Hope it helps.

[RiderInBlack]

The term "Air-Lock" is not a part. It is where air trapped in a fliud fulled line stops the flow of the fliud. Part 3 is the bleed valve.

[saiko]

Tell me about it - I just spent 2 hours bleeding my brakes on my VF (dual caliper) & the bastards seem no better than before! At least the fluid's cleaner! Sod it, I'll do it again next weekend - time to stop when you start throwing things around in frustration.

[Coyote]

The term "Air-Lock" is not a part. It is where air trapped in a fliud fulled line stops the flow of the fliud. Part 3 is the bleed valve.

So it'll jst require a hell of alotta pumping of the brakes to dislodge this air lock?

[Ixion]

So it'll jst require a hell of alotta pumping of the brakes to dislodge this air lock?

Maybe not. Trouble is if you have an air bubble, air is compressable. So when you pump, it just compresses the air in the air bubble. When you release the lever, the bubble expands again. Repeat ad infinitum. Use RIB's method of a long tube from the bleed valve back to the reservoir. That way you move the air bubble round the loop until it pops out in the reservoir.

[saiko]

Sorry - this is interesting & I'll try it myself - but I don't see how, if there is an air bubble which is hard to force through the line down to the bleed valve, how attaching a line back up to the reservoir - high up on the handlebar will work, unless it is something to do with the system then being fully sealed - i.e. rather than just bleeding from the valve into a container.

Would someone please explain the procedure in baby steps?
Thank you.

[Coyote]

Would someone please explain the procedure in baby steps?

Thats what I need, I can't be bothered thinking right now

[saiko]

Yeah, or maybe beers & food for a live demo!

[wildcat_lgf]

Or you could have a look at this thread...I had a similar problem with air in the lines.

http://www.kiwibiker.co.nz/forums/sh...brake+bleeding

But I just cracked open the top nut where the special bleed valve thing mentioned in the thread would go and it bled perfectly.

First pump the lever a couple of times, then hold the lever in...crack the banjo bolt thing up by the reservoir (where the rubber brake lines go from), let the air rush out...tighten the bolt. Then pump the lever, hold it in, open the banjo bolt letting air rush out. Close the bolt, release lever, etc.

It worked well for me, yours might be a different problem but hey it might be worth a try.

[TwoSeven]

There is an airlock inside the piston. You need to remove the hose at the top and allow fluid to move thru the piston.

A vacume brake bleeder is the easiest method, just sucks all the muck thru the system.

[BNZ]

I bled mine a month or so ago.... Attached clear PVC hose to the bleed valves, removed reserviour lid (made sure it had plenty in it) and squeezed the handle until there was sufficient resistance. While squeezing the handle loosen one valve slightly and the handle will lose all resistance as fluid is pumped out into your clear tube (that leads to a container!). Make sure you then close the valve asap before releasing the handle. I ran through this process alternating caliper until i had clean fluid coming out the bottom.