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Rev 3 Rear Brake Problem


scorpa250
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Hi all,

Scropa 250 if you have the system on the bench make sure you put both bolts through the caliper otherwise you are effectivley forcing the caliper apart when bleeding which may explain your damp patch ( you will need a spacer for the longer bolt )

Having said that I still cannot my rear brake to bleed/be affective, the best I can get is about 20% effective.

I have tried;

Bleeding using bike own lever/rod (correctly adjusted)

bleeding using suitable bar direct into master cyl ( to get longer stroke, as reccommended by lampkins)

Removing whole system and lowering/raising to get the air out

Back bleeding from the caliper with syringe

Gravity bleeding ( raise caliper to same height as res and open bleed valve and remove res cap)

Tried 3 diferent lots of brake fluid

New brake pads

Fitted new master cyl

fitted two new sets of seals and pistons to caliper

ALL THE ABOVE DONE MANY TIMES........................AND STILL NO JOY

Stork 955 Have tried everything you have suggested but no differnce. Any other ideas.

( I am now going to try pulling my hair out )

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Well Got a new "o" ring fitted it put the whole lot back on the bike,used a screwdriver to push the m/cyl piston still no good !!!! there is fluid flowing but still no pedal!!! I made a new M/cyl

rod 10mm longer fitted it and on max adjustment there is about 25% braking .I back bleed from caliper to m/cyl but found the best way was to use a screwdriver. When i crack the nipple open push the screwdriver the fluid does spurt out dot just a dribble ...after another 1/2 ltr fluid refitted the rod still no good What next????????????????????????

Regards Scorpa250

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Just a quick thought, make sure you never have the bleeder open unless there is pressure on the m/cyl - i.e. push the pedal (lever etc), then open the bleeder until the pedal reaches the end of its stroke and hold it there, close the bleeder and release the pedal. This makes sure that you dont draw air back in. See if this helps,

Cheers,

Stork.

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Yep - there is still air in there. Did you prime the m/cyl first by just moving the piston and watching the reservoir? Its hard to describe but easy to do - after the bubbles stop apperaing in the reservoir then go on to the caliper. Tap fittings as you go, and take your time - slowly and gently is the answer - rushing just emulsifies the fluid and you go backwards.

Another thought, You have had the m/cyl apart correct? If so were both holes from the reservoir free and clear of rubbish?

Cheers,

Stork.

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not sure if it helps, i once had a ty250 with an intermittent poor front brake and was having to top the fluid up regularily and i diddnt spot the leak until the pipe from the master to the slave cylender burst (so must have been perished or something) and a new braided hose sorted the problem, perhaps your has a pinprick in it allowing air to draw in but not enough pressure to blow fluid out

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Gday Paul, just reading back through the thread, check out Ians way of priming the system with a syringe on the m/cyl (reservoir hose - on the first post page) That would definately get things going OK. It also makes sure there is a free transfer port in the m/cyl which could be your problem.

Cheers,

Stork

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I have tried Ians method on page one and things have improved a bit, now the system is about 50% effective.

I now think that scropa 250 and I have been supplied 'dicky' parts.

( I have noticed that 08 rev 3's have slightly different rear brake pedal that allows a longer stroke with the master cyl rod as the hole the rod locates into is further from the pivot point)

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Hello all, i have removed the whole system and it is hanging in the garage (caliper to top) have been tapping the whole lot with a spanner to try and get any air to the top will leave it for a couple of days tapping now and again will refit and bleed and see what happens will keep you all posted .

Happy Christmas to you all .

Scorpa250

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Good idea scorpa 250,might just do it. Still struggling with mine, I now think the problem lies with air trapped in the caliper ( Mine is 04 model with 4 piston caliper , is yours the same?) because of the internal shape/ position of bleed nipple and in particular the narrow port where the o-ring seats, make getting the air out difficult to say the least.

Let us know how you get on.

Might try this next; remove caliper/remove bleed nipple/hose and SUBMERGE the whole caliper into a bath of brake fluid to make sure its 100% full and reconnect to system without letting any air into system.

MERRY CHRISTMAS

PS make sure you dont trap the res feed pipe when refitting the master cyl.

GOOD LUCK.........MAY THE FORCE BE WITH YOU.

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Hello all,well...after having the whole system hanging up and tapping every time i went into the garage i refitted to the bike today,bleed (old school way) and there is 85% braking !!!!!

i will let my son do a trial and see how it goes ,its not as good as i would like but its the best its been .Will let you know how it performs in a trial. thanks again for all of the suggestions that everyone said i am sure it helped me get through knowing that i am not the only one that is having trouble .

Scorpa250

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