Bleeding brakes - how?

So the rubber boot in my rear brake reservoir completely destroyed itself some how. (don't ask me how, it just did) Well I bought a whole new/used master cylinder and reservoir. Installed it and it seems like there's air trapped in the line, I bleed the lines but the pedal is still soft and will not stop the bike. So my question is, has anyone ever had this problem? and/or is there a better way to bleed the brakes?

first how did you bleed the brake before was it with on of those carp kits or did you do it "normally"

I did it the normal way, and I thought I had all the air out but its still soft an won't stop the bike. :-/

check the seals on the res , do you know the fairy liquid trick
double check your fitting of the hoses, and tbh id have the brake off and service it while i was messing about anyway

[yorkie_chris]

Bleed it out of banjo behind MC.

Air bubble gets in there and will not move because it is highest point in system... look at it and you will see

[Paul the 6th]

I've also found that attaching a bit of clear hose to the bleed nipple on the calipers allows you to see air bubbles coming out in the brake fluid so you've got more chance to work out when the lever should be starting to stiffen up, rather than guessing whether any bubbles are trickling out in fluid

Ok! Thanks Guys I'll try these suggestions as soon as I can.

I rebuilt my Curvys rear caliper this weekend ready for the winter. Bleeding the back brake is easy if you know what your doing and should take no more than 15 minutes or so. There are a couple of little tricks though (as already pointed out above). I've got no experience of speed bleed valves or bleeding kits - all I use is a bit of plastic tubing and a big syringe - the following method works well for me when starting with an empty system (i.e. after a rebuild/changing brake lines e.t.c.) - YMMV of course:

- Put caliper on bike
- Open both bleed nipples and put a bit of empty plastic tubing on the front (exhaust side) nipple
- Get a syringe full of new brake fluid and connect it to the calipers rear bleed nipple via some tubing
- Push the brake fluid into the caliper with the syringe- when fluid starts to come out of the front bleed nipple tighten it to close it (I do this to try and minimise air getting trapped above the banjo at the front of the caliper)
- Keep pushing fluid in via the syringe/rear bleed nipple until you see it filling the reservoir under the rear seat
-Stop pumping when the reservoir is fairly full then close the rear bleed nipple and remove the syringe
- Pump on the brake lever a few times
- Tap all hoses/MC/caliper lightly with a spanner to get any air floating upwards
- Try and tip the bike towards me a bit so the banjo at the back of the MC is the highest point in the system (another set of hands helps here), apply a little pressure to the brake lever then crack open the banjo at the MC until a little fluid runs out and close it again before releasing pressure on the brake lever
- Repeat the above step for the banjo on the caliper itself (although I'm not sure it air can feasibly get trapped behind this but I like to be thorough)
- Repeat the above step for each of the bleed nipples on the caliper until fluid with no bubbles come out (usually only takes 1-2 attempts)
- Pump on brake lever until the pads are pushed into contact with the discs periodically checking the reservoir and topping up as needed
- Screw top on reservoir/remove all hoses/torque bolts e.t.c.

This gives a good firm brake lever and reasonable brake stopping power. After a first short ride I bleed both the banjos and nipples again to remove any air still in the system which has floated up. The rear brake is then good enough to lock the rear wheel if required.