slack Posted January 29, 2007 Report Share Posted January 29, 2007 Hello everybody, new to TC. I'M having loads of trouble with the rear brake on my scorpa sy. When i was doing a trial after the third lap the brake started to fade until it actually gave up all to gether. So put fresh pads(the correct ones for the bike) in bled the system & got a good peddel. I did another two trials & the same happend again so back bled the system again good peddle, once again & the same has happend i'm at my wits end,any help or advice would be gratefully accepted.i've priced a new master cylinder Quote Link to comment Share on other sites More sharing options...
essex rider Posted January 29, 2007 Report Share Posted January 29, 2007 No experience of scorpa brakes but it sounds like the M/Cylinder has gone. You may be able to get new seals but not too sure of this. Good luck though, they do get VERY annoying. Quote Link to comment Share on other sites More sharing options...
blocky Posted January 29, 2007 Report Share Posted January 29, 2007 Bleed the system again to get a good pedal and then leave it presurised overnight. Perhaps a breeze block lodged on the pedal. Then check for signs of fluid loss in the morning Quote Link to comment Share on other sites More sharing options...
scorpa3 Posted January 29, 2007 Report Share Posted January 29, 2007 Bleed the system again to get a good pedal and then leave it presurised overnight. Perhaps a breeze block lodged on the pedal. Then check for signs of fluid loss in the morning You didn't say if the fluid level is going down? I assume that this is the case, so the above idea will help you locate the leak. Quote Link to comment Share on other sites More sharing options...
slack Posted January 29, 2007 Author Report Share Posted January 29, 2007 Bleed the system again to get a good pedal and then leave it presurised overnight. Perhaps a breeze block lodged on the pedal. Then check for signs of fluid loss in the morning You didn't say if the fluid level is going down? I assume that this is the case, so the above idea will help you locate the leak. no the bike is not loosing any fluid,i susspect the master cylinder is at fault but want to rule all other possiblities out first before i take the plunge & buy a new one.CHEERS & thanks for your quick response. keep up the good work T.C. Quote Link to comment Share on other sites More sharing options...
scorpa3 Posted January 29, 2007 Report Share Posted January 29, 2007 If you are not loosing any fluid, then there is obviously no leak. However you are still loosing pressure, this means the fluid must be passing from the pressurised part of the master cylinder back into the reservoir. The solution if this is the case, is to fit a new seal kit to the master cylinder. But before ordering one, first check for availability and cost. Then strip out the old seals and check the bore for serious corrosion. If it is pitted, a new seal kit will probably not cure the fault as the fluid will still bypass the new seal. I assume the repair kit will be available for the rear, I've only ever changed front ones myself. I hope this helps. Quote Link to comment Share on other sites More sharing options...
phb Posted January 30, 2007 Report Share Posted January 30, 2007 i had same problem on my 03 scorpa changed seals and was ok for a couple of trials then it did it again put new master cylinder in and it was fine after, a bit of a pig to get at though Quote Link to comment Share on other sites More sharing options...
scorpa3 Posted January 30, 2007 Report Share Posted January 30, 2007 Sorry to confuse things even more but I've been thinking about this over-night (yes, sad I know) If the seal has gone, it would loose brake pressure almost straight away. Certainly before you had chance to do a couple of trials. I wonder if the problem is that the brake lever is adjusted too high and it is not letting the piston move far enough within the bore to allow new fluid in? Then as the pads wear, you loose brake pressure because no new fluid is getting in to replace the travel left by the pad wear. You could try slackening off the pedal adjuster to give more free play and see if this helps. (As with the post above, IF this is the problem, fitting new seals wouldn't help because the problem is adjustment.) Following this train of thought, it could also just be a case of a sticking piston which might simply need freeing off. Quote Link to comment Share on other sites More sharing options...
nutter Posted January 30, 2007 Report Share Posted January 30, 2007 (edited) I had this problem and it was the seals in the master cylinder, changed the shuttle complete with seals and the problem was cured Edited February 6, 2007 by nutter Quote Link to comment Share on other sites More sharing options...
slack Posted January 30, 2007 Author Report Share Posted January 30, 2007 Thanks everybody for letting me pick your brains(coz mine are scrambled)i'll try all your suggestions & get back to you all with the outcome. And once again thanks very much. CHEERS. Quote Link to comment Share on other sites More sharing options...
boofont Posted January 30, 2007 Report Share Posted January 30, 2007 Master cylinder seals for sure. BVM sell the kits for about Quote Link to comment Share on other sites More sharing options...
slack Posted February 4, 2007 Author Report Share Posted February 4, 2007 Hello guys & girls just to update you's on Scorpa rear brake problem, took the master cylinder brake line & calliper down to my local trials shop on saturday to get new master cylinder. they told me sherco was the same but when i got there totally different,glad i took my old one down or would have gettin the wrong one (would not have been happy coz was assured it would have fitted over the phone) any way bought a seal kit put it in fitted back to bike,swine to bleed got good brake had good trial today(apart from circlip on slave cylinder snapping on the clutch did some running repairs bled the system & back to finnish the trial) last lap lap then brake started to fade again,not much pressure on peddal but if you stand on it hard it try's to work i'me goin to take every thingapart & clean this week & try that CHEERS. P.S I know the problem is stairing me straight in the face but it has got me & my mate beat. Quote Link to comment Share on other sites More sharing options...
scorpa3 Posted February 4, 2007 Report Share Posted February 4, 2007 Is the piston moving full in the master cylinder? If it doesn't move enough, it won't draw more fliud in from the reservoir. Anothe idea, does the efficiency come back when everything cools down? I was wondering if your problem is the pads overheating? Quote Link to comment Share on other sites More sharing options...
slack Posted February 5, 2007 Author Report Share Posted February 5, 2007 As to your first question i'me not sure that is why i was goin to buy a new master cylinder, but when i went down to the shop the one he said would fit was completly different,& he did not have the origonal one so i just bought a new seal kit. the answer to your other question is no once the bike has cooled off the brake is still poor with no pressure,cant bleed it with the peddle have got to use syringe to get good brake pressure. i'm goin to strip the calliper this week & put new brass washers on the banjos to see if this works & if not well i'll order a new m-cylinder from Birketts. Thanks for your assistance Scorpa 3. Quote Link to comment Share on other sites More sharing options...
austini Posted February 6, 2007 Report Share Posted February 6, 2007 Had a similar problem on a sherco, the problem was a blocked inlet hole (through corrosion) in the master cylinder, where the resevior pipe enters the master cylinder there is a small pinprick hole that goes through to the piston make sure thats clear. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.