CB700SC Brake Troubles

[jperecko]

New to the forum... I have done a lot of work on my hawk and now one of the simplest systems on it has me stumped.

My front brakes are soft. There is still good material on the pads and the discs are clean. There are no visable leaks anywhere. When I pull the brake lever, it depreses all the way to the grip and does not have a firm stop. I have bled the system several times. I figured that the problem was with the master cylcinder seals leaking so I pulled one off a ninja which has a good system and it is a little better but still very soft and letting the lever hit the grip. The only other option I see is that the lines are swelling and causing the soft braking. Is there any other potential problem? Are there any seals in the calipers that can go without visible leaking?
Thanks

[gammer]

I'd check the lines for swelling.

If there are no visible leaks, the lines are air bubble free, and you've replaced the MC with a known good one, then there can't be too much left to check.
Are the calipers working 100% / not seized?

[jperecko]

both the discs got warm from a little bit of testing... so I do not think anythign is stuck in the calipers...
Swelling, will it be noticable? I do not see any cracks or significant damage on the lines
How would the swelling look?

[86cb700sc]

Swelling may not be visible. On the other hand, I'd replace the hoses just as a matter of course - they are over 20 years old now - with braided stainless steel hoses. That and a master cylinder rebuild should resolve the problem.

[jperecko]

Any good sources for the steel lines? I plan to get some for my car too.

[mikeinvaf16]

i had the same problem with mine and it was the brake lines. they are no longer available because the bike is so old (mine is an 85) so i ordered galfer brake lines. the package comes with 2 lines,1 for each side. the 2 lines hook up to the m/c with the supplied longer banjo bolt. it made all the difference!! i have excellent brakes now. i have also ordered the clutch line cause its getting soft also. i ordered the kits from sum of all parts at a really good price.
mike