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Soft Front Brake - Honda Spada

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Captain115, Oct 31, 2012.

  1. Hi everyone,

    Now I'd like to start off by saying 1) yes I have searched and 2) this is not a super critical problem, just something which I would like to gather suggestions from more experienced people.

    Ok so it's my friend's Honda Spada he bought about a month ago. I ride it a couple of times a week if it's free and I don't feel like using my bike; it's great fun to power around and corner on, plus the V-twin sounds beautiful at high revs.

    But the front and rear brakes are annoying me a bit, they simply don't seem to work very well, particularly the front.

    Rear Brake: I've replaced the fluid (was a funky colour) and bled it twice to double check there was no air in the system. Pads have plenty of meat on them and the pedal is at the right height. It just seems to not really do much and then will grab suddenly. Doesn't seem to have a linear response. This doesn't really matter that much, as it works ok when needed but I was wondering if this is normal and/or is it just my technique?

    Front Brake: Ah now this is a problem. The front lever is very, very soft. I have already flushed and replaced the fluid, checked the pad thickness, bled the system about 5 times for air (thought it might be a leak somewhere and air could be getting in, but none came out each time I re bled it). The lever is adjustable, but even with it set out as far as possible I can get it to touch the throttle grip. Note that the front will still stop you ok, just seems the lever is super soft. Particularly obviously when standing side by side with my bike and grabbing the levers on each bike.

    So any ideas? Maybe the 23 year old rubber brake lines are buggered and allow a lot of expansion?



    Cheers,

    John
     
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  2. Have you checked the pad and rotor thicknesses?
     
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  3. Yep, both front and rear pads and rotors are above spec.
     
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  4. Sounds like new braided lines are the go.
     
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  5. Braided might help slightly, but seems unlikely the existing lines would swell so much as to cause the problems described (at least not without an obvious bulge at some point in the line).

    I'd be inclined to think the problem's more likely to be with the seal in the master cylinder, ie it's letting fluid slip past when the brake is applied reducing the force that can be applied to the pads. Swelling of the pistons seals in the caliper could also be a possibility.
     
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  6. braided lines and a caliper rebuild imo

    EDIT: maybe get a master cylinder rebuild as well, i know there is a kit for my bike so im sure there will be one for a spada.
     
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  7. Check the lever isn't bent slightly. If it is it won't pull back far enough to activate the pressure in the master cylinder properly.

    CHECK THIS BEFORE DOING A REBUILD OF THE BRAKE SYSTEM!

    Why? I had the same problem. Rebuilt the calipers, master cylinder and replaced the brake lines. Bled it like a muthafukka for three days with no improvement. In desparation I replaced the brake lever with a new one and, Viola, perfect brakes.

    Even if the lever LOOKS ok , replace it anyway to see.
     
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  8. nice point doug, its also good to have spare levers even if its not the issue. i carry some with me under my seat, nothing worse then being stuck in the middle of no where because you dropped your bike like a dickhead and snapped a leaver.
     
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  9. Cool, thanks for all the responses everyone! Might try the cheap and easy lever replacement first, see it that works. If not, well then it's not my bike and the current owner thinks it's fine as is, so don't think the MC rebuild or braided lines will be happening.

    Good to hear that I was on the right track though.

    Cheers again, much appreciated.

    John
     
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  10. Keep us posted.
     
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  11. mmm i dont agree with those responses
    i will write a way to diagnose properly asap,
    on phone atm n knackered..
     
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  12. Doesn't matter if you agree or not. Theyre legitimate fixes. If you have another way please enlighten us.
     
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  13. I'd be interested to hear the alternative. We've already covered the rotor, pads, caliper, brake lines, master cylinder and even the brake lever. I'm not sure what's left?
     
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  14. yer wanted to respond to the above sugest in detail
    from laptop , its wrong to advise on brakes guys if
    your not expierenced / qualified understand ur trying
    to help but jees theres several mechs here that can help.

    braided lines ???
    rotor / pad thickness??
    anyway i am again struggling on phone but try n walk through.
    ( yer btw qualified brake specialist ) .

    you can duagose first or simply bleed brakes properly
    either way is cool.

    bleed brakes 101 ( please ignore urges to pump up pressure
    or anything wildly aggressive ).

    beer bottle/ cordial bottle n ckear hose that fits neat over bleeder.
    pipe to very bottom of bottle.
    master lid u gotta be careful with on a bike cos of spilage.
    brake fluid is like acid to paint so protection peeps.
    loosen bleeder
    depress lever
    close bleeder
    now carefully allow lever back.
    its important its slow n steady back - depending on how fast ur
    particur master compensates.

    repeat over etc.

    if unsuccesful - reasons / options an diagnose.

    ok so if maybe u have a very slow compensating master this
    will catch out peeps trying to bleed in a hurry.

    u can see this problem if you open bleeder after lever is returned
    a bit a fkuid in tube sucks back up .
    if this is problem rapid bleedin pump up etc will actally make system
    worse as air will suck in from bleeder.

    options for above
    return lever even slower n wait longer between each return
    gravity bleed ; leave bleeder open and have a few beers ,
    n font run outa fluid in master - this works pretty good but takes
    several beers , if its heaps slow even take a risk on fluid level
    n leave overnight

    pressure bleed , messy without proper equip but pressure from
    master fluid ie a lid with say a tube / hole n gentle aur pressure
    gentle will firce gkuid through system .

    vacuum works same opposite end - from bleeder.

    to diagnose problem to identify master fault or hose etc.

    you need a brake hose clamp ( not vice grips ) .
    apply clamp to top part if hose .

    lever should be rock hard id master is good with no air in master.

    now a few options here deoending on result .
    if rock hard put at bottom of hose to be sure hose is ok
    if hose us faulty to level ur saying though it would be visibly
    swelling - lots from a interbsl rupture ( braided lines have no
    advantage buy s std one unkes yiu want it to look pretty )

    that pretty much telks you niw where n what orobkem is.

    you can further test as as you improve / repair buy doing
    a drop test to see hiw far kever moves when you remove clamp

    o hang on go back - if first test was rkck hard at a quick pull
    but fades if you play n tweak - hard to describe a master bypass

    anyway thats nuf fir now need ta go
    just ask qu.
     
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  15. o doug tbere not legitmate at all
     
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  16. Yeah I have a question. Did you read the part in the OPs post about having bled the brakes twice before you assumed everyone else didn't know what they were talking about when they suggested other possibilities?
     
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  17. yep i read it
     
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  18. Fair enough. It's the reason why I didn't bother suggesting the OP bleed the brakes again, I assumed they'd done it right the first, or at least second, time around.
     
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  19. i will fix up spelling when i get on my pc
    maybe tidy up the brake bleeding part for a sticky if want
    so many people struggle with it .

    and make the diagnose section more fluent
    ( heck im trying to watcb t v n drink beer atm )



    or if people dont wa nna hear it ill delete it
     
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  20. Let me know how it goes, my Spada has pretty soft front brakes despite new brake pads and cleaned the caliper pistons. rear brakes are fine though
     
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