Dual disc troubles

[Coulisnosaj]

I have a CB750k3 with dual CB500 rotors and calipers, GL1000 master cylinder, and SB lines. I can’t seem to get the squishiness out to the lever, to save my life.  I bled the brakes several times; crack the joints to make sure there wasn’t trapped air, and then re-bled again and again, that didn’t seem to help.

I thought maybe the original CB750 splitter/divider AKA “T” wasn’t distributing the brake fluid evenly. I disconnection one of the lines and that seem to work much better, there was more firmness in the lever with only one brake. So I bought a GL1000 T, thinking that would be the fix (since it was designed with dual brakes in mind ) after installing and bleeding again and again, it was even worst than the original.  

So before I drop some more cash on a brand new master cylinder, I’d like someone to tell me if I’m missing something or is the master cylinder the real culprit in this whole debacle.  All the best and thanks in advance!

[Coulisnosaj]

BTW - there brand new Steel braided (SB) lines...Question, can the lines be too long?

[gonebiking-2]

Dont think the lines are too long. Perhaps its the wrong master cylinder. Try the original master cylinder for that era bike and you might save yorself a great deal of hassles and a headache to boot

[Rick V]

The length of the lines wont have any affect as long as they are bled properly. One thing you may be overlooking could be the adjustment of the calipers.If the adjusters are too loose it could cause the pistons in the calipers to travel too far before the pads make contact with the rotors.Use a .003 inch feeler gauge between the inner pad and the rotor and adjust the screws on the pivot plate until the feeler gauge just slides out. The GL master cylinder should have enough flow to operate properly as it was used on a twin disk setup.

[gonebiking-2]

Well said Rick V- I knew there was something I had forgotten aboout. Fortunately I havent had a problem like that ever, but had read abotu it n the workshop manual. So hopefully  that might just solve his problem. Knowledge is power I vote for you to become the next USA President :))

[InTheWind]

I'm not sure how you bled the brakes but the way I prefer is by hooking up a line to the bleed nut and putting the other end in a jar of brake fluid and pumping the handle. Be sure to keep your reservior full and that should help. Another trick for after that is to fill your reservior and use a zip tie and tie the lever back, like your pulling on it, and let it set overnight. I have done this several times and if your system is in good shape the next day your brakes should be good to go with no squish.

[gonebiking-2]

Just a thought - one doesnt get shot for thinking - when you bleed the front brakes, do you remember to screw the bleed valve back in, so that you are not sucking air in ??? You would be surprised the number of people I have come across in my lifetime that forget to tighten the bleed valve and wonder why they still have no brakes !  Just a thought.

[buttcan-2]

Hey, One of the guys on hondachopper.com had the same issue recently. I don't remember exactly what he did, but I think it was something like letting the system open over night so as to let the air rise without being under pressure. If I find it I'll post it here. N.