Can't get it up at the rear....!!!

[Titch]

Right... now that I have your attention, I have a little problem... with my rear brake, in that no matter what I do to try to bleed the system I can't get any pressure on the pedal....

I've tried the conventional method of attaching a clear tube to the nipple, and putting the other end of the tube in a bottle in some more clean fluid, and then pumping the pedal... holding it down whilst opening the nipple, waiting for the fluid/air to come out, closing the nipple and slowly releasing the pedal agin... oh yeh, and this is done with the cap off the reservoir, and plenty of fluid in it so no air coming in from the top.

I have been doing this method for over 6 hours (on and off), and still got no pressure on the pedal.....

I have then tried taking the caliper off the bracket, and lowering it to the floor (releasing the line from the swing arm), and opening the nipple and just leaving it to allow the fluid to act with gravity to pull the fluid down the line... after bing left for a few hours, have tightened the nipple back up and pumped the pedal to relase any air which has now gone to the top near the reservoir/master cylinder, and then put the caliper back, and primed the sytem as above, but still no pressure...

I have then tried another method of back flushing with a syringe at the caliper pushing the fluid through and into the reservoir... at this the pads/piston closed up, and for a short time... I got pressure... however when went for a test ride, the first time I touched the pedal, nothing...

I have checked the entire sytem for leaks... put ptfe tape on all threads (nipples, banjo's etc..), it is a new goodridge braided hose, and new pads and disk.... At first I did get lots of air coming out ( to be expected with a new hose ), but now just get fluid coming out of the nipple into the tube, whenever I try to bleed it up...

So basically... I NEED HELP....!!!!

Thanks

Titch.

[Boris]

Have you considered the master cylinder seals? I had exactly the same problem with the clutch on a car. I could get it bled eventually but within an hour it had gone again.

What was it that made you start the bleeding in the first place?

[Titch]

What was it that made you start the bleeding in the first place?

Converting the rear end from drum brake to disk...

[StumpyFingers]

Does it use a slave?
If so is that working properly?

[Warthog]

Get e length of said clear tube, get a 20cc syringe from the chemists, suck up some brake fluid.

Connect the clear tube to the syringe at one end, to the caliper bleed nipple at the other (bleed nipple being open) and gently press the plunder feed fluid from the bottom of the system, back up to the master cylinder and reservoir, thus avoiding having to fight against air bubbles wanting to rise.

[Titch]

Get e length of said clear tube, get a 20cc syringe from the chemists, suck up some brake fluid.

Connect the clear tube to the syringe at one end, to the caliper bleed nipple at the other (bleed nipple being open) and gently press the plunder feed fluid from the bottom of the system, back up to the master cylinder and reservoir, thus avoiding having to fight against air bubbles wanting to rise.

Already done...

I have then tried another method of back flushing with a syringe at the caliper pushing the fluid through and into the reservoir... at this the pads/piston closed up, and for a short time... I got pressure... however when went for a test ride, the first time I touched the pedal, nothing...

Does it use a slave?

No it doesn't have a slave... just reservoir, to master cylinder then hose down to caliper....

In relation to the seals on the master cylinder.... it gets plenty of pressure at this point if you remove the hose and stick your finger over the hole, it almost pushes you finger off, then if you remove your fingerto let off the pressure then put it back... when you release the lever again it sucks down on your finger creating a vacuum effect, so based on this I can assume that the seals are ok...

[StumpyFingers]

Already done...


No it doesn't have a slave... just reservoir, to master cylinder then hose down to caliper....

In relation to the seals on the master cylinder.... it gets plenty of pressure at this point if you remove the hose and stick your finger over the hole, it almost pushes you finger off, then if you remove your fingerto let off the pressure then put it back... when you release the lever again it sucks down on your finger creating a vacuum effect, so based on this I can assume that the seals are ok...

What pipe are you using?
If it is rubber maybe it is flexing too much, else it could be a problem with the caliper.

[Titch]

What pipe are you using?
If it is rubber maybe it is flexing too much, else it could be a problem with the caliper.

The pipe I'm usin is from a brake bleed kit for a car, which uses one of those one way valves... great for cars, but sh*te for bikes, as you can't get enough pressure to force the fluid through, and it just forces it's way out of the side of the bleed nipple... but anyway, the pipe is up for the job.
What could it be with the caliper...

Latest.. I've just phoned a mate who has a garage nearby, and he said take it to him in the morning, and he will have a look for me... Just got to do the 1 mile ride with only front brake..(which is also very soft due to master cylinder on it's way out... not changed it yet..Doh...thats the next job...).

[AIRWOLF]

Use the banjo where the hose connects to the master cylinder as a bleed nipple.

The set up traps air at this point. . . . . put some rags to catch the fluid .

[sucram]

Hi
Rather than lowering the calliper, you could try raising it up as high as poss. This will help any air bubbles to rise. Keep the bleed nipple uppermost.
Also, if you have somebody else to press the pedal, you could try the old fashioned way. Open the nipple, shout down, press the pedal- close the nipple, release the pedal. Open the nipple and repeat ad nausium. I know its long winded and slow but it may help, especially if there is an air leak at the pipe on the nipple.
Have fun

By the way, on another subject, you posted some time ago about wheels from other models that would fit a TA. Do you know if an Africa twin front wheel would fit? Does the Dominator front disk not fit a TA?
Thanks