Brake bleeding problems.
 

my front brake lever just wont firm up!!;)
I've searched the threads and I know there are plenty, and i've tried all the ideas in most of them but to no avail.

I'd taken my calipers off to give them a good clean up, then after popping one piston right out and not managing to move the others, I tried to fill the system up again and bleed it to use the system itself to remove the calipers.
I could get no pressure in the lever at all, despite trying to bleed for ages.

I then decided to get a second set of calipers given the state of my old ones, and the ones I received were in much better condition so I put these one.
I've now got the same problem, regardless of everything I do I get no pressure at all.:mad:

I've, injected fluid directly into the caliper, bled normally, i've bought one of those Motrax 'Little Bleeders' and tied the lever back overnight, but nothing has made any difference whatsoever.
The pressure in the system was fine before I started messing, so I cant think the master cylinder etc has gone, so i've just no idea at all.

Any ideas, before it get taken to garage, and I get my pants pulled down?

Many thanks

Daz

Re: Brake bleeding problems.
 

It's very possible that there's an air bubble at the upper banjo on the master cylinder. Gently loosen the banjo on the master cylinder, not enough for any fluid to escape but just enough that you can rotate it, arrange it so it's pointing upwards and the calipers are above it and re-bleed. Clearly you may need to remove the whole system to do this, or remove the master cylinder, pass it down through the fairing and perform the bleeding with it at ground level.

Re: Brake bleeding problems.
 

When I fitted new calipers, I TOTALLY ignored the bleeders!
As long as there is no upwards loop of the line, air cannot collect there. So . .
Fill reservoir. Leave lid off ( it should only be a couple of minutes )
' rattle ' the lever backwards & forwards & watch bubbles come up where the fluid goes down into m/cyl. Easier on nakeds I know but principle SHOULD be same. Tapping the lines may also help although I didn't need to do this.
When bubbles stop you can start bleeding the bleeders 'cos you SHOULD have a bit of feel in the lever. Until this point 'tis a waste of time.
This worked very quickly for me but is a little bit unconventional, so the usual caveats apply.
Best of luck!

Re: Brake bleeding problems.
 

I did mine the other day after accidently popping a piston out while cleaning the calipers.

I had to pump the lever for AGES before fluid even began to come out the bleed pipe.

Then had to swap between bleeding each caliper about 3 to 4 times, it wasn't until there was quite literally not even the slightest bit of air bubble in the tube before I got pressure back, and you had to be quick with locking the bleed nipple back up and topping the resovoir back up frequently while pumping... it was very easy to get an air bubble back into the system by not watching the fluid level.

Never done it before so did not know what to expect.

Was easy enough in the end... just patience, the brake system is so simple I never realised.

Re: Brake bleeding problems.
 

I've done this method too. But only when the conventional method failed me. A trapped air bubble refusing to go down the system sometimes comes up much easier.

Re: Brake bleeding problems.
 

You could always try pulling the lever tight and cable ties it over night, the pressure is supposed to help drive out air bubbles and get the lever firm again.

Re: Brake bleeding problems.
 

This worked for me to an extent with the cap off the top of the res (but put a cloth over it fixed by rubber band. I then attached a tube over the bleed nipple and blew until I heard the air bubble come out of the res. I left it like this over night and The next morning it made it firm enough that I could pump the fluid round so I sucked until the brake fluid came through into the tube. Finger over the end of the tube to hold the fluid up and then tigthen off the bleed nipple.
They were spot on after that.

Re: Brake bleeding problems.
 

Cheers Guys.
I'd tried all of those methods apart from turning the system 'upside down' or blowing/sucking from the bleed nipples.

I'll give these a go tonight, and see how I get on.

Its really frustrating and although it takes patience, the complete lack of pressure at the lever is starting to bother me, in terms of thinking something has 'broken' coincidentally whilst changing the calipers.

I'll let you know how I get on.

thanks again.

Daz

Re: Brake bleeding problems.
 

My knees are trembling :-)

On a serious note, this can be really easy if you approach it in the correct way. What I find works for me on a empty system is to link everything together, pop a clear tube onto one of the bleed nipples and open it, leave it open and then fill the res at the top.

You can help it along by gentle moving of the brake lever and squeezing the rubber tube between master cylinder and res (on a faired model). Other than that just keep an eye on the fluid level and wait for it to drip from the tube at the bottom. When it does, move the tube to the other caliper and do the same.

At that stage its back to simple brake bleed technique to remove any trapped air. Works every time for me on an empty brake system. Should take you 15 mins in total if you include drinking a cup of tea.

Re: Brake bleeding problems.
 

when i realese pipes or hoses or calipers at work on car i put a rod on the seat to the pedal putin as much pressure on the peddal as possible and then IT STOPS FLUID LEAKING OUT ..SO IT STOPS YOU LOSING ALL your very expensive FLUID IN THE SYSTEM AND YOU DONT GET ALOT OF AIR IN THE SYSTEM ... very good trick my old boss tought me lol i was just wondering will it work on a bike ,....