Topic: Installed Dual disc on CB500 used existing "T" to run both brake lines but....

[kwaggs27]

my question is, I ran the brake line from the master cylinder down to the port that was previously the pressure switch so I could just run the front ports down to both calipers but does it matter which port I run that master cylinder line to because for some reason my front brakes are dragging and make the bike VERY hard to roll. Even when I take it for a spin the pads don't retract into the caliper and the brake slows the bike down even without touching the lever. So Im wondering if I need to move that main line to the original location on the "T" to get the brakes to open up. Anyone have difficulties with this or is something wrong with my calipers possibly?

[Kong]

No, there is no sort of check valve in it.

[kwaggs27]

Kong if Im creating pressure from the master cylinder and it is not releasing the pressure after I release the lever where is that pressure supposed to go? It should return back to the master cylinder reservoir correct?

[DH]

Loosen up a bleeder valve (lever released) and note if there's any built up pressure.
If not, see if the calipers are still stuck. If no residual pressure at the caliper, and the wheel still won't roll, I'd think its a mechanical issue rather than hydraulic.

[kwaggs27]

Well Im pretty sure I bled my brakes wrong. I bled them like I would have a car. Pumped the lever, held down and then cracked the bleeder and let air bubbles out and then fluid until it was only fluid. Im not sure this is the accurate way to bleed a dual disc setup. I will try a different method tomorrow and hopefully be riding the bobber this weekend if its a little warmer!

[mjstone]

What are you using for a brake light switch?  I just used a double banjo bolt on mine.  Sounds to me like your bleeding it right.  DH's suggestion sounds more like it or maybe your master cylinder bleed holes are plugged.

MJ

[Kong]

You're bleeding it right.  There are two small holes in the bottom of your master cylinder's reservoir, one of them is probably blocked.

[kwaggs27]

The master cylinder has a switch built into it so I ran the wires up to that instead of the pressure switch. Kong is there any way to back pressure that reservoir in order to free up the clog or is disassembly the only method?

[Don R]

I saw a mechanic put a c clamp on the caliper to force fluid back through the return hole in the master cylinder to force it open.

[d3buttz]

are you using the brake pads fom the old bike the brake setup was on?   with the floating style caliper on our bikes the pads wear at an angle over time, and if the pads are from a left side and put on the right for the dual- it will not be flush on the rotor, it will be at an opposite angle of the wear now that it is 180 degrees.  it will drag much like the symptoms you described and it happened to me using old pads.   these pistons donot retract very much at all -lets .030" at most, and if the wear angle is more than that-youll have dragging pads.  i faced my old pads off with a lathe(wear a mask, nasty stuff)  or replace them with new ones that are perpendicular/parallell/flat?.  the dragging went away and the spongy ness that i felt on the lever was actually the pads compensating for the angled gap from the wear i described earlier.   good luck!

[plippo]

you can try loosening up the two big bolts that keep the 2 halves of the caliper together by 10/13 mm, then put a wood shim of 10/13 mm (or plastic) between the main pad and the disk.
then fasten the bolts. this normally pumps oil back to the reservoir enough to unclog the port...