problems bleeding front break

i cant get my front break to bleed at all ive tried and tried,

first off the seal in the master clinder is huge when pushing in it jst scrunches up in the middle, should it be that big.?

i fill the m/c to maximun mark then put the cap back on i can then feel a tiny amount of pressure, then wen i try bleeding it dissappears, it smeam's as if its drawing in air from somewhere , ive tried using the vacume thing aswell but still nothing, i think thats theres air coming in from somewhere because when using the vacume it just keeps bringing through air constanly way more than normal, i cant notice any leaks or anything, where should i be checking or am i doing something wrong.

any adive will be great

here is what i do.took one of my wifes large seringes(for her horses.I don't think she uses it on herself)Attached a small hose on it.you need the same diameter as the bleed screw.Draw in the fluid,put it on the bleed screw,loosen the screw,push in the plunger,tighten the screw before removing the pressure.You might want to loosen the cap also.works for me

I've had trouble also, especially with the stock brake hose that loops under the fork, the syringe method works the best, take the cover off the master cylinder and force the fluid up from the bottom, then when you are done pull the lever in part way and tie strap it to the bars and let it sit overnight so the air can rise to the top and it should be OK.

make sure your pistons arent sucked all the way in as well... if they are too far in they will actually block the passageways for the fluid to fill the caliper and push the pistons... just a thought

I had this same problem on my 03 450 and it was the master cyl i rebuilt it and that took care of the problem. How i found this out was i took the hose off on the master cyl on the bars and stuck my finger over the hole ( bench bleeding) and it would not build pressure.

Hope this helps

make sure your pistons arent sucked all the way in as well... if they are too far in they will actually block the passageways for the fluid to fill the caliper and push the pistons... just a thought
Not possible.
Not possible.

maybe not on this model, but believe me it is... after you've seen something happen in person countless times it starts to become true :banana: In school when it came to bleed brakes I dont know how many people wasted a full 5 hour class bleeding brakes only to find out they didnt pop the pistons back out after servicing them... Just thought if he had possible worked on that end of things it may have something to do with it, sorry you disagree

maybe not on this model, but believe me it is... after you've seen something happen in person countless times it starts to become true :banana: In school when it came to bleed brakes I dont know how many people wasted a full 5 hour class bleeding brakes only to find out they didnt pop the pistons back out after servicing them... Just thought if he had possible worked on that end of things it may have something to do with it, sorry you disagree

The caliper pistons of the Aisin units used on Yamahas will not occlude the feed ports when fully compressed. In over 35 years as a professional, I never encountered one on any vehicle that did.

thats cool man, just letting you know what i've seen as well :eek: Not trying to start anything just trying to help, sorry bud :banana:

been told that i could have a air lock any adive on how to remove this air lock from the hose

You never said why you needed to bleed the brake in the first place, but boldly assuming without any reason to that your system is correctly assembled and in good health, the front brake should bleed by gravity.

The top seal is a bellows and should fold all the way back to a flat appearance. Open the reservoir and fill it leave the cover off. Open the bleeder screw and leave it open. Position the bars so that the bore of the master cylinder is horizontal to the ground. If fluid will run from the reservoir down and out the bleeder, just keep an eye on the fluid level and add more as needed to prevent it running out. When no more bubbles appear at the bleeder, close it.

If the fluid will not start down on its own, "tickle" the lever a little (moving the master cylinder plunger just a little, then letting it return) to get any air sitting in the fill port to burp up and out into the reservoir. Once the flow starts, let it go as above.

Once you've closed the bleeder, turn the bars slightly so that the hose end of the master cylinder is lower than the other, and move the lever slowly a short way, looking for any further air sitting in the bore to be forced up and out the fill port. If none is found, or once it seems gone, try the brake.

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