squishy brakes :(

Hi all,

Not my first rodeo with brakes so I'm not really sure what's going on here. I have a kz750e dual front discs. Lever is spongy, like goes all the way to the grip. IF you pump it a couple times quickly it builds great pressure. I rebuilt the master cylinder and pumped fresh fluid through but still the same issue. I have all new fluid in the lines and i spent a good 45 minutes bleeding them and I am long past air coming out of the lines.

One thought I had was about the lines themselves. I have two stainless steel lines but both bolt to the master cylinder instead of the "usual" setup you see with a single line going to a splitter on the triple clamp. So each caliper has a line running from the master cylinder to the caliper. Not sure if having these two long lines is the issue or what.

Any help would be appreciated. Thanks!

Pump up the brakes and then strap the lever against the bar and leave it. The constant pressure in the system will cause the caliper pistons to creep closer to the discs, which often times eliminates the spongy feel. Needless to say though you should extract the caliper pistons from the caliper body and clean out all the grunge first. Pitting on the pistons is very common so be prepared to replace the pistons if you find any.

cool, thank you, i will give that a shot

I just finished my brakes, replaced pistons, seals, master cylinder, brake lines same results spongy lever. Fluid clear, tried all different methods same results until I pumped up front brake lever, while holding pumped up lever, zipped tied lever to the bars set over 24 hr period remove zipped tied much better lever pressure. worked for me,

I just put brand new braided s/s lines on mine - all 3 with stock splitter. The were spongy before but now solid as a rock. I use a fluid pump and pump it in through the bleed nipples. Then just do a quick bleed as normal. I find it the quickest way to get it done. Another Z750E brother!

I recently put a Shindy MC on my 1000 and rebuilt the calipers.
I had this problem too.. I pulled the calipers and pushed the piston all the way in very slowly. one at a time as to not overflow the MC.
this did the trick.. I think i had air some where high up and by doing this it pushed it out the MC.

Rustyhama, your procedure interests me, I'm going to try the less invasive stuff listed here first, then go with this if those don't work