as usual nothing has gone right for me,i have a 1992 cbr 1000f (non linked brake) so I did a full service running sweet as a nut , the rear pads weren't the best so I changed them bled etc working perfectly, front brakes had a little judder so I thought better to be safe than sorry so I stripped them down lightly greased slide points and pistons and seals,greased edges and rear of pads lightly,just as I have done on every bike ive ever had and now they just will not bleed at all??????? pistons will move freely round with fingers so they are not jammed,i have removed the pipe from cylinder and put my finger over the end to cause a vacuum and that works,it just doesn't seem as though there is the pressure to forcefully push the brake fluid out the bottom no matter how many times I have attempted to bleed,i opened the furthest away bleed nipple first and tried but at best got a trickle no matter what I did,ive checked the full system and there doesn't appear to be any air getting in or fluid leaking????? I think the fluid may be old but I would have still thought it would not effect any pressure?? I need to get the pistons to push in and out as they should then fresh fluid... im COMPLETLY PUZZLED,I HAVE DONE THIS A THOUSAND TIMES ON ALL MY OTHER BIKES BUT THIS 1 JUST DOESNT WANT TO PLAY!
PLEASE HELP

 

I'm no expert on brakes, but i had a similar problem to you on my old 95' cbr1000f with the linked brakes - lost all pressure on the rear brake - it was the proportional control valves for the linked brakes that was faulty.

If you are getting vacumn pressure from the master cylinder then i'm not sure what it could be apart from trying again with fresh fluid.

Hopefully someone with more knowledge than me may be able to offer better help.

fingers crossed you are able to get it sorted.

 

Sounds like your master cylinder piston seals are bad and or the master cylinders are
gunked up as well. What grease did you use ? Grease and brake fluids, lines and seals do not good neighbours make.

 

just out of intrest when you put your thumb over the pipe does the pedal stay hard or slowly depress (with no fluid leaking) as it may be your master cylinder seals letting fluid leak back through as sprok said

 

What the above 2 said. Thought the exact thing when I read this. Obviously there is some sort of blockage, build up etc. If you said a trickle and its not leaking anywhere then its just backing up your system. I would start at the banjo bolt. You can determine partially this way. Comes out easily from banjo then its obviously the calipers. Might as well just go ahead and buy a new thing of DOT 4. Its cheap, and in order to test whats wrong your going to have to lose fluid, old fluid I might add. You said you know how to bleed so yea. After that I would dismantle calipers. Check intake hose loactaed inside caliper on the bleed half. Check with compressed air. Remove pistons and examine your pathway. No offense but it is an old bike. A lot of times there isnt a need to seperate the calipers. They could have all sorts of build up in there. But yea if seals are shot, that fluid is just going to keep recycling. How is the tension when youre attempting vacum.

 

hi firstly thank you for the advice,its the front brake that's the problem,the rear one bled first time and is working spot on,ive looked everywhere and it looks like my bike should have the linked braking system but im presuming a previous owner has changed this as the front brake is on its own. at first I thought it could be a gravity feed system but no matter how high the resovouir is it does not leak,if I take the banjo joint of the resovouir so there is literaly no pipes connected at all,if I put my finger over the end and pump the brake it builds up pressure and squirts fluid past my finger,,,,the seals in the calipers all seem good , and when I say I greased up its been a smear rather than a huge lump lol,with everything connected as it should be,as it was before it failed there is no noticeable air/fluid leaks,just literaly not enough pressure to push the pistons out at all,,the only thing I can thing is a blockage in the pipe??????it looks to be the most unsophisticated brake setup I have ever seen,,it is literaly resovouir/handle,banjo to pipe,t piece to what looks like normal brake pipe,t piece then the 2 pipes to each caliper,no second cylinder nothing just pipe and calipers.
I thought really seing as the calipers do not leak and air isn't escaping they are working fine,with the handle/resovouir seaming to work when I put my finger over the end creating a seal I presumed that must work,the only obvious thing I can think of is the pipes are Donald ducked!!!!!!
SPENT A BLOODY DAY SCRATCHING MY HEAD WITH ALL THIS,AND UNFORTUNATLY THERE ISNT A COMPRESSOR AT MY MAMS,,IM GOING TO TRY AND JERRY RIG A WAY TO CHECK THE CALIPERS WITH SOME BLUTACK TO CREATE A SEAL AROUND WERE THE BANJO IS AND A FOOT PUMP.#
STRESSED TO DEATH LOL.
AGAIN THANKS FOR THE ADVICE GUYS

 

Are these the brakes on your bike? For some reason when I put in 92 1000F doesnt even come up. Oddly enough, It does for 93 and 91 but not 92?? Or do you have the 91 setup with the 2 pistons? It could be some mod of the original equipment or maybe there are diff brakes on it altogether....let us know.




91 Caliper

http://www.hondapartshouse.com/oempa...-brake-caliper

91 Master Cylinder

http://www.hondapartshouse.com/oempa...aster-cylinder
93 Master cylinder

1993 Honda CBR1000F A FRONT BRAKE MASTER CYLINDER | Babbitts Honda Parts House

93 Caliper

1993 Honda CBR1000F A FRONT BRAKE CALIPER | Babbitts Honda Parts House


When you take off that banjo at either of the front calipers, oil should be coming out of there. If it isnt and only starts coming out after applying the lever then to me that means an error at the master cylinder or in the line. Also, Im not sure about the linkage and what not, perhaps an owner can chime in there.

 

I had exactly the same problem yesterday after doing the exact same thing as you except I changed my pistons as well as seals.

Your 92 didn't have the linked brake system, yours is the k1fn. I have the k1fm basically the same bike.

To get my pistons and the bleeding done on my front brakes I cleaned all the grease off the pistons (the pistons need to be completely grease free) used new brake fluid to lubricated the pistons. I made sure there was as much brake fluid in the master cylinder then put the top on. I the opened the bleed nipple 1 turn and pumped the leaver about 10 times then closed the bleed nipple.

I then bled the brakes as normal. That worked for me yesterday.