Bleeding Brakes

Kaph · Nitrous Nuisance Joined: 03 Oct 2009 Karma :

This is pretty much my fault here.

Came back from a ride, line from master cylinder down to rear brake had come off, and was dripping brake fluid over the wheel.

Obviously air would have got in, so decided I'd have to bleed it.

Unfortunately, my error, we didn't really look into the specific guidelines until after things had gone wrong.

We just put the tube onto the bleed nipple, put t'other end into a jar, undid the bleed nipple and pumped the brake, until no more came out. Obviously, this means the line had fallen before the minimum point(we didn't know about this at the start). So we put the new stuff in, pumped the brake to try and get it in, and none of it was going in, ie. the master cylinder level didn't decrease.

Anyway, we read up on the proper procedure and realised we'd cocked up. Everywhere simply states NOT to let the level fall below minimum.

I've just been out and tried the proper way (as I understand it).

1) Wrench on bleed nipple
2) Tube on bleed nipple
3) Other end into jar, with some brake fluid in so it sucks that back up instead of air
4) Let out bleed nipple as I push down the brake
5) Hold pressure until bubbles stop coming
6) Retighten bleed nipple
7) Release pressure

Now bubbles come out, but the master cylinder level still isn't dropping.

Have I completely c*cked it up? I understand it's probably easier with a one way valve, ordered a kit off of eBay but don't know if that'll make much difference to the problem, just make it easier to bleed.

Thanks, sorry for the looong post.

tl;dr let brake level fall below minimum when bleeding, didn't close bleed nipple, put new stuff in, new stuff wont go in.

That_Hornet · World Chat Champion Joined: 23 Apr 2009 Karma :

Sorry, was there a question i that? Confused

As for bleeding brakes,

https://www.diytools.co.uk/diy/Images/DB_Detail/_35771_142236.jpg

I use that, Just plug it in and start pumping till the air is out, then tighten the nipple. Simples.

But another way i found is to use a syringe, Big one and connect it to the bleed nipple and suck. Thumbs Up

Don't forget to bleed the master cylinder if you not getting pressure.

steven_191 · Nearly there... Joined: 31 May 2009 Karma :

one man bleed kits work fine. i did mine the other week. took maybe 10 minutes. just make sure you have some fluid in the bottle so it doesnt suck any air up and it'll all be gravy

Kaph · Nitrous Nuisance Joined: 03 Oct 2009 Karma :

That_Hornet · World Chat Champion Joined: 23 Apr 2009 Karma :

As for filling it up, Just leave the top off the reservoir. Then when pumping the pedal, just keep an eye on the reservoir level, Just a matter of looking.

As for bleeding the master cylinder, keep it topped up and undo the banjo bolt a little. (I can't quite remember if you pump the pedal, keep it down and undo then banjo, then do up, then let off the pedal) Confused

Think so, sure someone will come along soon and correct me if im wrong. Thumbs Up

HTH

Kaph · Nitrous Nuisance Joined: 03 Oct 2009 Karma :

MaybeGuy · Super Spammer Joined: 12 Mar 2007 Karma :

take the end of the hose off and suck it through.
tried and tested method
____________________
Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!! Mr. Green

Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

cb1rocket · World Chat Champion Joined: 30 Jan 2010 Karma :

I use a big syringe and pump the fluid in from the caliper through the nipple, that way all the air is going up instead of trying to be pushed down.

air is lighter than brake fluid!

1. Get a big syringe, ideally something with more than 60ml and suck up some brake fluid, dont fuck this bit up. Make sure there is no air bubbles!

2. Connect suitable length tube and pump syringe until fluid appears = this removes the air sitting in the tube.

3. take off master cylinder cap.

4. Connect to the nipple on caliper, undo first!

5. Pump it in slowly until the fluid starts appearing in the master cylinder resvoir, take this up to the half way mark.

6. While maintaing pumping action on the syringe, cllose the nipple.

7. pump the lever until resistance is felt.

Repeat steps if necessary.

Once firm resistance is felt, bleed the usual way, ie pump hard, hold it in, undo nipple, close nipple and let the brake lever out.

Repeat this until no air bubbles.

Then after get a bungee tie/cable and tie the lever down and lever over night = this removes any remaining air bubbles out of the system.

Oh and replace master cylinder cap.