Bleeding Brakes

[Alive]

I've bled a few brakes before, but always seem to have problems getting air out.

Could someone please let me in on the secret???
How do you get air locks and bubbles out while bleeding brakes?

I have put about 300ml of brake fluid through the front brakes on an XJ550 and still they are soft.

P.S. Master and both slaves have had new kits put in them and do not leak.

Cheers :)

:scooter:

[dhunt]

I've bled a few brakes before, but always seem to have problems getting air out.

Could someone please let me in on the secret???
How do you get air locks and bubbles out while bleeding brakes?

I have put about 300ml of brake fluid through the front brakes on an XJ550 and still they are soft.

P.S. Master and both slaves have had new kits put in them and do not leak.

Cheers :)

:scooter:
Tap any joints with a spanner incase there is air there. Sometimes I also open the banjo bolts while squeesing the brakes to get air out there (You may want to do this is if you have just put in new kits). Other than that I don't no of any secrets.

[idb]

After finishing the bleeding - tie the lever back to the bar with the screw cap off and leave it overnight for any bubbles to rise up the lines.

[Alive]

Banjo bolts???

Are they the ones that screw in to the master and the slaves with two holes half way up them?

[Alive]

After finishing the bleeding - tie the lever back to the bar with the screw cap off and leave it overnight for any bubbles to rise up the lines.


I'll give that a go tonight... cheers :)

[nodrog]

unbolt the calipers and hold them above the master cylinder, before bleeding. or reverse bleed them through the master cylinder.

[Alive]

unbolt the calipers and hold them above the master cylinder, before bleeding. or reverse bleed them through the master cylinder.


Reverse bleed them??? How does that work?

[dhunt]

Banjo bolts???

Are they the ones that screw in to the master and the slaves with two holes half way up them?
Yeah. I find air can get trapped there when I change the master kit.

[Alive]

Yeah. I find air can get trapped there when I change the master kit.


Sweet... I'll have a crack at that ;)

[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.

[T.W.R]

After finishing the bleeding - tie the lever back to the bar with the screw cap off and leave it overnight for any bubbles to rise up the lines.

Not really a good move, brake fluid absorbs moisture quite readily so leaving the reservior open & exposed to dampness or cold night air over night can be enough to contaminate the fluid.

Pressurizing the system properly during bleeding forces most air bubbles & crud out of the system.

[slimjim]

I've bled a few brakes before, but always seem to have problems getting air out.

Could someone please let me in on the secret???
How do you get air locks and bubbles out while bleeding brakes?

I have put about 300ml of brake fluid through the front brakes on an XJ550 and still they are soft.

P.S. Master and both slaves have had new kits put in them and do not leak.

Cheers :)

:scooter:

mate go to any car shop and buy a self bleeding kit ,, its bloody cheep as , and only you need to use it,, dont need two poeple is what i mean,to bleed the system does it for you

[Alive]

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.


Good stuff..... It did take a while to start pumping fluid out in the first place. I left the hose off until it had a good stream of fliud coming out of the master, then tightened the banjo bolt and started bleeding.

[Alive]

mate go to any car shop and buy a self bleeding kit ,, its bloody cheep as , and only you need to use it,, dont need two poeple is what i mean,to bleed the system does it for you


I'll go have a look in supercheap ;) Cheers

[imdying]

Yeah, if there's air in the master, you can pump all you want :) One of those self bleeding kits might help, although nothing beats correct technique (I've bled heeeaps of bikes, never used anything but a hose off of the nipple).

[Alive]

Yeah, if there's air in the master, you can pump all you want :) One of those self bleeding kits might help, although nothing beats correct technique (I've bled heeeaps of bikes, never used anything but a hose off of the nipple).


I will do what you suggested.... then use a self bleeder to get rid of anything in the lines.

Thanks for your advice... appreciated :)

[imdying]

Yep, you'll need a hose and bottle anyway, and the self bleeders are cheap as chips, so you might as well have one!! Generally you can knock them over and not spill anything, unlike the trusty hose and bottle method.... :lol:

[The Pastor]

Not really a good move, brake fluid absorbs moisture quite readily so leaving the reservior open & exposed to dampness or cold night air over night can be enough to contaminate the fluid.

Pressurizing the system properly during bleeding forces most air bubbles & crud out of the system.

Arrr... you do put the lid back on the resivar after tieing it up, Its the best way (imo) and works great.

[idb]

Not really a good move, brake fluid absorbs moisture quite readily so leaving the reservior open & exposed to dampness or cold night air over night can be enough to contaminate the fluid.

Pressurizing the system properly during bleeding forces most air bubbles & crud out of the system.
True enough I suppose, but it always works for me nevertheless.

