S4RS Front Brake

[lagerman72]

Hi all, just seeing if anyone has any advice before I call the shop and take a 2 hr ride (not that it would be a bad thing) down to OKC to the dealer.  My front brakes work great, if I give it one pump before really squeezing it.  I brake with two fingers and the first time I pull it, it comes it all the way to my finger that's wrapped around the throttle.  The subsequent times, it's nice and firm with only a little pull.  I know there must be air in the lines, however I've bled them for 3 straight nights, after lots of tapping, turning and squeezing (using the mityvac bleeder kit) and it seems fine.  I take it off the rear stand, roll forward a little bit and it's still nice and solid, roll back a bit hit the brake and again it comes into my finger.  I kept reading online and saw that the bleed nipples can suck in air and to use petroleum jelly and or Teflon tape around them, did this tonight and it seemed to help with the air bubbles while bleeding (both lines and the master ended up bubble free) however after a little roll backwards, it does the same thing.  I searched the threads and found one on reverse bleeding, from the pistons back, tried that but still get the same result.  I'm hoping if it's a master cylinder or a replaceable part, that it can possibly be replaced under warranty before it runs out in Feb, but I'm not sure what on the brake system is covered.

Sorry for the long post, but I appreciate any advice you have as I've run dry on ideas.  And now it's time to say cheers and read some posts while I enjoy a nice  .  Cheers!

[BK_856er]

Did you problems start after your bleeding efforts?

Sounds like it could be a funky master cylinder, which would definitely be a warranty item.

One easy thing to try is to crack reservoir cover a bit, apply the brake, tie the lever to the grip and leave it that way overnight.  Pesky bubbles might rise up to the reservoir.  Try to position the m/c as high as possible relative to the line - bike on sidestand, bars turned to the left - to give the bubbles an easier path straight upwards.  I used this method yesterday and it worked great, but I just had mush and not your exact symptoms.

BK

[lagerman72]

Thanks BK, I'll try that tonight!  Unfortunately the brakes have been this way since I bought it about 3 weeks ago.  I just happened one day last week to pull it twice and realized that there is a problem as the second pull was quite a bit firmer.

[hypurone]

Try the zip tie overnight thingy but it is most likely an internal bypass issue in the master and it will need to be replaced. The thing about air in the system is that while you get a spongy lever, it is a "consistent" spongy with a little pump up. Usually not a night and day diff as it sounds like you are getting. the first pump actually seats the "check-ball" or "valve" in the master and your second pump works as normal, when you let go, it unseats and you are back to where you started. Let us know...

PS Kind of a bummer as the bike sounds fairly new. Makes me wonder about mine... Especially after I found the sprocket assy retainer nut only finger tight!!

[krista]

Doesn't the s4rs have the plastic reservoir cups attached TO the master cylinder? If so, there's a bleeder screw IN it... take off the lid and bleed it there, too.

Chris

[lagerman72]

Doesn't the s4rs have the plastic reservoir cups attached TO the master cylinder? If so, there's a bleeder screw IN it... take off the lid and bleed it there, too.

Chris

Chris, I just looked and can't see anything other than the one on the master cylinder, next to the reservoir.  That's one of the original 3 that I've been bleeding.  Is there another one that I'm missing somewhere?

[aaronb]

did you get this fixed?

I know there must be air in the lines, however I've bled them for 3 straight nights, after lots of tapping, turning and squeezing (using the mityvac bleeder kit) and it seems fine.  I take it off the rear stand, roll forward a little bit and it's still nice and solid, roll back a bit hit the brake and again it comes into my finger.

so as long as you do not move the bike the brakes feel fine, right?  how about once they have been pumped back up, do they stay firm if you do not move the bike?

if moving the bike is the key factor, then i would inspect your rotors, one of them could be bent or warped excessively and pushing the pads back into the caliper.

[Capo]

Please.
Take your bike to the dealer.

[lagerman72]

did you get this fixed?

so as long as you do not move the bike the brakes feel fine, right?  how about once they have been pumped back up, do they stay firm if you do not move the bike?

if moving the bike is the key factor, then i would inspect your rotors, one of them could be bent or warped excessively and pushing the pads back into the caliper.

That is correct.  Capo, I'll be calling them first thing tomorrow to see when I can bring it to them and I'll post with what hopefully corrects it when they're finished.   Thank you all for the replies! 

[mxwinky]

Indeed, please oh please take it to the dealer.  And yes, your brakes are completely covered by your warranty.  Brake pads are considered normal wear items, but all the other components (master cylinder, calipers, lines, rotors) are covered so get it in there and have them fix it.  You very likely have a bad master cylinder.  Good luck and keep us posted.

[lagerman72]

I'm dropping it off at the Shuttle dealer tomorrow and they're taking it up the hwy (in a box truck) for Service at 10 AM on Thursday.  Hopefully I can report more after that, but he thought it sounded like the master sucking air when moving, so we'll see.

[lagerman72]

Just a update as I received my bike back.  The dealer did a great job and replaced the master cylinder, even though they couldn't 100% duplicate the problem, as it was under warranty.  I can tell you that it made a TON of difference.  Just a quick ride from the local shop to my work and the brakes are definitely what I was expecting!  Thank you all for the replies on this and thanks to OKC ducati/Tulsa Vespa for taking care of me and my bike.  Hats off to both!!   

[BK_856er]

Thanks for the update - glad to hear that you got it sorted out 

BK