Front brake problems

[unit_mx]

G'day all
Just got my new front brake system and the thing does not seem to work braking wise.I've tried bleeding via taking the bleeder screw out of the slave cylinder then pumpin the brake lever so that the brake fluid comes out then held the lever in put the cap on the screw to seal it from air then put the screw in while still holding the clutch and still nothing ,i've tried it a few times with still nothing.everything is set up right ,the pads are on the disc ,the line is connected to both the salve and master cylinders.There's no grab in the lever just pulls back with out any tension and the bike roles normally with it on.Does anyone one know whats going on here? am I blleding it incorrectley?

 

[unit_mx]

sad old thread this one.someone must know somethinnnnnnngggggg

 

[THUMPY125]

its frustrating isn't it mate, got the exact same problem but with my rear brakes, the bloody things are brand new as well. i think i may have blown the seals so they aren't sealing, well at least the top one. pull the thing apart and check the cup seals on the piston and see if they are worn. then check if the system has a leak in it as it won't hold pressure if there is a leak.

hope this helps.
Callan

 

[pegleg]

You don't need to take bleeder screw out, just loosen it half a turn, and then Tighten again.
I am sure your getting **** loads of air in when you are trying to get the screw back in.
Give that ago and let us know how it goes.

 

[THUMPY125]

i don't think its as simple as that, are you attaching a tube onto the bleeder valve and then placing the other end into a jar or brake fluid, if not you should other wise you'll be sucking in more air.

 

[cass38a]

The best way is to use a large (60ml) catheter tip syrenge and some plastic tubing and inject the fluid in from the bleeder screw (start with a empty master cylinder). This forces all the air up (air prefers to rise just look at what happens if you fart in the bath) close the bleeder when the master cylinder is full and presto. Just ensure that you have no air in the syrenge when you start)

 

[Mack]

Thats the best way I've heard yet for filling these brake systems...brother in law's a nurse, gonna get me one of them...

 

[cass38a]

You can get them from a chemist as well, just make sure that is a chather tip not one designed for a needle.

It also helps if you straighten you brake lines so that there is no pesky high spots for a air bubble to get caught in.

Its also possible to suck the fluid thru using the syrenge to save squeezing the lever but as i said air bubbles prefer to go up.

 

[kaneo]

The best way is to use a large (60ml) catheter tip syrenge and some plastic tubing and inject the fluid in from the bleeder screw (start with a empty master cylinder). This forces all the air up (air prefers to rise just look at what happens if you fart in the bath) close the bleeder when the master cylinder is full and presto. Just ensure that you have no air in the syrenge when you start)

Spot on! This is the only way to bleed brakes that really works. Go to a vet clinic they have big *** off seringes for horses and cows that hold shitloads of fluid so you will only need one go at it.

 

[cass38a]

There is no point doing it unless you have a large one, as kaneo said you need to do it in one go. I never thought of getting one from a vet.

 

[kaneo]

Yeah the vet clinic doesnt look at you as if you were a junkie like the chemist does

 

[50s BRotherhood #1]

did u get it goin mate?
or am i goin to hav to come over n do it 4 ya...lol... i do it all the time at work..

 

[cass38a]

Yeah the vet clinic doesnt look at you as if you were a junkie like the chemist does

Bodybuilders use steroids designed for farm animals so the vet may think you are about to get on the juice.
A catheter tip does not fit a needle so its unlikey that anybody would think you a a junkie. I use them everyday (I have to feed my daughter by injecting food directly into her stomach) and buy them by the carton so that is how I came upon them.

Let us know if it solves your brake problem.

 

[unit_mx]

Thanks heaps fellas for all the tips ,i'll give it ago tommorow or somethin anyway gettin a big steroid/junkie needle is no worries my mums a nurse so should be easy gettin one ,i'll let ya know how i got on.

 

[mech_eng_matty]

Bit of a belated reply this one boys, but there is also another way to bleed brakes if anyone is interested.

I have never heard the syringe technique, but thats a great idea, makes a lot of sense, my way uses the same principle of pushing the air up to the top but in reverse!

Take the caliper off the fork and lift it up so it is above the master cylinder on the handlebar (try to keep the brake line as straight as possible so you get a clear passage of flow). It can be a bit tricky coz you are now going to bleed the system with the caliper above the master cylinder so it can sometime tend to be a 2 person job. Also, make sure you have something wedged in between the two brake pads where the rotor sits otherwise your going to have a fun time pushing those little pistons back to their home position when you go to put the caliper back on!!
Once you've got the calliper in a good position above the master cylinder, connect a clear tube to the brake bleeder screw and run the other end into a cup/empty vegemite jar/glass or similar.
Fill the master cylinder up with fluid to its fill line. Squeeze the lever in and out until you start to feel a good amount of pressure in the system and then hold it in!!! While your holding it in, get someone else (or if on your own just put a rubber band around the bar and lever to hold it in) to turn the bleed screw half a turn. All the fluid and air will come out of the calliper (you'll see the air coz it'll be little bubbles in amongst the oil). When the pressure has dropped off, tighten the bleed screw again and repeat the process of pumping the lever till tight, then bleed, pump the lever till tight then bleed. Continue this until there is no air coming out of the system. Be sure to keep the fluid in the master cylinder topped up coz its a real bitch when you spend 10 mins bleeding only to realise the reason your getting air is coz the master cylinder is empty!! HAHAAHAH.

After bleeding if you still have no pressure in teh line, you've got an air leak somewhere (or for that matter if the air just keeps coming out when bleeding). Check all the hoses for splits and check all the banjo bolts for loose ones. Short of this, i'm stuffed if i know! You could have worn seals in the caliper but its unlikely if they're pretty new.

Oh, one more thing, when selecting a cup/vegemite jar/glass, make sure its clean coz if its real clean you can re-use the brake fluid that comes out while bleeding!

Cheers