am gonna be bleeding my brakes soon and have a couple of questions before i start....

why do you only squeeze the lever 3/4 of the throw/travel to pump fluid through and not all the way? is there a pecific reason for this? and if i'm completely draining the system is there anything i should be aware of? or do i just do the same as the bleed until is empty?

seeing as though i change the pads regulary on the ZX-7 i brought some copper grease, only problem i have is that i dont know where to apply it i know you use it somewhere but not sure where exaxtly. is it on the end of the pistons?

think thats it all...

Mark.

Mark,

Bleeding brakes manually is gonna be a pain. Ideally you need some sort of suction pump to pull the fluid (and any air bubbles)through the nipple.
Air floats to the top and just pumping the levers isn't gonna get the little bu$$ers out of the system easily.
I haven't tried this but if you can get the calipers off and keep 'em at a level higher than the reservoir then you should be ok. Alternatively if you can take the brake lever off and fit it to a piece of 22mm tubing, keep the reservoir at a level LOWER than the bleed nipple, air bubbles rise to the top and make bleeding easier.

Re copper grease I never bothered with the stuff on brakes, but I suppose you could smear a VERY THIN coating (brakes get hot and you don't want the stuff melting all over your brakes) on the backside of the pads. Just go easy on new pads for the first few miles. You want to bed them in correctly.

Originally posted by cokeysblokey
am gonna be bleeding my brakes soon and have a couple of questions before i start....

why do you only squeeze the lever 3/4 of the throw/travel to pump fluid through and not all the way? is there a pecific reason for this? and if i'm completely draining the system is there anything i should be aware of? or do i just do the same as the bleed until is empty?

seeing as though i change the pads regulary on the ZX-7 i brought some copper grease, only problem i have is that i dont know where to apply it i know you use it somewhere but not sure where exaxtly. is it on the end of the pistons?

think thats it all...

Mark.

Hi Mark,
The trick for bleeding is that you don't want any air to come in the circuit from the bottom while you have the bleed nipple open or from the top (from the reservoir).
This is done easier if you don't use the whole lever travel.
I do the following: Press the lever with one hand with bleed nipple screw tight. As if you were applying the brakes on normally. While constantly applying pressure, I open the bleed screw. At this point the lever goes towards the bar. Then close the circuit again BEFORE the lever touches the bar. This way I ensure that I don't allow any air to come in the circuit from the bleed nipple. After closing the bleed screw, pump the lever a few times (4-5) until the lever comes back to its original position.
Repeat until you have no more bubbles coming out ( if you just want to blee the air out) or until you get all the all the old and dark fluid out (in case you are changing fluid).
Before the level of fluid in the reservoir falls until the point where you could get air in, add fluid. If you are changing fluid you'll have to repeat this many times.
Use a cloth or something to prevent fluid coming in contact with the area surrounding the fluid reservoir (brake pump). As you pump the lever with the reservoir cap open, some fluid drops migh jump out, so make sure you have the area around it covered with some cloth or other suitable material at all times.
Be careful because the fluid eats colour for breakfast!
When I want to change fluid completely I remove some fluid from the reservoir with a syringe to accelerate the procedure.
There are bleeding systems in the market, but I always do it this way It's cheaper and more satisfying.

As for the copper grease, you got it right. Apply a small amount between the brake piston and the pad.

I hope what I described above is clear and helpful

Aris

thats brilliant thanks...

i've gone and brought myself a brake bleeding non return valve to try out. have you had any experience with these things?

Mark.

I've bled many brake systems over the years and have had great luck using a vacuum bleeder. Makes a 2-person (or 1-person w/ difficulty) job a snap and makes it easier to keep from spilling that nasty paint-eating brake fluid on your wheels!

As for getting the tiny bubbles out that apparently cling to the inside of the hoses and refuse to be bled out the conventional way, try clamping your brake lever closed for 24 hours or so (48 hours is better, but tough to do doing riding season) while occassionally tapping on the lines to free up the bubbles. They'll eventually rise up into the master cylinder and come out of suspension. Even when I believe I've got all the air out, using this trick convinces me otherwise as the lever ALWAYS feels just a little bit harder after doing it. I even did it w/ my brand new ZR as soon as I got it home and, sure enough, it made a difference.

I've never done this w/ a rear disc brake...one, because clamping it shut is difficult and two, because IMHO most of them are too sensitive anyway and having "only" 95% of the air bled out may prevent them from locking up too easily on slippery roads. Of course, I get enough air out so you don't have to "pump them up" when braking hard. (I used to help a friend w/ his racing go-kart and we always introduced a tiny bit of air into the brakes to make them less sensitive when he was racing on dirt.)