[locksmithuk]

Hi all

I was brake-bleeding last night using a Little Bleeder (for those of you outside the UK that means a plastic tube containing a one-way valve to avoid drawing air back through the bleed nipple during bleeding), and I've had some problems.

First I flushed & replaced the old brake fluid, taking care not to let any air in. Brakes tested, all good, smiling like a Cheshire cat.

Then I had second thoughts & decided to clean the pistons & caliper, so I had to go through the bleed process again, this time from an empty system. This is where the problems began: after pouring in new fluid into an empty system I can't get any pressure in the system when squeezing the brake lever - it's all spongy. I know the calipers are full of fluid because my Little Bleeder draws up some into the plastic tube immediately.... but it falls back into the nipple straight away.

There's obviously air being drawn into the system, and I think it's through the threads around the slightly-open nipple. I've tried everything to get rid of the excess air, from the old-fashioned way (open nipple with half-turn, squeezing brake lever, close nipple, release lever, repeat), through to quick pumping until there should be no more air in the system at all (or my lungs).

I'm going to try to find a way to wrap some teflon tape (if I can find any) or blue tack (as long as it doesn't stick to the threads) to seal the area around the nipple.

Does anyone have any other bright ideas?

Cheers
Darren

[ghbzorro]

Do NOT use teflon tape or goo. Work through the system and find where the real leak is located. And be patient.

[HondaGalToo]

When I've filled a system from dry, I've had to use a MityVac to get things going, then go back to regular bleeding. It can take quite awhile to get things moving from dry. One tip I'd heard but never tried, is to take a syringe with brake fluid, and push it from the bleeder nipple up to the reservoir.

[locksmithuk]

Originally Posted by HondaGalToo

When I've filled a system from dry, I've had to use a MityVac to get things going, then go back to regular bleeding. It can take quite awhile to get things moving from dry. One tip I'd heard but never tried, is to take a syringe with brake fluid, and push it from the bleeder nipple up to the reservoir.

Thanks for the reply. Yes, I've heard of syringing bottom-up, and I have a large one to use (a syringe I mean). Will give it a go.

Thanks

[denzee]

I've had similar problems and I think the problem is, air in the line naturally wants to go up or float in the lines. You are at the bottom (caliper) and trying to pull the air down opposite to the way it wants to go. I found let it sit overnight so the air has time to travel upstream and then bleed your master at the bleeder valve and the banjo line if nec. Then bleed the calipers again the manual way. It may take a couple of days but I was amazed the air that came out from the top.

[locksmithuk]

Originally Posted by denzee

I've had similar problems and I think the problem is, air in the line naturally wants to go up or float in the lines. You are at the bottom (caliper) and trying to pull the air down opposite to the way it wants to go. I found let it sit overnight so the air has time to travel upstream and then bleed your master at the bleeder valve and the banjo line if nec. Then bleed the calipers again the manual way. It may take a couple of days but I was amazed the air that came out from the top.

Nice one Denzee. I thought about that option as I was scratching my head about it this morning. Makes sense when you describe it like that. I also think I may not have started with a completely empty master/reservoir, so that'll probably be it.

Cheers

[sheepofblue]

Originally Posted by HondaGalToo

When I've filled a system from dry, I've had to use a MityVac to get things going, then go back to regular bleeding. It can take quite awhile to get things moving from dry. One tip I'd heard but never tried, is to take a syringe with brake fluid, and push it from the bleeder nipple up to the reservoir.

though mine was on a 1000RR oh and I added a speed bleeder on the top to my RC

[segiano]

Originally Posted by locksmithuk

Nice one Denzee. I thought about that option as I was scratching my head about it this morning. Makes sense when you describe it like that. I also think I may not have started with a completely empty master/reservoir, so that'll probably be it.

Cheers

I would also suggest you use a tie-wrap or something to hold the brake lever down over night. There is a check valve in the master cylinder and by holding the lever down, bubbles in the line can escape into the reservoir. I used this technique and the brake lever was rock solid. Good luck

[bulldog12]

try bleeding at the banjo bolt (heard this has caused many a problems) :thumbsup:

[rinker954]

Originally Posted by bulldog12

try bleeding at the banjo bolt (heard this has caused many a problems) :thumbsup:

+1

[flipsidenv]

Replaced the brake lines yesterday and after trying to bleed the brakes I was still getting nothing. I had a piece of clear flexible tubing on the bleeder, filled a large syringe with brake fluid, opened the bleeder, pulled the brake handle and tried forcing fluid backwards through the bleeder. Did this on both calipers. I never saw any bubbles or fluid come back through the reservoir (might have missed it while looking at the tube) but afterwords they bled fine. Handle was solid.

[locksmithuk]

Thanks all. It took a while but in the end I resorted to a syringe and bottom-up fluid injection. Fine now.

[LoopyLee]

I had mine to do as one of my callipers was sticking and had to be sorted out.

We tried bleeding the brakes the normal way, left it to sit overnight so any bubbles could work their way out but with no joy. We ended up having to syringe the system from the bottom and it worked a treat.. My brakes are now working brilliantly..

The advice on this thread was excellent, thanks everyone

[johnx144]

i used the little bleeder myself for the first time. the valve worked but i found it hard to get a good seal at the bleed nipple, so i had some fluid dripping out as i pumped!

[two feathers]

Can somebody please tell me the best way (The right way) to bleed a brake system? I posted comments before about having a bit too much travel through the lever than I would prefer, and went on to describe how I drained the old fluid and bled through a couple of reservoirs of new fluid etc. I can't recall who it was, but the suggestion was that I might not have done things the best way. Anyone??????????

[vex918]

The only way that works 100% of the time is to syringe the fluid from the calipers whilst the brake lever is held backonce you have fluid going into the reservoir stop and do the other side when both lines are full it should not take long to get pressure. once the pressure is there get a bungy cord ane wrap it around the handle bar and lever and leave it over night. in the morning you will have a really good brake.........works for me every time and i do this 3 or 4 times a year ( i like to strip and clean them that often)

[locksmithuk]

Originally Posted by two feathers

Can somebody please tell me the best way (The right way) to bleed a brake system? I posted comments before about having a bit too much travel through the lever than I would prefer, and went on to describe how I drained the old fluid and bled through a couple of reservoirs of new fluid etc. I can't recall who it was, but the suggestion was that I might not have done things the best way. Anyone??????????

There are several ways, all of which are right, but they come with varying degrees of frustrated cursing. The advice posted by Vex918 just below your post is sound. I would also reiterate the point about tying down your brake lever overnight - I used to leave the bike overnight & hope that air bubbles would naturally float up & out through the reservoir.... until I learned that the process is accelerated when you bring your squeezed brake lever into the equation. If you want to avoid trawling through this forum to get a good step-by-step process then go to trailtruck.co.uk, which has clear instructions & photos. Good luck.

[two feathers]

Thanks mate.
The lever tied back overnight sounds like my first step.
Thanks again to everybody.