jayninja
stranger
Reged: 23/07/2008
Posts: 3
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I have a braking problem and need help !
I recently purchased a 2002 Aprilia Tuono in a private sale. After the ride home and a few subsequent rides the brakes felt a little 'grabby' although still had good stopping power. An inspection of the Brembo calipers (non radial) revealed that at least one of the pistons in each caliper appeared to be seized. being fairly confident with bike maintenance I set about stripping the brakes, removing the pistons and all seals. I then cleaned up the pistons and calipers. I reassembled reusing the original seals as they seemed okay.
I thoroughly bled the system using a one way bleed valve and also left the lever tied to the bar overnight but the brakes still feel spongy. I've bled the system several times and there doesn't seem to be any air in the system, the brakes aren't awful but lack the 'bite' I'd expect or had before.
Does anyone have any tips/ideas. Do you think it might be because I didn't replace the seals ?
Any help would be much appreciated.
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chappers
Carpal \'Tunnel
Reged: 31/12/2006
Posts: 5115
Loc: Mind your own business
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I wouldn't advise re-using any seal they cost pence.
Have you bled the master cylinder? I changed the line on my bike earlier this week and had to bleed the MC via the banjo bolts as I was getting nowhere using bleed nipple on it once I got the juices flowing I bled the calipers then back up to the MC bleed nipple. I did tie the lever but there was no need. Another trick you might use is to unbolt the calipersand wedge the pads then bleed them holding them above the MC, there might be some air trapped in them.
If none of these work the strip them and replace the seals. Apart fron creating a seal the pistons rely on the elasticity of the seals to return them into place, actually I'd replace the seals anyway but then I'd never take a chance with my brakes.
I've tried all sorts of gizmos for bleeding my brakes and the best I've found is a length of pipe, bottle half full of fluid, care and patience.
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If you Believe you will achieve,init.
Dizzee Rascal 2008.
Edited by chappers (23/07/2008 20:59)
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chappers
Carpal \'Tunnel
Reged: 31/12/2006
Posts: 5115
Loc: Mind your own business
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Oh yea welcome mate. 
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If you Believe you will achieve,init.
Dizzee Rascal 2008.
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shinybusa
veteran
Reged: 08/01/2008
Posts: 1417
Loc: The wet place....
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Welcome fella.....and exactly what Chappers has said.. 
Never re - use seals..Not worth it as they do only cost a couple of pence, and you can't tell if a seal has deteriorated until it's too late, for a saving of a couple of pence , do you really want to put yourself and your bike down the road..... 
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EOD...EXPLOSIVE ORDNANCE DISPOSAL....
Is a science of vague assumptions, based on debatable figures, derived from inconclusive experiments performed by people of doubtful mental capability, with instruments of problematic accuracy....
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jayninja
stranger
Reged: 23/07/2008
Posts: 3
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Thanks guys, appreciate the advice. For some reason I was under the impression the seals might set me back silly money that's why I re-sued them.
I shall order a new set and try again - Will let you know how I get on.
Cheers,
J
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BigHam
old hand
Reged: 12/11/2006
Posts: 1096
Loc: Letchworth, UK
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Get new seals, but you were using a new sealed bottle of brake fluid too? Brake fluid absorbs water from the air if it's left lying around unsealed and water is compressable, giving the spongey feeling you complained of.
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http://www.myspace.com/big_ham_1988
Where there's a will and Gaffa Tape there's a way!
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FastBikerBoy
old hand
Reged: 08/11/2006
Posts: 1124
Loc: Norfolk surrounded by Yanks
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Quote:
Thanks guys, appreciate the advice. For some reason I was under the impression the seals might set me back silly money that's why I re-sued them.
I shall order a new set and try again - Will let you know how I get on.
Cheers,
J
Doesn't matter how much silly money they are it won't be as silly as laying in a hospital bed or laying underground.
Two things you should NEVER skimp on are brakes and tyres.
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Cheers
FBB
Remember kids don't try this at home
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jayninja
stranger
Reged: 23/07/2008
Posts: 3
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Here's an interesting development, I called my local Aprilia dealer and they told me that Aprilia or Brembo don't actually supply a seal kit for their brakes ! I haven't called Aprilia direct yet, but my dealer said that I might need to send the calipers to aprilia for them to service them.
This is my first experience of Italian machinery - I miss my Honda !
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monkiboi
old hand
Reged: 11/11/2006
Posts: 825
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You could always try someone like M and P, Busters or Demon Tweeks. They often do lots of things like seal kits and bearings. If they're Brembos, DT might be the best option, not always the cheapest but certainly one of the most helpful with good speedy delivery.
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Only ride as fast as your guardian angel can fly!
I've been wondering, can a tortoise swim?
Not according to 118118!! (can someone lend me a tortoise to see if they're right?)
Edited by monkiboi (24/07/2008 20:59)
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chappers
Carpal \'Tunnel
Reged: 31/12/2006
Posts: 5115
Loc: Mind your own business
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I think this is a job for morepowers advice.
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If you Believe you will achieve,init.
Dizzee Rascal 2008.
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BigHam
old hand
Reged: 12/11/2006
Posts: 1096
Loc: Letchworth, UK
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If you have the 1 pad per piston calipers on your Tuono that look like this:
Then no they don't run dust seals for less friction, but they need cleaning more often.
I would have thought they still had some sort of seal to keep the fluid in though.
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http://www.myspace.com/big_ham_1988
Where there's a will and Gaffa Tape there's a way!
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