Brake Bleeding.....help.

[VA]

This is more of a let off steam post, but if anyone has any input then please make a post.

I've decided to run dual lines on the front of my GK73A, gets rid of the splitter which I never liked. Anyway, I reused the double banjo bolt from the splitter on the M/C and both lines down to the calipers, washers are new also. Lets not forget a complete strip/rebuild of both front calipers. For the life of me I cannot get a firm brake lever, bled and bled until there is no more air. At this point I thought I'd try something so I quickly removed the double banjo bolt and replaced it with a single banjo bolt and one line, quick pump & bleed, hey presto I have a firm lever, did the same with the other line and the same result, brakes bang on, as soon as I put that double banjo bolt back and both lines I'm back to no lever, I've cracked the Banjo bolt at the M/C a few times but to no avail.......where is the air I ask myself, no fluid leaks. Anyone got any ideas, how can a double banjo bolt cause this trouble, can they get defective. If I can get a firm lever with single bolt/lines what difference is double/bolt lines creating.

[Jaicen]

Have you replaced the copper washers? They're not meant to be reused, though I can't imagine they would be letting air in.

[mattley87]

not forgetting three copper washers for the double banjo are ya???

[VA]

Thanks guys, but it cannot be down to the washers, I have a bag full of those and everywhere that needs one gets one, this is not to say that in frustration a washer could be overlooked and left out by mistake, but this is not the case. I'm gonna have another swim in brake fluid today and see if anything changes.

[stripes1976]

Have you pushed the pistons right back in. Removed the calipers and tried rotating them to see if you have can expel air? Or if still no luck removed the whole front brakes and bled them off the bike (my prefered method)

[Sligeach]

best best it to reverse bleed it using a syringe.

look on ebay and there are lots of them, nice an cheap too

[neilwilson]

Hi mate, did you overcome this problem. i have exactly the same scenario on my nc29.

[monkers]

Sure this must have been solved by now, but if you say that you have the same issues then...


You run the brake lines with single banjo at both ends + new copper washers it's fine?
You have tried single lines on both callipers and both callipers work?
If you introduce the double banjo bolt it fails? correct?

Just by elimination it is telling you that the double bolt is at fault. Yes they can wear out/develop a fault, they are mechanical so have a finite life.

If all of the above is correct then you need a new double banjo bolt. They are cheap as chips, just be careful that you get the correct size/pitch.

HTH

Ian

[neilwilson]

For everyone information who may have a similar concern in future, i couldnt get a firm brake lever with a dual banjo fitting no matter how much or how hard i tried. I tried several dual fittings all were no good??? anyways i read somewhere on the interweb to keep the lever pulled over night. so i tied lever back and left it overnight. tested it the next day and lever was solid, brakes were 100%. whatever happened to the air in the system....god knows? i did remove the resevoir cap before releasing the lever, whether or not all the air rose to the top of the system is unknown to me but never-the-less sorted now.