Bleeding question ....as in changing brake lines.

[eyore]

I am changing the Wunderlich top yoke and straight bars to put back the originals on Humbug.
The Wunderlich kit attaches the original brake lines into the bottom of the yoke and there are short upper brake lines that extend above the yoke to give the required length.
My question is , if I detach the original brake lines to re attach them will I Have problems with air in the lines that cant be sorted by refilling fluid from the calipers upwards to force the air up. I don't think it will affect the abs system in any way, but can anyone confirm that?
Also whats the story with bleeding the clutch?
Thanks.

[herrman]

Hi,
I don't think its as easy as that, Bleeding the brakes on an ABS system was a total nightmare when I tried it--Took me over a week to get decent feel back at the lever. I'm not saying it cannot be done but I would recommend plenty of internet searching first. Do you really need to put the shorter lines back on??

Regards Peter.

[eyore]

Hi,
I don't think its as easy as that, Bleeding the brakes on an ABS system was a total nightmare when I tried it--Took me over a week to get decent feel back at the lever. I'm not saying it cannot be done but I would recommend plenty of internet searching first. Do you really need to put the shorter lines back on??

Regards Peter.

Hmmm, I was afraid that was the case. Unfortunately I do need to change the upper pipe as the actual yoke is drilled with fluid passing through it, the original pipe is attached under the yoke and the new short extension is attached to the top of the yoke.

[Corvus]

Hi

Does the swap back just involve reconnecting the pipe which is presently connected to the underside of the yoke, back directly onto the master cylinder? If so, as long as the fluid below that level is left alone while you do the swap, then the only air that will be introduced will be the couple of inches into the master cylinder.

If I've understood that right, then it shouldn't take long to bleed that small amount out. Maybe careful positioning of the bike/bars will be needed to ensure the trapped air can rise and find its way into the reservoir. Maybe even slacken the master cyl clamps and suspending it at an appropriate angle to be absolutely sure air can rise up and out. Squeezing the lever to compress the fluid seems to encourage the air out by displacing it from nooks and crannies, and maybe encouraging smaller bubbles to form into larger ones and therefore rise quicker. Just remember that whilst the lever is squeezed air can't get into the reservoir, but it will do once the lever is released. Allow a bit of time and maybe several on/off squeezes of the lever. The hole from reservoir to cylinder is usually tiny.

Hope I've understood you correctly.

Cheers

[nab 301]

?
Also whats the story with bleeding the clutch?
Thanks.

Not that I have a 12S , the 11S has the extension to the slave cylinder with a spring loaded ball , looking at the parts diagram this isn't on the 12S S. I don't know how accessible the bleed nipple is on the back of the gearbox though.

[eyore]

Hi

Does the swap back just involve reconnecting the pipe which is presently connected to the underside of the yoke, back directly onto the master cylinder? If so, as long as the fluid below that level is left alone while you do the swap, then the only air that will be introduced will be the couple of inches into the master cylinder.

If I've understood that right, then it shouldn't take long to bleed that small amount out. Maybe careful positioning of the bike/bars will be needed to ensure the trapped air can rise and find its way into the reservoir. Maybe even slacken the master cyl clamps and suspending it at an appropriate angle to be absolutely sure air can rise up and out. Squeezing the lever to compress the fluid seems to encourage the air out by displacing it from nooks and crannies, and maybe encouraging smaller bubbles to form into larger ones and therefore rise quicker. Just remember that whilst the lever is squeezed air can't get into the reservoir, but it will do once the lever is released. Allow a bit of time and maybe several on/off squeezes of the lever. The hole from reservoir to cylinder is usually tiny.

Hope I've understood you correctly.

Cheers

Absolutely, that's the situation. You have just cheered me up. I think we will try it next week.