Brake bleeding

[Darth_1100S]

Anyone any good ideas for bleeding brakes? I've been pumping away for hours now on the lads brakes - no joy. I've put new braided lines in and I'm having difficulty getting the fluid to flow. I've done what I usually do which is use a syring filled with fluid and back filled it from the bleed nipple 'til fluid comes thro to the reservior. It usually works a treat but not this time!

Dave.

[bigblackfalco]

I usually undo slightly every joint between the master cylinder and the caliper.When fluid starts to show from each joint on its journey downwards,tighten the joint and move on to the next.This usually helps to remove the bulk of the air.
Obviously make sure you don't get brake fluid on any painted surfaces.
HTH?
Bailey.

[winger]

Hi Dave

Apologies if i'm teaching grannie to suck eggs!!!,but when you pull the lever in are you locking the bleed nipple off,i've always found the best way is one hand on the lever other on the spanner locking the nipple off,start to pull lever unlock nipple,lever to the bar lock of nipple,bit like patting you head and rubbing your belly!!!,when i've got even remotely like just put elastic band over bar and lever and let it bleed it's self.

To save the mess always had one of those orange bleeder pipes with the valve in the end into a jar.

Chris

[Darth_1100S]

Thanks but tried all that chaps! Just been having another go at it, I'm starting to think the master cylinder may be shagged! Strange, 'coz it was ok before I stripped the bike down. I'm leaving it til tomorrow now - I'm pissed off with it. Maybe I'll get an idea while I'm in bed tonight....no not THAT kind if idea

Cheers - Dave.

[bigblackfalco]

How old is the bike??
Bailey.

[gus]

Dave
Turn the bars to completly to one side,cant remember which now.Air can get trapped in mastercylinder and prove a right git to bleed brakes.Be careful as brake fluid will go everywhere.I bleed my brakes the old way,pump lever then undo nipple,tighten nipple pump up lever and repeat.Finally finish off with an elastic on overnight as chris recommended.
gus

[Darth_1100S]

Bailey the bike is a 94 XJR400.

Gus it's the back brake I'm having probs with, which makes me think the cylinder's goosed. It's only got to pump down about 14". I'll take it off again tomorrow and have look at it. There's no leaks from it tho. It's making a small effort to move the pads but not a lot.

I've not started on the front brakes yet - thta delight awaits for tomorrow as well!

[bigblackfalco]

The age would suggest that it could be the MC at fault.Sometimes if the fluid has never been changed,it becomes full of water moisture which makes the fluid turn a cloudy brown colour.This in turn corrodes the inside of the MC bore.
If it doesn't look too bad,try giving it a rub with a very light 'wet& dry'paper.Sometimes this is enough to give a good seal again(oink,oink)!
HTH?
Bailey.

[Jason M]

Mate - sounds exactly like the problem I had with the Thundercat when I'd just removed and cleaned the pistons.

The solution is to get some mole grips on the brake pipe just where it exits the master cylinder - probably best to put a bit of old rubber hose or someting in the jaes of the mole grips to protect the brake line. Pull the level to get pressure then release the grips a bit and let it flow through - then quickly clamp the pipe again and let the lever back out. Do that repeadidly and it'll come back hard - well mine did anyway. Tip comes courtesy of a Yam mechanic I phoned to buy a new master cylinder cos I though mine was knackered

Good Luck

Jason

[Jason M]

Oh yea - forgot to say, don't have the bleed nipple open when you do this - you might need to bleed the last of the air normally afterwards

[Darth_1100S]

Jason, thanks for the tip I'll give it go later, that's one I've never tried!
In fact thanks to everyone for your help - I'll let you know how I get on later

Cheers - Dave.

[mdouglas]

If you're anywhere near South West London, I've got a MityVac vacuum bleeder you can come round and use. Through pumping of the bleeder, you create a continuous vacuum that sucks fluid down through the system. Eliminates the chance for bubbles in the system to only get so far down only to be sucked back up (which is what the Mole grip tricks achieves). It makes brake bleeding a one man job, even on a car.

I did notice that Draper had added a metal barrelled equivalent to their catalogue for a lot less than the hundred sheets I think I paid for the Mityvac:

http://www.drapertools.com/draper/templ ... M+TEST+KIT

[Darth_1100S]

Thanks for the offer m, but I'm all the way up in Lancashire. I had thought of popping to Halfords, they have something similar. I'm just off to try Jason's idea now I've got a chance.

My lad's just passed his car test his morning so I've just been on the m/way with him. Why they don't include it on the test is beyond me!

Anyway now I've got time to,myself for a bit I'm off to do some bleedin' brakes!

Cheers Dave.

[Darth_1100S]

Wa hey! I've got fluid coming through. I tried Jasons idea then cracked open the first banjo joint on the cylinder and pumped it, a big splurge of air came out that must have been trapped there

Thanks for the help guys

Dave.

[Jason M]

Wa hey! I've got fluid coming through. I tried Jasons idea then cracked open the first banjo joint on the cylinder and pumped it, a big splurge of air came out that must have been trapped there

Thanks for the help guys

Dave.

Excellent news Dave. Now... at £55 + vat an hour...

I love it when something just works!

Good luck with the rest of it

Jason