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Rear brake bleed dramas!!!!!!

3K views 4 replies 3 participants last post by  criticalmass181 
#1 ·
Hi Guys and Girls.

I'm after a bit of input, as to my present woe. I've almost finished rebuilding the once wreck of a '99 R1, and i'm having all manner of problems bleeding the rear brake. I've installed HEL braided stainless brake lines, front and rear, to standard callipers (with Brembo pads). I also have Goodridge hydraulic brake switches, aswell. I've replaced the guts of the rear Master Cylinder with a genuine Yamaha OEM kit, and I STILL can't get the brakes to firm up. The crush seals have crushed....the parts are new.....and my patience is wearing thin, to say the least. The only thing I can think of, is that there's a HUGE air lock somewhere, and I can't make it move. I've vacuumed the lines, tried good ol' fashioned pump and release, and prayed to the brake Gods (Just in case...) I've bled many brake systems on bikes and cars, and have never come across this kind of frustration before. Any ideas? Any input is good input. Thanks in advance.
 
#2 ·
I usually have to extend the line with the rear wheel disconnected while still having the caliper mounted right side up.

It's really hard to bleed an extend rear brake line for an under slung caliper.

When pumping the lever, push it really hard and faster to force the air out. Release the lever in a normal manner.

Hope this helps.
 
#3 ·
Thanks One2. I was kinda hoping that there was an easier way, than to remove the back wheel.....but I guess i'll just have to bite the bullet. If you're going to build a design fault into a bike, you should, at least, make a way around it. I don't know if you're familiar with the old ZXRs, but they had an extended rear brake line that went all the way around the back of the swingarm, so you could remove the calliper without removing the rear wheel. In any case, thanks for your help. Take care.
 
#4 ·
Tilt the rear caliper so that the bleed nipple is the highest point. Then pump several times, and while the lever is depressed, open the bleed screws and kee the lever fully depressed. When fluid stops coming out, tighten the screws. Repeat several times.
 
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