Brake Bleeding?

[Wabby]

I'll make the introduction to this issue quick.

My brakes were garbage so I wanted to make them better! (I mean I could pull them into the bar and keep going)

I ordered some braided lines, and a Master Cylinder rebuild kit (calipers are perfect)

Fitted the lines, rebuilt the M/C - Now it comes to bleeding...

I can get pressure in the system, but I can STILL pull it back to the bar (If I try hard enough). It 'bites' about 1 inch from the bar.

I have bled until their is no bubbles in the fluid, and have also bled the M/C (This made them better, but still by no means good)

I'm pretty sure their is a lock of air somewhere in this fucking system, but how do I get it out?

ITS DRIVING ME UP THE WALL!

Please help
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What restriction?

[nowhere.elysium]

I was told yesterday by an ex-courier mate of mine, that an easy fix for airlock is to tie the lever as close to the bar as possible, and leave it overnight. I've not tried this, so I can't vouch for it, but it may do the trick.
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[lonner]

hi mate

dont know your bike but try this

bike on side stand and bars full left lock.

then move leaver about 5mm a few times (this removes air trapped in the MC)

then if its still a little soft zip tie the leaver for the knight and try again in the morning.

also undo bleed nipple half turn then pull leaver to bar and hold then re-tighten nipple then release leaver.

that should shift the air if any is present in the calipers

hth

[andys675]

did you push the pistons back in before you started?

[Wabby]

[Ichy]

Tie the lever to the bar overnight.

While its tied up give the brake components a tap with a bit of wood or something soft to help dislodge any trapped air.

[Noxious89123]

[lonner]

noxiouse wrote


Oepning the bleed nipple before you apply pressure to the system means that air can get in as easily as the fluid can get out... If you pressurise it by pulling the lever, *then* open the nipple, fluid will be forced out, and air can't get in.[/quote]


really

you don't know what your talking about young man.

air is drawn in when the leaver is released .

so until you actually learn how to do brakes and understan them you should not comment.

ps pushing the pistons back in makes no difference to bleeding.

you get the air out by using the correct technique end of

[FerretFing]

I can thoroughly recommend one of these;

https://www.ccw-tools.com/product.asp?P_ID=12360&af=1792

you could probably find it cheaper elsewhere.

it takes a lot of hassle out of it! Just sucks through the fluid slowly with no chance of any air getting in if you do it correctly, no pumping needed.

Also, I`ve heard several mechanics say that leaving it tied up overnight puts unnecessary pressure on the seals I have to say it`s worked for me in the past though.

[sickpup]

[Wabby]

OK.

So I removed the calipers from the forks, and lifted them ABOVE the master cylinder.

Bled and almost immediately got some RIGHT pressure on. I mean as soon as touched, they were SOLID.

Put them back down to forks, forced pads back (was together), and re-fitted to forks.

Pumped back up to get pads to discs - Back to only biting one inch from bar.

Any ideas?

Their is a possibility air got sucked in just before putting them back down to the forks - As the fluid was quiet close to the hole to M/C level.

ARGH!
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What restriction?

[Noxious89123]

[lonner]

noxiouse wrote


Really?

I'd have thought if you open the nipple without any pressure in the lines, then you could end up with a little bit of air getting in...

That's why people always say about attaching a piece of clear plastic tubing to the nipple, and submerging the end of it in brakefluid....[/quote]


hi
sorry that was not meant to sound like a bollocking

that's so you can see the bubbles and save getting fluid on the painted surfaces.

the pipe submerged in fluid stops air being drawn back when you realese the leaver.

if you think logically the brake system is gravity fed (res is higher than the caliper)so the fluid will come out of the nipple and not the other way

bleeding brakes is very simple but its amazing how difficult people seem to make it.
the main problem i think is they try to do it quickly and that's what gets the system full of air.

hth

[chris-red]

I'm doing mine too and having trouble. I can;t get any fluid through the system. It is completely emtpy atm and with fresh fluid in the reservior I'm squeezing the lever but it will not go through the system.

I'm gona try Sickpups filling the caliper up when I have another go.
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[cammy mack]

hi

this may be off no help whatsoever but my back brake has the same problem. my solution was to push the pistons right in and put 2 wood wedges between the disc and the pads.

i bled it as normal till the pedal was solid then slowly removed the wedges. back brake is now solid.
job done

[Ichy]

[Wabby]

[johnnyfaro]

I had a lot of problems with my brakes recently, turned out that when they had seized (which is why i stripped and rebuilt the calipers) had warped the discs so that when the brake was applied it just bent the disc back rather then gripping on it.

[Ichy]

Haven't tried the hand pumps, mine works off my compressor. I Find it great for filling the system but I still prefer pressurising the old fashion way.

A great big syringe to suck the fluid through would probably work just as well.

[el_oso]

i've used the syringe method.
metre or so of b&q clear plastic tubing and a plastic syringe. worked every single time. can completely re bled the entire line in about 5minutes.
also only costs a few quid at the most.
also twisting and bending the brake line helps get rid of this air
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[lonner]

[Wabby]

Where to buy a suitable syringe from?
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What restriction?

[lonner]

[Ichy]

https://cgi.ebay.co.uk/Syringe-50ml-New-Sealed-NO-NEEDLE-art-cake-deco-etc_W0QQitemZ290348556603QQcmdZViewItemQQptZUK_HomeGarden_Garden_PlantsSeedsBulbs_JN?hash=item439a1f613b&_trksid=p3286.c0.m14

Just search for '100ml syringe' if you want it bigger, costs about £4.