Draining front brake lines

[barelycompetent]

Hey all, I just read the tech section article on bleeding the front brakes, and that was an excellent article and well written, makes me feel somewhat competent to tackle that problem. I have to replace the upper brake line as mine sprung a leak on me. I want to just go ahead and drain out all of the old fluid and start fresh when my replacement parts come in, but the article never mentioned how to do that. Do I just put a tube on the bleeder nipple and crack it open and let it drain, or is there something else I have to do at the same time? Most of the fluid is out of the reservoir and and the upper line already. I was planning on just removing the bottom banjo bolt from the upper line and letting the remainder of the fluid drain out before replacing that part of the line, but that would leave fluid in the bottom brake line so there has to be a way to get that out first. The Haynes manual is not clear at all on how to do this. Any help, suggestions, tricks or advice is greatly appreciated. Once the old fluid is out, and the parts are in I plan on following the bleeder article in the tech section as I tackle that problem. Thanks all.

 

[FrkyMnky]

Use the banjo on the caliper and just let the line hang. Be sure to crack either a bleeder or banjo up top so the brake fluid can drain. If you want to drain the caliper, you can use the bleeder or remove the caliper and turn it up and drain it from the banjo.

 

[barelycompetent]

That sounds good. I think I will undo the banjo on the caliper as you suggested, cause by my reckoning if I drain the line, then fill it with fresh fluid, go thru the bleeding procedure, the remainder of the old fluid should be pushed out of the caliper and replaced with new stuff while bleeding the brakes. That sound about right? Once I drain the lines I can replace my upper brake line, tighten all the banjo bolts and proceed with bleeding. Sounds easy enough lol but this will be my first time bleeding brakes so fingers crossed!

 

[XSLeo]

If your upper line is so rotted as to spring a leak, don't you think the lower is bad too?
I would change both lines. Braided stainless steel is a very good upgrade over the stock rubber lines, gives better braking. Either two short lines or one longer single line.
If you are trying to maintain a stock look on the lines cover with black heat shrink tubing. This looks almost stock and adds further protection from the sun or abrasion.
Leo

 

[barelycompetent]

Good advice Leo. I dont think the upper line was rotted, it looks like it was pinched or rubbing on the headlight assembly. Probably my fault when I changed the bars to clubmans, I rerouted the line behind the bucket and put too much stress on it. I will give the bottom line a once over though just to be sure. Gotta make sure I dont do the same thing with the new line as well so careful routing and planning for sure.

 

[jd750ace]

Plus one on replacing the lines. I chunked my stock lines and master cylinder and have an 11mm Brembo master and a one piece Galfer SS line. Braking is top notch, and overwhelms the forks, which I have not gone through yet.

 

[5twins]

Most of us dump the two lines and go with one long stainless replacement. You can get them off eBay in any length and color for about $35. You also get a choice for the angle of the end fitting. The top fitting can be straight but you need some angle in the lower one to clear the caliper .....

 

[XSLeo]

Rubber lines tend to rot from the inside out. Can't really see the damage. If you look at the lines you might find a plastic ring around it. This ring has a manufactured date on it. I bet your lines are as old as your bike.
I wouldn't risk a brake failure just to save a few bucks. Most brake failures occur at very inopportune times.
Leo

 

[barelycompetent]

Very sound advice indeed. Ok so if I ditch the dual line set up, is there anything special I need to add or do for a single line? What is the purpose of the dual lines on the stock bike? Is the banjo bolt connection behind the triple trees really necessary, or is it just that easy as running one single replacement line? Thanks for the answers you guys havent steered me wrong yet!

 

[XSLeo]

They used the junction on the lower tree to make it easy to add a second line to run a dual disc set up. Some years used the junction block to add a pressure switch to activate the brake light when the front brake was used.
If your bike was this way adding a banjo bolt brake light switch is easy. Just replace the banjo bolt at the M/C and wire it to the leads that hooked to the junction switch.
Leo

 

[5twins]

Some models came with dual discs on the front. That junction block was there to split off of and run the second line to the second disc. It's totally unneeded for a single disc set-up. I fabbed up a "guide" for my new single line to bolt in its place .....

 

[barelycompetent]

My bike is the single disc up front, and it does have a break light switch on it. So it looks like stainless it is! Thanks for the tips and advice, now I wait for the parts lol.

 

[5twins]

Due to your lower clubman bars, you are probably going to need a line a few inches shorter than the stock set-up. An easy way to "measure" for what you need is to get about a 4' long length of house wiring, pull one of the solid copper wires out of it, and use that as a template for routing and then measuring. Stick one end up through behind your headlight and wrap the end around the banjo fitting on the MC. Route the other end down to the caliper the way you want it and mark the wire. Pull it out, straighten, and measure.