HELP ! CBR 600F 1990 L Front Brakes Like Sponge & brown under pant moments !!!

[shiftyblake]

Hi,
Can anybody help, I have new front brake pads 1,000 miles ago, bled fluid again recently, and I have to try and snap the brake lever to stop quickly. I used to ride new Honda's and could stop on a six pence. Do I need some form of upgrade? Or is this what you get on older bikes??
Any help appreciated, otherwise I will just have to keep changing my under pants after my ride outs !

Shifty

[Swanny]

Did you completely renew the brake fluid??

[shiftyblake]

Hi, yes it had new fluid.

[Swanny]

Does it get better if you pump the brakes?

[napalm]

There's a few things to check...
Was the fluid from a new sealed bottle? Was it the right fluid (dot4)?
Was it bled correctly? Are you sure all the air is out on both sides?
Is the reservoir over or under filled? Overfilled can cause problems as well..
Do you have a leak in the system? Check at the banjo bolts, master cylinder, bleed valves, pistons and check all lines for cracks or deterioration.
Were the brake pistons cleaned and checked when the pads were changed? something might be seized or binding.
You may have got dirt in the system causing a blockage affecting the hydraulics.
Have the brake lines ever been changed? I probably would have expected so on a bike of that age.
Are the discs still in spec?
Have the brakes got progressively worse since the pad change?

On the flip side, my 98 blade brakes are not as strong as my 11 plate cbr6 brakes were, older technology I guess, I( think) fewer pistons so less braking force. Still on a 600f, even that old I would expect the brakes to work!

[Scotty]

What sort of pads did you fit?

[shiftyblake]

Thank-you everybody, decided to replace the dot4. Full of crap and so was the reservoir that I have cleaned out. The bike wont bleed now, but leaving the fluid to settle for a couple of hours. If this doesn't work I will replace the hoses with braided hoses.

[napalm]

Sounds like a good approach. Make sure you flush the system well with dot 4 before priming it, its likely you have crap in the master cylinder and calipers.
Might be worth making a mess and removing the old hoses without draining the system. It may be messy but IMO better than forcing gunk through into your calipers by draining through the bleed nipples. If you do this, protect your bike and paintwork well! Disclaimer, I'm not a mechanic, just makes sense to me. Others on here feel free to call me out as talking horse****! :-)

[napalm]

Oooh, censorship! :-)

[Swanny]

Oooh, censorship! :-)

Oh that's not good

[napalm]

Especially if you live in s****horpe!

[napalm]

Yep! Censorship alright!!! :-)

[napalm]

@shiftyblake. Fitted my braideds today and found I had to directly bleed the top banjos as they were the highest point of the system.

Cover under the master cylinder with copious rags to protect your bike.
Put pressure on lever and quickly crack open the top banjos and close again while keeping gentle pressure on the lever.
Just crack it open enough to let out the trapped air, it should bubble and fizz out the gaps, or squirt a bit if you open too much.
As long as you close it before the fluid stops coming out you're all good.

My brakes are now vicious!

Good luck!

[Swanny]

Censorship is **** and this is really strong, can't even say poo :confused: