Bleeding brakes (dry)

[wilf]

G'day all,

Just got meself some HEL braided lines. Obviously will need to drain fluid then fill and bleed system. I have read a bit about this and some people say they have trouble getting a firm lever using the conventional 'top to bottom' method after full drain. Have read around that 'Back bleeding' is the way to go. Anyone have experience with this? Im going to get the syringe tomorrow, it seems straight forward enough, but any pointers greatly appreciated!

thanks

[csgup1]

wouldnt have a clue on the bleeding but where did you get the lines from and how much

cheers!

[MrWasabi]

Rob and I fitted lines on the old 6 we drained the system dry, pulled the caliper and master cylinder apart and gave everything a good overhaul.
Filling it was time consuming, but it wasn't tricky, its a lot easier with 2 people for sure.

Guess filling it from the bottom up you would need a pretty big syringe to make sure you fill the calipers and both hoses.

[Glen]

Fill the reservoir, open the nipple on the caliper, get a long piece of clear tube and suck it through until you see the fluid come through the hose. Then just bleed it as normal. Suck it through both sides before you start bleedding though. It'll take you about 30 mins.

If you don't like the ever pleasant taste of brake fluid, get a big syringe and draw it through

[wilf]

wouldnt have a clue on the bleeding but where did you get the lines from and how much

cheers!

I got them from here: clicky

...Guess filling it from the bottom up you would need a pretty big syringe to make sure you fill the calipers and both hoses.

Yea its not like those you get a flu shot etc its much larger...

Fill the reservoir, open the nipple on the caliper, get a long piece of clear tube and suck it through until you see the fluid come through the hose. Then just bleed it as normal. Suck it through both sides before you start bleedding though. It'll take you about 30 mins.

If you don't like the ever pleasant taste of brake fluid, get a big syringe and draw it through

Hey Glen, I'm aware I can do it this way...I've bled them this way before...just curious as to back bleeding. I read if you go from bottom up it eliminates air pockets and bubbles much more effectively as air in the fluid will rise to the top. So if you got from bottom up you are not 'fighting' against this. Supposedly once the fluid reaches the m/c you wouldn't even need to pump levers or anything because there should not be any air in the lines. Should take 10 mins...*shrugs* ... I'll give it a go and if it doesnt work out I'll do the conventional bleed. Just wanted to see if anyone has back-bled before and how it went...

[Gosling1]

filling the lines from the bottom, may work OK - I have never tried this method. If you want to build up lever pressure quickly, I generally bleed from the m/c banjo bolt. This is much quicker than bleeding with the nipples on the calipers. Just pump up the lever, hold it in, 'crack' the m/c banjo bolt open for a second then close, and repeat until you have good pressure. You will need to wrap a big rag around the m/c, so that any fluid which escapes, just gets soaked up by the rag.

I have been bleeding brakes this way for decades - its quick and effective.

[oldman]

Heres my worthless drunken 2 cents worth of bullshit. You need to have two people, (one should be drunk and the other one semi-sober). Fill the M/C and replace the cap, have the drunk one pump the shit out of the brake pedal or lever and hold it down, open the bleeder on one of the calipers while the lever is held down, (make sure the drunk does not release the lever it until you have tightened the bleeder valve), repeat until no more air is coming out of either bleeder valve and you have a solid pedal or lever, CHECK THE FLUID OFTEN AS IF IT GOES DRY YOU WILL HAVE TO START OVER. BRAKE FLUID WILL DISOLVE PAINT AND MAKE THE BRAKES VERY GRABBY IF IT GETS ON THE PADS, SO ATTACH A HOSE TO THE NIPPLE AND HAVE IT DRAIN INTO A CAN. The secret is how hard and how long you pump the lever eight to ten times usually works. This has always worked for me since the late 50's. Good luck.

[Gosling1]

OLdman - thanks for that. That is the normal way that most people bleed brakes (maybe except for the drunken bit ), because the bleed nipples are down low on the caliper. It is also really time consuming and uses a lot of brake fluid to achieve any sort of 1/2 decent result, and it requires 2 people.

