brake bleeding syringe method stil spongy advise pls

[oldgreyandslow]

I've run into a problem bleeding the front brakes.

I have new HEL lines fitted, calipers overhauled, new seals, clean pistons etc, the old pads are back in as there is plenty of meat on them and the pistons are pushed right back.

I connected a syringe to the left caliper, opened bleed screw, pulled the syringe back a bit and fed fluid in from the top, retightened the bleed screw and did the same on the right, went round them both a couple of times.

Each time I also drew a little fluid through with the syringe.

Pulled the lever many times and eventually the pads were pushed against the discs.

Went round the bleed screws again. Attached the syringe, opened the bleed screw, pulled the syringe back (opened it) and let some fuid through. There appears to be a bit of air at the top of the syringe though where the rubber tube is fitted to it.

I've done each caliper a few times now but the brake lever still feels spongy.

Any ideas where I'm going wrong?

Thanks

[ibby4585]

I use the syringe method and I never seem to get the lever rock hard.

The only thing I can suggest is after you have used the syringe to draw fluid through, bleed them normally until no bubbles are visible. Once done bleed it from the master cylinder. ( rag around the hoses, spanner on the hose bolt and fingers on the lever, press the lever and loosen the bolt do it very quickly and do it up not leaving go if the lever obviously.

Fill the Res up and and leave the lid loose and then cable tie the front brake up and leave it overnight. You will have more brake afterwards.

But your problem is air in the system without doubt.

Hope this makes sense.

[The Novice]

From memory I did it the other way.

Filled the syringe with fluid and pumped it in through the bleed screw (via a piece of tube obviously) - that seems to expel the air upwards a lot easier.

after doing that I then bled them in the normal way until the lever was no longer spongy. Sounds easy - but i remember it was a ballache to get all the air out.

[oldgreyandslow]

Thanks

I have now bled them the normal way, still a bit spongy so have tied the lever back and I'll leave it overnight and see how it fells then.

[scooble]

I find cracking off the banjo bolt at master cylinder helps when squeezing the lever to get the air bubbles out.

[V4beermonster]

Did you prime the master cylinder ?

[ibby4585]

I find cracking off the banjo bolt at master cylinder helps when squeezing the lever to get the air bubbles out.

Well obviously, as there would be no point otherwise would there!

[scooble]

Duh!

[oldgreyandslow]

Did you prime the master cylinder ?

No, I didn't. How do I do that? Or do I need to now it's all tied back?

[V4beermonster]

Iwith pipes disconnected from M/c pull brake lever and then put finger over the hole where pipes attach, release brake lever, do this over again until fluid is coming out the M/c then attach lines and bleed the normal way. Priming the M/c removes any air from the union and lines which are real pigs to get out otherwise. Also it may be needed to rest the fluid for 24 hours as you get little air bubbles, resting lets these join into bigger air bubbles. I only use DOT5 brake fluid in my bikes it is more expensive but has a musc higher boiling point, not hydrosorbic and best of all does not strip paint,