Bleeding brake on R90/6

Never did this. Need a walk thru or a video of how.

Get one of these.
I got mine at Harbor Freight

also get some small hose clamps

http://www.youtube.com/watch?v=PwAQ2qDQjPg

I have used the Mityvac but I prefer to use the bleeder bags and just manually pump the lever-- http://www.speedbleeder.zoovy.com/product/BAGANDHOSECOMBO/Bag-Hose-Combo.html

The hose fits securely on the bleeder and solves what used to be the biggest problem for me. I'm not sure it's worth a video -- attach a bleeder bag, loosen the bleeder just a tad so it is a bit more than finger tight, then squeeze the lever, loosen the bleeder until fluid flows, close the bleeder, release the brake lever. Repeat until the brake fluid in the tube changes color. You need a bit of stretching to get the left front caliper done but I'm old and not very bendy and I can still manage it. And continually check to make sure there is enough fluid in the reservoir. If you want to be overly cautious, or if the fluid is very old, get an ear syringe and remove the old fluid from the reservoir and fill it with fresh fluid too avoid contaminating the new with the old.

I also installed the "speed bleeder" fittings on each caliper when I put on SS Speigler Brakelines

http://www.spieglerusa.com/brakes/speed-bleeder.html

It's like bleeding most any other brake system. Here's what I've done:

- remove tank to expose master cylinder. Remove cap to master cylinder and cover the opening with a rag or paper towel...this will prevent the "squirts" from going all over.
- find a suitable diameter clear rubber hose that fits over the nipple/bleeder valve on the front caliper. Run that hose to a container below the caliper outlet.
- use a flare (or line) wrench that fits the nipple flats...probably 10mm. A flare wrench is a 6-point box wrench with one side open so that it fits around the a line or in this case the hose.
- carefully crack open the nipple just to loosen it up, then retighten slightly
- find something that you can tape/wedge between the hand lever and the handlebar grip. The purpose is to restrict the movement of the lever to essentially the same travel as you normally see during braking. The idea here is to not let the internal piston on the master cylinder exceed the normal range...if it does, the piston o-rings will be in "uncharted" territory where there could be rust or other corrosion, which could then tear the O-rings.

Now comes the bleeding part.

- pump the lever a few times to build pressure. On the last pump, hold the lever against your handlebar wedge.
- reach down and loosen the nipple. Watch the fluid as it comes out...blackish, bubbly, etc. The pressure on the level will go away but don't let up on it.
- tighten the nipple to close off flow.
- repeat this process of pumping the lever, holding it, cracking the nipple open letting fluid out, close the nipple

From time to time, recheck the master cylinder. At no time do you want the fluid to drop too low in the reservoir...that will let air into the line and your bleeding gets more complicated. When necessary, add clean fluid (DOT 3/4...I believe 5.1 can be used but not 5.0. 3/4 is readily available so use that). Continue to watch the fluid as it exits the bleed nipple. When you begin to see clean fluid come out the valve and no bubbles, you're done. Suggest that you find a rope and pump the lever once last time and tie it off overnight. Then recheck by pumping and bleeding a few more times. Finally, top off the reservoir.

That's how I would bleed your front caliper. HTH.

Kurt really covered the HOW's to do it manually. Am sure some folks will chime in on how to use one of the pump gizmos. The biggest thing is to do this little chore EVERY year. Brake fluid atracts moisture through that little breather hole in the cap and that moisture attacks the piston/sleeve of the master cylinder making little "bumps". Then when you pull/push the piston across those the seals/rings on that piston get torn and allows the master cylinder to leak or causes it to "bind" up. Then you end up with brake fluid all over your electrics there on the /5 and /6 or your lever not working properly..............God bless.......Dennis

Thanks all

Sounds like I may be able to do this. A speed bleeder might make it easier but doable without as well. I wonder what size hose fits the nipple? Flare wrench? Don't have one. Have to look into that.

You can probably get by with one of the open end wrenches in your tool kit or any regular metric wrench. Open end wrenches, especially the cheap ones, can spread farther open when you use them on very stuck nuts/bolts. They can then round the nut/bolt. A box wrench is best. A flare wrench is something in between, being a bit stiffer and less likely to widen when working on something.

Just a plain ol 10mm works well. Have used 1/4" inside diameter, both the gray fuel line stuff and clear. For me, I use a box 10mm, put it on the bleeder valve, and then put the hose on with a clamp on that. I like to bleed the old stuff into a jar so that I can see what is coming out. I forget if one keeps the end of the hose in the jar covered with fluid it aids in not pulling back any air when you open and close the valve with the wrench. Perhaps someone can talk about that????...........God bless........Dennis

DennisDarrow said:

I forget if one keeps the end of the hose in the jar covered with fluid it aids in not pulling back any air when you open and close the valve with the wrench.

Click to expand...

Technically, I think you should have the downstream end of the hose dunked into a little bit of the fluid. But what I usually do is watch the fluid that comes out of the valve and be sure that I close the valve before I release the hand lever. That way, no fluid (or air) is drawn back in. So, just taking your time and watching what's going on should be no problem.

Yesterday I read Snowbum's article on brakes top to bottom. lots of info.

http://bmwmotorcycletech.info/brakes.htm

Cheers