NC29 Brake Bleeding help please

[lloydspencer]

I have rebuilt my calipers with new pistons, seals pads and braided hoses.

I bled the brakes until there was no air bubles but there was no pressure in the system at all! So I rebuilt the master cylinder as well.

I have been pumping the fluid through making sure that no air was being sucked in at the calipers end.

How ever there is fluid being pumped through the system with no bubbles yet there is still no pressure what so ever. The pistons havent moved or anything!

I would love to get this fixed and ready to ride for my day off on tuesday!

[yeurman]

"The pistons havent moved or anything!"?????

Do you mean they havent moved out to push on the pads? Have you made sure there is no air on the master cylinder as this is usually where air is trapped.

Do you have two hoses from the Master, one to each caliper?

Crack open the banjo on the master cylinder while slowly pulling in the brake lever, have a rag ready to catch fliud. You will most likley have air there. Make sure to close off the banjo before releasing the brake lever.

Then fully bleed again.. lets us know how you get on.

Col

[Davez29]

Ok i had that problem while refurbing my calipers and brake line.

The way I sorted it was back bleeding them . Using a syringe take some out of the master cylinder, now using some plastic hose over the caliper nipple and syringing clean fluid up through the calipers first. This helps stop any air in the caliper and opens the pistons on to the discs. Start on the nearside disc first you may have to syringe the master cylinder as it will fill up occasionally. Finally bleed as normal. All should be well.

[cbr400rrn]

I pulled the fluid down the lines from the master cylinder to the caliper using a syringe (50ml syringe) but have heard of a lot of people using the technique that Durka Durka describes

[lloydspencer]

I bled the master cylinder, syringed into the calipers and nothing.

I finally asked a friend who is a car mechanic to bring a pressure bleeder and just sucked brake fluid until eventually there was something.

I manually bled them until there was a decent amount of feel.

They still are not how I would expect freshly rebuilt everything to feel.

Possibly disks are slightly worn.

I have done 500 miles now and bled twice, a couple of bubbles have come out.

Brakes are now a lot stronger. but possibly not perfect due to the disks.

[Davez29]

I think you may still have an airlock somewhere, try the master cylinder joints as mentioned above. Did the pistons move out when you reverse bleed them?

One other thing I noticed while doing my brakes, having small hands I have the adjuster set right in and at first it felt a little bit spongy, making me bleed a couple of times with no change. But when moving this span adjuster out the brakes were pretty solid with no spongy feeling, moving the adjuster back for my small hands the brake lever felt a little spongy again. Maybe your getting that?

[dunkenb]

Try tying the brake lever to the bars and leaving over night the pressure and open master cylinder gives the air time to rise . Worked on mine a few times over the years?