Brake Bleeding

[Anonymous]

I installed braided brake lines and new caliper seals on my '83 GS 1100E and then spent lots of time and a full bottle of fluid trying to bleed the system. I have done the bleeding operation previously after a fluid change and had good results even with the anti-dive units still in place . This time I can't get any resistance at the lever at all. There is no more air coming out when I open the bleed valves and fluid is moving through the system but there is just no braking at all. I can only assume that the master cylinder now needs a rebuild. Anyone have any ideas?
Oh yes, I did follow the correct bleeding sequence. How much fluid would you expect to go through to get proper bleeding?

[rodcwer]

it is possible the piston in the master cylinder may not be releasing.I would try to brake open the line at the master and see if your getting flow when you engage brake.let me know what you find

[feelergaugephil]

Lines

Ok, I had the same problem when I put one braided lines on my GS1000.
A little fluid came out and air but it would never pump up, even after bleeding it for over 2 hours, The back was the same.......
Here's the trick....... You have to use a vacuum bleeder, thats the ONLY WAY you will get the system to bleed.
Trust me, I borrowed a friends vacuum bleeder and within 5 minutes I had done both front and back.
It's very easy to use and you'll be astounded how well it does it.

[Anonymous]

I tried vacuum bleeding using a big syringe. I can see how this is the way to go but it just pulls air around the bleeder threads or past the tubing on the bleed nipple. I tried putting grease around the threads with out much success but I guess I'll have another go at it. I don't really want to get into a master cylinder rebuild( it was fine till I drained the system) till I have exhausted all other possibilities. Thanks for the advice. I let you know how it goes.

[Pete Logan]

If your m/c was fine before I can't see why it would go belly up right now.

Pete

[Jethro]

The vaccum bleeder I use attaches to the bleeder valve on the caliper itself. It sucks the fluid and air right out through the caliper. It worked like a charm, but only after I primed the lines. I took the lines right off the banjos and poured fliud through them from the master, then quickly attached the banjos. I used a strap around the brake lever, keeping the master cyl open the whole time.

[feelergaugephil]

There you go, thats the way I tried to explain it to Don.

[Mr. Jiggles]

So far I've done this twice - for the front and back. Both times I used a 60ml syringe that I filled with brake fluid and connected to the bleed screws at the calipers using a plastic hose. I disconnected the banjo bolt at the MC and pumped a couple of syringe's worth of brake fluid through the system. For the front system I had to do this at both calipers. Once this was done I reconnected the MC banjo and used the MC to bleed at the MC and down at the calipers. Each time I had positive pressure at the lever from the start and only saw a couple of minute bubbles during the bleeding process.

Sometimes air will enter the MC preventing it from priming. You might want to disconnect the MC banjo and hold your thumb over the MC opening while pumping the lever until you feel fluid pumping out.

[Anonymous]

Hey, thanks for all the help guys. Problem is I just can't believe that with all the fluid I have run through the system and not seeing any bubbles (got my vacuum bleed syringe to work OK) that I still don't have some other problem...there is still zero resistance at the lever. So, I pulled the MC apart and of course it looks like new in there except for the little holes in the piston being mostly plugged. Anyway, I'm going to rebuild the MC and try that priming of the system idea with the syringe. Won't know for a few days till I get my parts from Bike Bandit. Thanks again for the response.

[feelergaugephil]

Rather than using a syringe, go borrow/buy a vacuum tool thats for bleeding brakes, it will make life sooooooo much easier.

[Jethro]

So, I pulled the MC apart and of course it looks like new in there except for the little holes in the piston being mostly plugged.

Oh dude, there is your problem, I would bet my bike on it. Those holes are the return holes for the fluid, the little tiny one being the most important. Make sure it's clear and I'll bet your brakes work fine.