I have recently re-built the front and back brakes on my '03 Ninja B1H - master cylinder, goodridge hoses, caliper seals EBC HH pads…the lot!
I’ve got the back brake working fine, but I’m having trouble with getting the front bled properly, and being as stuborn and as tight (read Scottish) as I am, I don’t want to shell out for one of those expensive vacuum pumps…plus I’ve heard they are not 100% proof anyway.
I want to try the trick where you zip-tie the brake lever to the bars overnight and tap the hoses and calpiers to dislodge any remaining trapped air, but am I meant to leave the resevoir cap and diaphragm in place overnight or should it be removed? I keep the bike outside under cover over night and don’t want the brake fluid to suck up all the moisture from the air and get contaminated if the cap and diaphragm are left off…so whats the deal?
The zip tie can work so long as you have got most of the air out, have you checked if you have a bleed nipple up by the lever, if you have, bleed it there first then go to each caliper then back to the top on so on till you get all the air out and you have a good firm brake feel.
If you fitted front brake lines direct to each caliper the above should be ok but if you’ve fitted lines with a loop from one caliper over to the other you might need to raise the caliper by removing from its mount and bleed it so no air is trapped in the loop, make sure you put a packer the thickenss of the disc between the pads if you have to do this though.
I find with brake hose replacement, take the calipers off and push the pistons right back, cap on as well. That usually takes the sponginess out. Make sure you bleed well, two people is a must. Pump several times, hold the lever, open the bleed nipple, as the lever comes back , close the nipple and repeat. I usually tie the brake lever for a few hours. I use a clear piece of tube, nothing fancy or expensive and a clear jar. My brakes are always spot on.
Having used and gotten used to a friends Mity Vac. They are great for getting fluid into a completely dry system - you know when no matter how many times you squeeze the brake lever you feel no resistance at all but the spring? That’s when the Mity vac is great But for getting that last bubble of air out, then manual method every time.
Oh and a Mity vac can use a lot of fluid if you’re not careful.
Never had any trouble with braided lines in the 30 or so years they have been available for bikes. As I said push the pistons right back, I have fitted hundreds of lines. No need for expensive high tec gizmo’s.
quick bleed tip, run some clear small bore hose (windscreen washer hose, air hose from fishtanks etc) from the bleed nipple up to the reservoir. pump and tighten the bleed nipple as you would normally do into a jar, until the fluid is circulating up into the reservoir, topping up as required. once you have liquid up to the reservoir you hold the hose beneath the fluid level and just pump, there is no way air can enter the circuit and any air bubbles in place get moved along and vent to atmosphere via the reservoir, its the quickest easiest way to bleed the circuit that I have ever found.
But for getting that last bubble of air out, then manual method every time.