Brake Bleeding for Dummies

Okay, so I've read the manual, and every article online, but for some reason I always have the hardest time getting it to work. There is no fluid in the lines at the moment, but no matter how many times I go through the process, the fluid just will not leave the reservoir.

Master cylinder and reservoir are brand new, brand new stainless braided brake lines, front brakes are dual caliper 2005 Ninja 636 brakes.

Technique I'm following...

1) Fill master cylinder reservoir
2) Fill a jar with brake fluid
3) place a hose on the nipple and into the brake fluid in the jar
4) with the nipple closed, pump the handle
5) with the handle pulled (on) loosen the nipple
6) release the handle
7) tighten the handle
8) repeat

Are there any fancy tricks that I'm missing?

you must bench bleed the master first

and with the hose arrangement you can leave the nippile cracked and just pump awaay

Unless the nipple threads are coated/teflon tape, air will seep back in past the threads.

What I suggest is to pump 3 times and hold. Then crack open the banjo bolt at the master cylinder - but have a rag handy to catch any fluid when it starts to come out. Repeat until it pushes fluid out of the banjo bolt. Then bleed as normal. Some air will rise in the hose and will want to come out at the master, so when you think you are done, go back to bleeding at the M/C banjo bolt to finish it off.

Brakes bleed?

Just an FYI for the first bleeders, brake fluid is detrimental to any unprotected surface emphasis on fresh rattle can paint.

teazer said:

Unless the nipple threads are coated/teflon tape, air will seep back in past the threads.

What I suggest is to pump 3 times and hold. Then crack open the banjo bolt at the master cylinder - but have a rag handy to catch any fluid when it starts to come out. Repeat until it pushes fluid out of the banjo bolt. Then bleed as normal. Some air will rise in the hose and will want to come out at the master, so when you think you are done, go back to bleeding at the M/C banjo bolt to finish it off.

Click to expand...

never had that issue just have the bleeder cracked not loose a full turn

+1 on the above comments. By and large, the difficulty is in just one place, a comparatively large volume of air right at the mc. Stuff a bunch of rags around the banjo at the mc and crack the bolt loose, pump the lever a couple of times and tighten the bolt with the lever compressed. Usually that reduces the air volume enough to enable the mc to start actually pumping fluid down the lines. Most brake lines are small enough i.d. that air in them does not bubble up to their top or a high spot so usually once that one bit at the mc is dealt with it's smooth sailing. There may be lots of air in the lines, but those bubbles usually just get pumped down the lines along with the fluid. The teflon tape is a great trick to help seal up the threads on the caliper bleeds, but it is pretty hard to not make a mess anyway. Once you get the mc to start pumping, you should start to notice some resistance almost immediately. Give it a few pumps, then crack the caliper bleeder with light pressure on the lever. close the bleeder before letting off of the lever. Repeat until all the air is out. For the record, the hose on the bleeder with the end submerged in fluid is not in any way needed except to keep the mess under control. In fact, if you don't care about the mess (and this way is hardly any more messy if you use lots of rags and are careful), simply remove the bleed screw altogether. Once you get the air bubble out at the master, just put your finger over the bleed screw hole and pump up the brake. Just press your finger over the hole tight enough to let air and fluid out, but not let air back in. You will bleed a single caliper perfectly in easily less than a minute - no kidding! Once you are done, let the lever go, remove your finger and replace the bleeder screw. Usually the only hurry is to keep fluid from dripping out - generally air is not likely to go back in but it is possible on some configurations. Someone makes stainless steel, teflon sealed spring loaded check valved bleed screws that solve pretty much all the unpleasantness but I can't remember who at the moment. Always thought that would be the ticket, but maybe a bit fancy for a fairly rare task.

Russell

At least that's the name on some I have here.

On a recent build the highest part is the M/C banjo and they refused to bleed cleanly, so I fitted VENHILL chrome banjo bolts with nipples from ebay. Problem fixed.

So, I'm working on something completely unrelated and this suddenly pops into my head:

http://www.speedbleeder.com/

So I come back to see the thread, and just had to check - indeed Russell has them too - looks like they may actually be from Speed Bleeder.
I thought they were all stainless, but evidently you have to specify - maybe they were only in stainless back when I was scoping them out.

Once I started thinking about it, I remember saving these guy's website (adults only - major bolt porn):

http://www.probolt-usa.com/titanium/titanium-motorcycle-special-parts/titanium-banjo-bolts/titanium-banjo-single-bolt-m10-x-1-00mm-with-bleed-nipple.html

Just in case the fancy bleeders aren't fancy enough! (have had occasions I wished I had a bleed on the mc! )

treitz said:

Okay, so I've read the manual, and every article online, but for some reason I always have the hardest time getting it to work. There is no fluid in the lines at the moment, but no matter how many times I go through the process, the fluid just will not leave the reservoir.

Master cylinder and reservoir are brand new, brand new stainless braided brake lines, front brakes are dual caliper 2005 Ninja 636 brakes.

Technique I'm following...

1) Fill master cylinder reservoir
2) Fill a jar with brake fluid
3) place a hose on the nipple and into the brake fluid in the jar
4) with the nipple closed, pump the handle
5) with the handle pulled (on) loosen the nipple
6) release the handle
7) tighten the handle
8) repeat

Are there any fancy tricks that I'm missing?

