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Discussion Starter #1
Hi all, I've had my 97 BB for years and I love it, just recently I have had a severe problem, twice now I've gone to apply the brakes (standard linked system) and the lever just pulls in with no resistance, luckily the rear worked. Ive also had the same with the rear. Any one else had this problem, I'm considering a de link !
 

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Not heard of such severe failure before. Have you changed anything (like the lever) recently?
If not sounds like the front master cylinder seal had failed or there is a buildup of crud that is causing your problems.
Are you on top of fluid changes?

Lets not talk about de-linking yet!
 

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I've had the bird for 9 years and never changed the fluid, I will do that asap. There is no problems when applying the brakes when cold, the problem has only arrison after a few miles riding, could a binding caliper be boiling the old fluid ?
 

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Surely front master problems would not cause the rear pedal to depress without resistance. I'll completely bleed the system with new fluid.
 

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If the secondary develops a seal leak yes it will. It will present itself as a pedal that goes away after a few days if the leak is minor. What it does is build up am air pocket in the big hardline running back to the rear caliper. The volume is so large neither master front or rear will show a level drop. When shows us when bleed it out. Then you get a big air pocket from nowhere. If that fluids been in there that long you would be better to pull everything apart. I'm betting your going to find a grey sludge (congealed) brake fluid that won't flush out. The only way to remove it is a teardown and swabbing.
 

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beestoys has (as expected) hit the nail on the head.

If the fluid hasn't been changed there will almost certainly be the grey/black sludge in the secondary cylinder and this can be difficult to move with normal bleeding procedures. Manually pumping the secondary cylinder push rod can work but this doesn't clear the gauze 'filter'.

When I change the fluid I normally don't let any air in (makes life easy) but since you have had a couple of failures I would go for a strip down. Seals can be replaced as you go, far cheaper than replacing the bike when you hit something.
 

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Discussion Starter #7
I'll take the secondary/front system off and see what I find, hopefully that'll cure it, then replace all fluid. Is the crud build up mainly around the secondary or anywhere in the system do you know ?
 

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Anywhere in the system. At all the cylinders Master, Slave, Secondary and brake calipers. About the only place that's safe is the lines.
 

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Discussion Starter #9
A strip down it is then, I suppose removal (or part removal) of the system before disassembly/cleaning would be the best approach. So it's the pumps and calipers that will more likely hold the sludge, I'll replace all the seals well it's apart. Thanks for the heads up, I'll keep you guys posted.
 

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A strip down it is then, I suppose removal (or part removal) of the system before disassembly/cleaning would be the best approach. So it's the pumps and calipers that will more likely hold the sludge, I'll replace all the seals well it's apart. Thanks for the heads up, I'll keep you guys posted.
Do you have skills and tools to do this brake overhaul? No disrespect but these brakes are more complicated than most and even qualified techs are often ripping hair out to get them right. De-link is the cowards’ way out. Get the stock system in proper order and it will outperform any de-linked set-up. Once set right just change the fluid (bleeding per factory instructions) every 18-24 months. You also might want to add a banjo bolt w/bleeder to the topmost brake line junction under seat - (see 98-2000 Honda VFR800) Good Luck! Great Bike!!
 

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I've had the bird for 9 years and never changed the fluid
You have solved the problem! The brake fluid has absorbed much moisture and now boils easily and fails to work as it should. Most brake fluids need to be changed every 2-3 years, especially if the bike isn't stored out of the weather.

The fluid will go 'off' even without riding the bike. Moisture gets in, but the BB does seem to be a well sealed system.

Still, I'd say 4years absolute max for hydraulic fluids and besides, regular changes keep the braking system nice and clean saving the need to replace seals etc.

(y)
 

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Still, I'd say 4years absolute max for hydraulic fluids and besides, regular changes keep the braking system nice and clean saving the need to replace seals etc.
FSM / handbook (if I remember correctly) says 2 years.....or perhaps that is just me but it serves me well. My 99 Bird is still on the original seals and pistons although I have replaced the rear caliper due to a non seal/piston issue. Lack of maintenance and use is what kills this stuff.
 

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Surely front master problems would not cause the rear pedal to depress without resistance. I'll completely bleed the system with new fluid.
Make sure you have a workshop manual, and bleed in the exact order it tells you, otherwise the system will not work properly.
 

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Discussion Starter #14
Do you have skills and tools to do this brake overhaul? No disrespect but these brakes are more complicated than most and even qualified techs are often ripping hair out to get them right. De-link is the cowards’ way out. Get the stock system in proper order and it will outperform any de-linked set-up. Once set right just change the fluid (bleeding per factory instructions) every 18-24 months. You also might want to add a banjo bolt w/bleeder to the topmost brake line junction under seat - (see 98-2000 Honda VFR800) Good Luck! Great Bike!!
I was a mechanic for many years and now an NHS technician, I've tools , manual and I'll probably have some time on my hands soon. Im just kicking myself for not changing tha fluid. Stay safe bros.
 
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