Back Brake Spongy, Help On Bleeding.

[DeeJ]

I had my back wheel off yesterday to change the tyre, and when i was kneeling down i stumbled and knocked the brake pedal down forcing the pistons out.

I got the pistons back into the caliper.

Fitted the wheel.

And now when applying the brake, there is no force pushing back against me. And the brake will only apply when the brake is pushed all the way down, which is almost impossible when riding as my foot comes off the rearset.

Been told air is in the system.

I have kept passing fluid through the system.

pushing the lever all the way down, undoing the bleed nipple, letting it run out, then tightening the bleed nipple, and then raising the lever back, and then priming the pedal and then keep repeating the process, but the pedal is still very spongy with no feel to it.

And suggestions.

As I need it sorted ASAP as I was planning on using my bike to get to the rally or going have to come in the Volvo which will be a boring drive.

[Guest]

you've probably left it alone so try it again, the air will have hopefully created a pocket in the caliper which will bleed easily, also check that there isn't 2 bleed screws on the rear caliper, could be you are bleeding one side and not the other..

rolling the bike and then applying the brake will help it settle too, but i don't recommend a ride to do this ...

and OUCH for your DAD...

[DeeJ]

Brake pedal is still going all the way down with very little resistance, and I have passed 6 full reservoirs of brake fluid through now, 3 yesterday and 3 this morning.

Just checked and there is only 1 bleed nipple.

I'm baffled

[Guest]

sounds like you have a leak, you need to check.. especially after your other thread about your dad getting trapped etc..

[DeeJ]

sounds like you have a leak, you need to check.. especially after your other thread about your dad getting trapped etc..

 

I've checked everywhere there is no leak at all.

There is just air in there which ain't coming out

[Guest]

heres how i do it.

need

brake fluid

clear tubing (bout 3 inches)

large syringe (vets/petshop)

fill reservoir with fluid.

fit tube to nipple, and srying to tube,

open nipple

pull on syringe this will pull fluid through, and air

no need to keep opening/closing the nipple.

or reverse bleed..

fill syringe with fluid, not reservoir, fit syringe as bfore but push fluid into caliper..

using a combination of the two means you can push fluid in, then leave for air to settle and pull air out...

[DeeJ]

Kk, I will go down petshop. Just going in for my theory test now

[Guest]

before you do anything....

how far back did you push the pistons when refitting them? all the way?

press the pedal fully 10 or so times it could be that you're not letting the piston move out to make contact with pads/disc, so its soft.

if its still soft, it needs bleeding again.

[DeeJ]

heres how i do it.

need

brake fluid

clear tubing (bout 3 inches)

large syringe (vets/petshop)

fill reservoir with fluid.

fit tube to nipple, and srying to tube,

open nipple

pull on syringe this will pull fluid through, and air

no need to keep opening/closing the nipple.

or reverse bleed..

fill syringe with fluid, not reservoir, fit syringe as bfore but push fluid into caliper..

using a combination of the two means you can push fluid in, then leave for air to settle and pull air out...

 

I have tried the method of pulling it out using the syringe but no change.

And then I tried to do reverse bleeding but it just won't go into the caliper, do i need to hold down the pedal to do this?

[Guest]

I have tried the method of pulling it out using the syringe but no change.

And then I tried to do reverse bleeding but it just won't go into the caliper, do i need to hold down the pedal to do this?

did anything happen when you tried pulling the fluid out?

are you getting any fluid out?

it could be you haven't opened the bleed nipple enough, this would be what is happening when you try to reverse bleed and nothing is going into the caliper.

the pedal doesn't need to be operated for either, just keep an eye on the reservoir as you'll either be emptying it, or if reverse bleeding the fluid will end up here.

[Guest]

even with the standard way you should get fluid with bubbles in, if your getting nothing at all, it suggests the nipple is closed.

[DeeJ]

I can draw fluid out with the syringe, but it just won't go in.

I'm going be taking it to my mate next week to have a look at

[Guest]

I can draw fluid out with the syringe, but it just won't go in.

I'm going be taking it to my mate next week to have a look at

you may have speed bleeders fitted, they have a built in valve that works one way to stop air entering the system.

[DeeJ]

I can draw fluid out with the syringe, but it just won't go in.

I'm going be taking it to my mate next week to have a look at

you may have speed bleeders fitted, they have a built in valve that works one way to stop air entering the system.

 

Great, what would be my other option then.

I have been working on it for 2 days now and burnt my head in the sun, so was ready to smash it up today.

I hate italian bikes, nothing is bloody simple.

[Guest]

if it has speed bleeders then you can't back fill.

try this, i have done it beofre and it worked.

you will need a bucket of soapy water handy as brake fluid will eat through rubber if left untreated, as it will with paint etc

remove the bleed screw completely.

fill the reservoir with fluid, and pump the brake, watching the bleed screw hole.

the air will be expelled from the caliper through normal means

when the brake fluid trickles out of the bleed hole, replace bleed screw.

you know have most of the air out of the system and will require a simple bleed.

let me know how you get on.

[DeeJ]

After 2 hours of working on it today, I have finally sorted it.

One of my pistons was coming out too slow due to a tiny bit of dirt stuck to the side of the piston.

All striped cleaned and put back together and working great, and it now bleeds with ease.

[j4ff]

Now remember to never use it again paint it red as a reminder.