brake bleeding woes

[XX]

so i'm mr cool mechanic, got my teflon tape, my mityvac, my bought today 8mm wrench, fully ashamed my bike hasn't had its brake fluid replaced in 27k miles, i set off to do both front and back and the clutch.

4 hours later :oops: at least i got done with the fronts.... well, done enough that the brakes work on a hard braking test ride, no leaks to be found yet.

here's my dilemna: the manuel calls for 4 bleed points for the rear brake master, in this order 1) front right center, front left center, back center, back rear. (actually the haynes manual and the honda manual differ on the last 2 but that's not where my issues lay.

i followed the directions, i swear, even got my brother in law involved, doing the pump the pedal then push thingy... valves 2,3 and 4 fluid was solid, got all bubble out.

for the life of me, i couldn't get the bubbles out of the front right valve. UNLESS i did it the poor mans way, hose from bleed valve to bucket of brake fluid below.

oh yeh, once i got all the brake fluid out, before i started all this bleeding, i even went around and teflon taped all the valves too :shock:

i kept going thru brake fluid until i couldn't stand it anymore :cry:

the only thing i could imagine is that because the mityvac was using vacuum pressure, maybe that particular bleed valve needed more teflon tape for a tighter seal, and the air i was getting was from the bleed valve threads. i'm guessing that, that first line since being pretty long, prolly is harder to bleed?

any beginner bleeders out there have similiar situations?

[Redbird]

once i got all the brake fluid out, before i started all this bleeding

Just so I'm clear on this- did you drain the whole system entirely of brake fluid?

If you could be a little clearer about "couldn't get the bubbles out". Is there no bubbles leaving the bleeder, or do they just keep coming? How's the pedal feel?

[XX]

sorry, put more emotions than facts :shock:

i did drain the whole system (rear) by actively pumping out the old brake fluid.

the bubbles i mentioned where as i was at station 1, front right brake bleeder as these steps 1) attach hose, pump up mityvac 2) pump rear brake pedal 2-3 times, then keep pressure on it 3) release bleed screw (brake pedal would depress)... then fluid would flow, and air bubbles, about 3/4 air bubbles and 1/4 fluid.... and i'd just drain the resevoir this way... then i'd stop, refill it (i never let it get below the lower mark)... then i'd try again.. and the same thing would happen.

the bubbles just kept coming.

the brake pedal is firm once again.

and the brakes have been tested and work good, at least the same as they did before i replaced the fluid.

at first i may have been loosening the bleed screw too much.

and at first i may have been pumping up the mityvac too much.

i just don't get this vacuum stuff... but hell, i'm going to try again next weekend! :grin:

[Redbird]

If everthing's all firm as far as the lever and pedal, you may have just been getting some air sucked into the hose from around where the clear vacuum line attached to the bleed valve. Were they real fine (small) bubbles?

I've always found it easier to leave the system full of fluid, attach the vacuum pump and suck out the old stuff while topping off the resevoir with new, never letting any air into the system in the first place. Just keep pulling the old crap out until it runs clear and new. Little late for that tip now, I realize, but maybe next time it'll help.

[mikeG]

Yeah, that's what I do too. I don't obsess over getting bubbles out of teh Mityvac. After doing the mityvac, just do a couple of squeeze hold cycles to make sure there are no bubbles. If the levers are firm, you are probably OK.

MikeG

[Northman]

Take the bike for a quick ride, applying the brakes frequently, then pressure bleed the system once again, just to be sure all air has been removed.

The Mityvac is good for replacing the fluid, but not bleeding, IMHO. Should always pressure bleed to be sure.