[imdying]

But if you bled it properly, there would be not waiting over night, you could just ride it straight away!

[The Pastor]

But if you bled it properly, there would be not waiting over night, you could just ride it straight away!


True, Or you could just bleed the brakes at night just before bed - only takes 15mins.....

[FROSTY]

guys has noone picked up on what the bike is--An XJ550
Dude if the bike still has the factory fitted brake lines you will NOT get a firm lever. The brake lines are just too old. -They are literally bulging as you apply the brakes
at this point most folk will be standing up saying "Braided lines" --nahh stuff that. Just get some factory lines from a (much) later bike.
doesnt need to be a yam. as long as the fittings at each end are the same and the lines are the same lenth.
Ill betcha $100 youll get a heap better lever

[Korea]

I've had really good results by not pumping the lever all the way to the stop/handlebar. Just pump a few times, then squeeze just a little (about 2-3mm); seems to make a whole heap of bubbles rise up.
Good luck with that...

[imdying]

True, Or you could just bleed the brakes at night just before bed - only takes 15mins.....I'm assuming to let them stand overnight? You could have them bled properly in 15 minutes anyway!?!

[Ghost Lemur]

Came across this (http://www.motiveproducts.com/02bleeders.html) a while ago.

Thoughts? I'm sure the universal one could be modded to work on bikes.

[dhunt]

Came across this (http://www.motiveproducts.com/02bleeders.html) a while ago.

Thoughts? I'm sure the universal one could be modded to work on bikes.
hmm a bit dearer than my $2 of hose and peanut butter jar. It's very universal - works on cars and bikes. :done:

[Warr]

Mr "Alive"
Bleeding brakes on front of bikes is difficult for sure.
By design the slave cylinders are lower than the master... well mine are and since air rises we have a problem....

Although my XJ900 had original lines on it I could get them pretty good... BUT I had to reverse bleed them. No-one on here previous has mentioned my method of doing this so for your info my un-patented method.
Find a friend who works in a medical place and get a reasonable size syringe and tube large enough to go over the bleed nipple and snug on the syringe.
Remove the master reservoir cap.
Fill the syringe and tube up with fluid and put onto the bleed nipple furtherest from the master cylinder and push the fluid through. When it runs clear lock off that bleed nipple and work on the next.

And when you are all finished wash out the syringe and put some vaseline on the rubber so that it will still work for next time.

[The Pastor]

I'm assuming to let them stand overnight? You could have them bled properly in 15 minutes anyway!?!

Yeah, that was my point - but it doesnt hurt to leave them over night anyways.

[RiderInBlack]

This is the method I use:

This the same as I do for brake bleeding (from this old thread "Bleeding Hydraulic Clutch (http://www.kiwibiker.co.nz/forums/showthread.php?t=9581&highlight=Clutch)":

Quote:
<TABLE cellSpacing=0 cellPadding=4 width="100%" border=0><TBODY><TR><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by RiderInBlack
"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):doh: 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:niceone:
</TD></TR></TBODY></TABLE>
Hope it helps.

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as I posted here http://www.kiwibiker.co.nz/forums/showpost.php?p=233435&postcount=5

[imdying]

I can't think of a worse idea than recycling the fluid (and all the crap that ends up in the slave (clutch slave/calipers/whatevers at the bottom). Brake fluid is cheap, and if your technique is tight, you'll only need a 500ml bottle.

Assuming your pumping fluid and not air, just keep pumping the lever till clear fluid comes out the bottom. Then resort to your close bleeder, pump pump pump, hold lever in, open then close the bleeder, repeat x3-4 technique. And that's it, you're done.

If that brings no joy, you've either not clamped your lines off when you've had your calipers off, and the masters run dry, or you've managed to make the master run dry by some other means... either way, dry master == no pumping. That's because she simply won't pump air. If you're in that situation, undo the hose at the top, prime the master (instructions in this thread), then bled as described above.

Using that technique you'll get anything to bleed, pretty much no matter how poked and expanding the hoses are. Sure the flex might mean that lever will feel crap, but the bleeding will be fine :)

[The Pastor]

Also to note, If you have more than one bleed nipple (i have/had 6!), you will have to repeat the process for all of them. I used less than 200mL for my brakes - Is that abnormally low??

[RiderInBlack]

There is no crap because I replace all the old shit first before using the "recycling method". I developed this method due to a bike shop mec having not bleed the brakes well enough. Found there was tiny wee bubbles still in the line causing my brakes ta be "soft". These wee bubbles took a lot of bleeding and fluid ta remove, but once removed my brakes worked perfectly with no further problems. So now I go the extra distance when bleeding my brakes ta make absolutely sure there is no trapped air still in the line.