1st Part- The calliper makes enough pressure to close the pads, lever releases and pistons pulls back the way they are suppose to when lever is released-then less closing power with next press-then more less power and then finally when bottoms out a tiny bit of brakes, releases back to normal position and when you pressing again no pressure. lever moves as it suppose to but the pads nothing....
Yeah. Progressively less braking power caused by progressively less fluid pressure. This could be caused by that air bubble I was speaking of getting pumped from the MC into the brake line. A little more air each time you hit the brake. The air is displacing the fluid that is supposed to be in the line.
The pedal is not returning to the UP position on fluid pressure like it should, it is returning on the safety spring and I believe there is a second tiny spring on the brake light sensor and that pulls the pedal up too. It should go up on fluid pressure alone if you have fluid pressure.
With normal driving it works perfectly all the time.... Like 100%.........So can it then be that the bubble you mentioned then first gets the gap to move through when extreme braking is used? And then for normal riding the bubble just settles on the upper parts of hose/ressevoir like you mentioned and then does not get that much of force with normal riding to make its way through to the callipers to cause loose of pressure?
That's exactly what I'm thinking. The bubble is staying in the MC under normal braking (or who knows?? maybe is not in MC but is stuck in the down spout from the reservoir and the bubble won't float up to the reserevoir for some reason??). When you apply the brake hard, the plunger in the MC is extending far enough to draw part of that big bubble into the brake line. The air stays in the brake line reducing pressure because air compresses easier than fluid. The next time you use the brake, more of the big bubble is pushed into the brake line. Now even less pressure. You progressively need to opperate the brake pedal at more throw to produce enough pressure to close the pads. ...until you are at full throw and there is too much air in the line to create hardly any pressure at all.
Then you let it sit a while and the air in the line rises back up to the big bubble. Now you have brakes again...unless you get on the brake hard, then you start pushing air down into the line again.
My gf's brother suggested that the brake fluid may be boiling when used hard and aggresively? Which then also forms airbubbles? Possible? Yes? Or no likely?
Possible but you would need to be on the brake exceptionally hard and I'm sure repeatedly before you noticed brake fade from boiling. We do not hear about this except in road racing track use. It would produce the same symptoms you describe and it would go away on it's own like you have described.
That's INSANE brake use on the street. It's possible though. I'd think you would likely be liftig the rear end up some under that hard of braking. It is possible though.
They make DOT5 brake fluid for high temp race use. It is normally purple in color. It does work better if you get your brake fluid that hot but it is NOT for use in systems that not designed for DOT5. It will leak past seals. Might cause permanent damage to rubber parts. I do not believe the busa's stock system can tolerate DOT5. I know for a fact DOT5 will leak in the ZX-14's brakes. Make sure you do your research if you try that stuff.
Steel braided lines would also help if you are getting your brake fluid that hot.
I think we did bleed it the way you described.... Surely did not let go of pedal while bleeder was open that i am sure of....
We closed bleed-pump pedal until feeling normal, then open bleed-gently pressed down lever till it reached the bottom and while holding it there closed the bleed-pumped it again till normal feel-opened bleed and gently bottomed the lever and closed bleed while it was bottomed... Fine right?
That sounds like the correct procedure. The only thing I do differently is that I pump the lever and then hold it before I open the bleeder. Sounds like you are pumping the lever and then letting it go, then openning the bleeder and pulling the lever. I do not think it would make a difference if you did it my way or yours. Just don't let go of the lever when the bleed is open.
Maybe you do have boiling fluid....damn! I really doubt that though. Even if you lock the brake one time, that shouldn't boil the fluid so you have partial braking 2 seconds later.
I must say, I've never experienced brake fade even on a road racing track. I am not skilled enough to use my brakes that hard though. I rely much on engine braking because I'm slower. If you are on the brake hard enough to produce brake fade I would think it would take more than one hard application of the brake.
On the topic of brake fade from fluid boil, it is also possible you have fluid contaminated with condensation. Water boils much easier than the lowest grade of pure brake fluid. If you have water in your system, it would lower the boiling point and also could cause rust. As someone mentioned before, brake fluid is very hygroscopic. It draws moisture from the air into it and there is an air pocket in your reservoir that could accumulate condensation which would run into your fluid. This is why it is a good precaution to never add brake fluid from a bottle that has been opened for some time to your system. If the seal on the bottle was broken a week ago, moisture could have gotten into the bottle. If the bottle was partially used, there is a large pocket of air that can accumulate condensation. So buy a small bottle and dispose of the unused portion properly.
I have used VERY old previously opened brake fluid many times. Never had a problem but it is a poor habit if not for the boiling protection, the rust hazard protection.
Never heard of TNT, Pro Parcel or FLYT. UPS and Fedex are quite common and I seldom see a DHL truck. Probably no need to weigh or measure anything, just figure on a couple pounds and about 8”x 8” x2”. I’ll also need your country and postal code for an estimate from my end.
and the post office would cost just under $70 for a two pound package with no delivery time listed for fedex and eight days for the post office delivery. I’m going to town next week so I can try another outlet in person to see if the prices are any different. From here to there is (only) 9,679 miles.....
