hi there, my 955i speed triple has spongy brake lever. brakes work fine but lever comes back about half way to handlebar. have bled a few times , got braided hoses, new pads, new fluid. the seals in the calipers were changed 2 years ago, theres no leaks. its 23 years old. do you think its worth changing the piston and seals in the master cylinder. thanks
In a word YES! The master cylinder seals could be around 20 years old and it will be well worth changing them. Whilst there is no leak from the master cylinder fluid may well be getting past the main seal but not the secondary seal.
cheers ,thanks for the advice . i'll order parts tomorrow and give it a go. i thought they might need doing as you say seals do tend to wear after 20 odd years. thanks again
How many miles has it done ? I had a 1998 Triumph Sprint Executive with 91,000 km , brake's were spongy , took the calipers off the fork legs , good strip down and clean , rubber grease , rebuilt and a good bleeding , they came up better than new ! There was Soo Much dirt , the calipers were almost seized !!! Hence the spongy feel at the master cylinder , it wasn't moving anything !! Brake's were working , but only because a single piston in each caliper was Moving. Only one pad was doing all the braking/wearing ! New pads all round and sorted ! Was still good 16,000 km 14 months later .... !
I did this exact same job anout 18 months ago on my exact(ish) same Speed Triple 2002. I ended up (myself) doing a complete caliper stripdown, clean, and rebuild... Including splitting the caliper(s) into their respective halves. I PROMISE that isn't as hard as it sounds, I took the opportunity to replace seals and positions, and all hardware to SS... What surprised me was in all the finer capillaries within the caliper, as I was cleaning, these were all lined with a kind of like waxy muck. I had previously bled the brakes, and this stuff would never have washed out in that way...I used inter-dental brushes to clean them out. *edit - my point being, I think this waxy stuff is what was making the brakes spongy! Cleaning all that gunk out, and then using all the other advice from here, a good bleed, keeping the brake levers held on overnight etc....and my 23 yr old brakes were sharp as ever! There's a useful thread on here which is this Good luck, keep us posted!