Click to expand...

This is what is causing your problem. By placing the hose in the fluid, you are creating an air trap. The hole in the master cylinder is very small, brake fluid is fairly viscous and the fluid at the end of the hose makes it so the air trying to escape into the reservoir (and thus letting fluid into the line) is trying to pull fluid up from the jar (which it doesn't have enough suction to do) and the viscosity of the fluid in the reservoir resists letting air through the small hole. It's like the bubbles that you see in a straw sometimes, where there will be a section of the straw with soda in it floating on a section of air about 1/2" above the level of the drink.

Try this: put the hose in an empty jar, and open the bleed screw. Just leave it open for a little bit. Let gravity do its thing and allow fluid to drip into the jar. With the end of the hose open to atmosphere, fluid will move down easier. It's similar to priming a pump. Once fluid starts coming into the jar, then put some fluid into the jar, and continue the way you were.


Another thing that may cause issue is a master cylinder banjo fitting that is angled up. This creates an air trap, as well, and you may have to bleed the banjo bolt on the master cyl. This is done similar to the bleeder nipples, but by loosening the banjo bolt.

"
Try this: put the hose in an empty jar, and open the bleed screw. Just leave it open for a little bit. Let gravity do its thing and allow fluid to drip into the jar. With the end of the hose open to atmosphere, fluid will move down easier. It's similar to priming a pump. Once fluid starts coming into the jar, then put some fluid into the jar, and continue the way you were. "


Unless you open the banjo nothing should drain into the jar with the bleeder open, if it does the master is bypassing and needs rebuilt.

Way over thought simple task folks, this turned into another "to many cooks" thread

Tune-A-Fish said:

Unless you open the banjo nothing should drain into the jar with the bleeder open, if it does the master is bypassing and needs rebuilt.

Way over thought simple task folks, this turned into another "to many cooks" thread

Click to expand...

Come, now, I thought you were way too experienced not to know how a master cylinder works! When the piston is retracted, fluid moves from the reservoir into the cylinder. when the piston is pushed in by the lever, it blocks the hole and pushes the fluid in the cylinder down the brake line. This is why if you have an air bubble in the line you need to pump it, and this passage also allows for expansion when the fluid gets hot. But fluid only ever moves between the reservoir and the master cylinder when the brake lever is released.

See the attached:

It REALLY helps if you put a loop into bleeder hose before putting it into jar of fluid. Zip tie it in position

"Come, now, I thought you were way too experienced not to know how a master cylinder works! "

Well I I I thought I was :-\ You see... most of the motocicle brakes have a dual plunger chamber, one pushes fluid to the caliper while the other is providing supply from the res, the fluid only passes by the front plunger as the brake wears and needs additional fluid, but will not, could not, should not "drain" past because of gravity pull.

Here are some pitcures, not nearly as experienced as yern.

Hmm. I guess you shouldn't be able to compress the caliper pistons into the calipers when the lever is released, then.......

8ball said:

Hmm. I guess you shouldn't be able to compress the caliper pistons into the calipers when the lever is released, then.......

Click to expand...

Not enough to service (replace) the pads, and as long as most pads are on, unless were talking racing or less than average rider doing stopies or canyon runs, but that is a whole new set of rules... changing brakes with a bunch of miles on I would inspect the guts in the calipers anyhoo and replace the rubbers just to freshen things up so the the banjo would be DC'd. It's not a C-clamp job

I am just talking about the mechanism. If the passageway between the res and the MC piston is blocked when the lever is released, then you should not be able to spread the pads. The way you are describing the functionality of the MC, it has no possible way of operating.

8ball said:

I am just talking about the mechanism. If the passageway between the res and the MC piston is blocked when the lever is released, then you should not be able to spread the pads. The way you are describing the functionality of the MC, it has no possible way of operating.

Click to expand...

You might be thinking that the more you pull the tighter it gets? Not so much... the front plunger never draws back behind the inlet port, the front plunger is designed to bypass in reverse and pressurize under load, the fluid in the chamber between the two plungers is supply, when you release the brake you release pressure on the pads, fluid moves back and forth.

I don't know, maybe I can't explain it well, go open the bleeder on your caliper and let it sit for a week and see how much fluid is on the floor, other than a few drops from some pressure release, I would say... Nada or your MC is weak.

If you want to win, I understand... You Win!

I digress.

when the master is released there is a direct passage ,it woont work otherwsie.it is one of the fundamentil principluls of the system
you can see it when pushing back the pucks, you can even get a shot of fluid in yer eye
if you were to remove the master cap then the flluid will drain all the way out, the master cap installed can provide in some systems just enof resist to quell full drainage

Tune-A-Fish said:

Not enough to service (replace) the pads, and as long as most pads are on, unless were talking racing or less than average rider doing stopies or canyon runs, but that is a whole new set of rules... changing brakes with a bunch of miles on I would inspect the guts in the calipers anyhoo and replace the rubbers just to freshen things up so the the banjo would be DC'd. It's not a C-clamp job

Click to expand...

you can push the pistons all the way in and service pads without doing ANYTHING else not even requied to bleed the system
in any system(abs maybe the exception) the pads can be bottomed out simply by pushing on them in