Brakes, air and the end of the line...

So I reassembled my bike. It now has new rear brakes, rebuilt MC, new brake lines, rebuilt caliper, rebuilt forks, rebuilt carburators...

BUT! I can't get the brakes to work again... I have a fully functional bike... that can't stop

It seems I might have some air that keeps getting stock in the system. Any trick on getting it out? There's simply no pressure getting to the caliper. Plenty of fluid makes it to the bleeder valve though...

I have one of those one way only tubes from chacal that I fit on the bleeder valve, it basically does the same thing as the Hayne's manual recommend in preventing air from getting back in. It'll fill up with fluid, leave one bubble in there that I can't get rid of and that's about it. Should I just keep on pumping? I just feel like it's all going straight into the pan :S.

Thanks ahead!

 

Slight update!

So I closed the top of the MC and just started pumping it that way over and over again. Now it brakes. Is that it then? I just had to pump it quite a bit?

 

The one way valves are OK if the bleed nipple itself isn't allowing air to draw past the threads when you released the lever. To be honest I prefer to bleed brakes "manually" opening and closing the bleeder. It's a bit of a chore on my bike with antidive & 4 bleeders but does the job & you *know* nothing's drawing back in.

Saying that, sounds like you may have had a trapped bubble in the M/C or splitter that's worked it's way out now.

Just a point as you've pumped the lever with the cap on, quickly just remove the cap again & ensure the rubber gasket's bellows (the part of it that deforms to allow fluid to drop as pads wear, while keeping the fluid sealed in the reservoir) is retracted again. I find it can slowly draw the pistons back and leave you with no brakes for the first use of the day if it's left "sucked" into the reservoir at all.

If the lever feels good then you've probably got it, but if it's still spongy possibly needs a bit more bleeding.

 

Thanks a lot! I'll try manually next time.

 

Back on the drawing board!

Could air in the line cause the piston not to retract enough? The brakes are now rubbing against the disc...

 

Rubbing against the disc that prevent the bike from moving? Or rubbing, like, barely touching and not retracting, but the bike is still easy to push around the garage? Because the latter is how the brakes actually work, the pad will still "appear" to touch the disc, but when you push it around the garage, you KNOW it's not touching (if you've ever had a stuck pad).

Also, when you cleaned the master cylinder, was the little return port was clean properly? The little hole that looks like it wasn't quite drilled all the way through? It's referenced in most master cylinder How-to's on this site.

Finally, once you've finished bleeding, you need to re-bleed after your first ride. Air bubbles can be dissolved in the brake fluid, such that it is super-saturated, and the vibration from a ride will bring those bubbles out of solution. Those bubbles will then make their way to the bleed screw. Don't worry, it'll just be one little bubble per bleed screw, you won't go through the same bleed procedure that you did when you first filled the system (as long as you don't introduce air into the system when you bleed)

 

Yeah the pads are just rubbing as you said, so I guess I'm fine!

After your comment I went ahead and tried my bike on the street right away . The bike works perfectly! It even started on the first try with me forgetting to put the choke on! After an entire winter!

Thanks to everyone who gave me some help!

 

That doesn't quite seem right.
I need to use choke when it's 35 degrees C out at the start of the day.

 

Depends, some days mine starts fine no choke other days she needs half choke to start.

 

A big +1 there,

also, on a 650 (single line) you can crack the top banjo "just loose" while bleeding, as air can be trapped there. (use a rag !!).

Don't forget to re-bleed after 300 miles.