Triumphrat

Mr*Beaver

So I had a funny one today whilst riding through heavy traffic for about 6kms. It was stop start and tight so I rode the read brake for a bit, however after a while it stopped working! Worth mentioning it was also around 34 degrees out.

If I pressed the brake I could push the lever all the way down with no resistance at all.

After that I stopped filtering and just used my front brake, after another 20 min the rear brake comes back to life and works again.

Whats the deal? A 2008 Bonneville doesn't have electronic brakes?

plodalong

Most likely moisture of possilby air in the brake fluid. Moisture (water) is absorbed into the fluid and lowers the boiling point of the fluid creating vapour bubbles which are compressible and either gives more lever movement or stop the brakes working completely when they get hot. Time for fluid replacement, Ment to be replaced every couple of years.

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07 thrux,breathe,Dna airfilter,airbox X restrictor,135 mains,1 shim,tp +3 ignitor,yss emulators,hp springs, Bitubo shocks,pingle steering damper,D9 layflat,3" rise clipons,corbin seat, tt350 taillight,alloy indicators.shorai battery,Changes daily

norton74

You may have had the rear master cylinder piston hang up due to corrosion. Probably not the case; but, it's what happened to my '79 Bonneville.

As a precaution, I would flush the brake fluid and bleed the brakes both front and rear.

Hypurone

You are on the right track. The M/C probably experienced a "by-pass" due to an internal cup sealing or check valve issue. Hence the intermittent workings... Flushing can help if the system's fluid is degraded, contaminated or has moisture etc. But once it happens it usually only gets worse and happens more often. I would cut to the chase and replace the M/C flush the fluid and call it a day...

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Chuck
'10 Thruxton 944cc - In the Faster Color
"Ridin' It Like I Stole It"

PAAS

Sounds like boiling brake fluid to me too. Has it ever been changed? As Plodalong said, it should be changed every 2 years as a matter of course irrespective of mileage. Try the simple (and cheap) stuff first, before making it more complicated than it probably is.

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Paul.

Herts. UK
Aubergine & White 05 T100 (865cc) with numerous mods.
(Previously Ducati Monster S4 and several UJMs)

Demonic

Yup, spend a couple quid (dollars, whatever) on fluid, rather than hundreds (or whatever they cost) on new parts...

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If knowledge can create problems, it is not through ignorance that we can solve them.
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bonza

with the amount of rain and humidity they get in Brisbane I'm betting moisture in the brake fluid as plodalong says. change the fluid on both brakes

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2007 B&W T100.
AI & Snorkel gone, Dom Tourers, 40/120/1 shim 3 turns, TTP stage one, Dart screen, Pingel fuel valve, Monza gas cap, Avon Roadriders, Triumph fabric saddle bags sometimes

Mr*Beaver

I'm gona roll with brake fluid as first course. I didn't get any service history with the bike, although I know some things have been done, this isn't one of them.

It's just annoying as I was planning on doing it along with the pads in a couple of weeks, but haven't sourced the pads... anyone know where I can get some pads from quickly without paying premium prices?

RICHW

On a 2008 I would also check your rear pads - they tend to wear out.

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• 2∞6 B0NNEVILLE T1∞ •
my garage pics and specs

please keep your distance

Mr*Beaver

rear pads are *fine* at the mo - this isn't the issue in this case.