bleeding brakes

[stephen hall]

any advice please ; I have just fitted new brake and clutch lines [stainless type] the rear brake bleed up aok took a while but its fine ,the clutch the same found it a right git when i first did it a few years ago and found it bleeds half way so i loosen off the slave cyl bolts by a few threads hold the lever in do them up again taking care and he presto it works now the front is proving a right tit no way will it go i pump the lever 3/4 times slack bleed nipple fluid /no bubbles flow then tighten up again still no pressure at the lever . no air or fluid leaks no bubbles coming out only fluid ? where am i going wrong have been at it all afternoon with no result any advice would be much appreciated thanks

[Iconic944ss]

just on way out bud - but search the site on 'bleeding' and also the archive....I'm sure theres aome stuff in here !!

Frank

[Jools]

I've had problems bleeding a back brake. I finally got good results using a pressurised bleed system that I got from Halfords. Can't remember who makes it - I think it's called an eezibleed - but essentially, its a tough polythene bottle with two tubes coming out of it.

One tube comes right down from the bottom of the bottle, through the bottle cap and finishes a couple of feet later in a screw cap that fits in place of your master cylinder cap. The other tube has a valve on the end just like a foot pump, that you clip onto a tyre valve. That tube pressurises the polythene bottle.

So you hook it all up dry, clip the air valve on to your front or rear tyre and make sure there are no leaks. When you're sure that there are no leaks, you fill the bottle with brake fluid and clip the air supply back on. Now, the bottle is pressurised and the fluid is forced through under pressure, so all you need to do is open the bleed nipple until the fluid runs clear.

It's a great way of forcing airlocks out, but if you end up using one make sure you have no leaks - brake fluid fountains are no fun.

I know this is stating the obvious, but I once spent a few hours trying to bleed a front brake with exactly the same symptoms as you describe - then remembered that I had left the diaphragm in the master cylinder reservoir

[Edited on 25-3-2004 by Jools]

[Derek]

The trouble with bleeding both the clutch and front brake is that air usually gets trapped at the master cylinder banjo. The trick is either to loosen the banjo slightly, pull in the lever to eject the air, tighten the banjo then release the lever. This however involves catching the fluid with a rag and is potentially damaging to the paintwork.
Alternatively lean the bike so that the reservoir is higher than the banjo and gently jiggle the lever in and out. The air will return to the reservoir and out of the system, you'll see the bubbles. If you find it easier you can take the master cylinder off the bars to do it.
For the back brake, take the caliper off the bike and hold it so that the nipple is uppermost when you bleed it.

[jock_lock]

Instead of loosening the master cylinder banjos, you could replace the banjos with standard bleed nipples. I did that for the clutch and rear m/cyls - hey presto instant firm levers /pedals.

You can replace the brake m/cyl banjo with a bleed nipple too, but you need an extra long one, and I've lost the URL of the only website I ever saw that sold them!

[stephen hall]

air trapped in top bango bolt ,slight slackening and out she goes all aok now thanks guys cadwell ere we come