There is a good reason it takes a long time and lots of pumping to get decent brake pressure doing it this way - its because you are attempting to push air 'down', inside a fluid.

Air naturally rises when it is trapped inside a fluid, not falls. Cracking the m/c banjo at the top, allows any trapped air to rise *very quickly*, because it is travelling in its natural direction. You don't need 2 people to bleed the brakes, there is much less wasted brake fluid, and my experience is that good solid lever pressure will be obtained within a minute or 2 using this method (often less).

There is only 1 real issue that puts most people off doing it this way - and that is the possibility of having brake fluid spill on body panels or paintwork. To stop this happening, just use plenty of rag (ie old towel) around the area of the m/c banjo. This will prevent any splashing of brake fluid onto painted surfaces. In any case, because solid lever pressure will ob obtained really quickly (unlike the age-old method of bleeding at the caliper nipples, one each side...), the amount of fluid loss is minimal anyway.

If you have never tried this method, you may want to give it a go sometime. Really got nothing to lose ??

I stopped bleeding bike brakes the old way back in the early 80's, because it takes forever, you need 2 people, lots of fluid gets wasted, its messy as buggery etc etc. By and large its a total pain in the ass.

[waynemorgan]

When I recently rebuilt my calliper I did a back bleed. Drained all the old fluid out of the line so it was completely empty. Put a tube on the syringe then filled the syringe and flicked out any air bubbles in it. Fitted tube to open bleed nipple and used a zip tie to secure it. Pushed the fluid in until the res was 3/4 full. tightened bleed nipple and removed the tube. Initial feel at the lever felt like some air in the system - solution was to pump the lever 50-75 times - you'll see the air bubbles come out. Once they stop you should have a hard lever - seal up and ride carefully

This way was really easy for me as I did it by myself. Worked well - no spilt fluid etc.

[wilf]

Thanks everyone for the responses...I shall report back on how it all goes once i get around to doing it.

[oldman]

Gosling1. I'm always open for a better method of doing anything. Thanks for the input I will try it out very soon is it's time for a fluid change on my Z. I drop you a note and let you know what I think. Thanks again.

[wilf]

Just did this with new lines.

I did back bled the system, using syringe and all. For a first timer It wasn't too difficult at all but still requires a bit of patience. First of all I drained all the fluid using the syringe by sucking up all fluid in MC then caliper nipples. Carefully removed all the old lines making sure no fluid dripped onto anything. Installed the new lines. Using the same old fluid, I got my syringe and put fluid through the system from the nipple. I can hear when the fluid reaches the MC and the air bubbles coming though. I did this for both sides till MC was near full.

The lever was sloppy so I went and did conventional bleeding, luckily I have a one-man bleeding thing (Has a one-way valve) so I dont have to keep opening and shutting the nipple. I kept doing this, pouring the old fluid back into the MC (so theres no wastage I only had 1/2 bottle of new fluid) After about 6 MC worth of bleeding I had virtually no bubbles.

This is where my newbness shows up...

To my shock horror the lever went all the way back. no pressure at all. and so I kept on bleeding it for about 1/2 hour. Finally I gave up. Went to the other side and within the first 2 pumps of the lever, it firmed up. So all I had to do was do this side lol. Oh well. This side was done in 2 mins. I then did a normal fluid change bleed with the new fluid, so I didn't end up wasting any new fluid.

Lever is now firmer then ever before, and should have next to no fade watsoever. Looking forward to tracky days

I'll probably bleed it again after another 200kms or so, just to make sure all bubbles they may have been 'dislodged' comes out.

Pretty straight forward, all in all I reckon if I had to do it again, from starting the back bleeding to having no more air bubbles, for a dry system, would take about half an hour?

EDIT:
I also just wanted to give Slipstream Performance https://www.slipstreamperformance.com.au/store/index.php a little plug as well. Apparently they make the braided lines to order and the ones I got fitted perfectly + are of GREAT quality. I ordered and paid on Thursday, they let me know it was dispatched on Friday, and I got them today at Midday. Got tracking number as well, and kept up to date via emails. That is super quick and for once I got the right parts unlike some other internet experiences I have had.