Sorry to ask, and I'm sure this has been asked but can't get a good leaver on the front. I've changed the master cylinder three time for different units, used standard hose, two different braided, striped the caliper four times and greased the seals. Only thing I haven't tried is changing the pads. Disc looks good. Any help would be great because I'm running out of ideas and this is the last thing to do before MOT.
Try reading this....it should help......same principle http://ducatiforum.co.uk/f4/bleeding-clutch-8022/ AL
My is a 750ss with the single disc. I tried the original mastet cylinder, no dices so got a second hand unit still spungy. I bought new master cylinders, brembo billets (not genuine) still nothing. The clutch has always bleed fine but never been able to sort the front brake. Try all sorts, vacume, back bleeding had the caliper at all angles, tied the leaver over night, taken it all to pieces and started again, got no ware so stripped back down and started again. I spent over a year trying to get it sorted. This stopped me getting it on the road last year. Put new pads in today, still nothing. I'm using DOT4 fluid, I even bought some racing fluid at £15 for 300ml, still no good. Changed all the washers too. I bleed and bleed but no air comes out. Tried two different braided hose and the standard, then put the braided back on. I'll try the top banjo trick, last thing I can think off. Got a mate conning round to have a look tomorrow night, he's a car machice, hope he can sort it.
Get something like a big syringe or even a small squeezy bottle......push the pads right back and keep them back with a wedge. Fit the bottle to a rubber hose.......undo the bleed nipple and fit the other end of the hose onto the nipple......then upend the bottle. With the reservoir top open, squeeze the bottle with someone watching the reservoir..........FFS protect your paintwork though. It should work in normal circs, but I'm not sure about your replacement MCs etc etc. Good luck.... AL PS....If I can find time, I'll try to get over to your place and give you a hand, because I'm only about 10 miles from you...........at the moment it will be difficult as I am running Mrs AL backwards and forward from hospital.
So youve changed the hoses and the m/c and its still not better? Sounds like technique. I say that as I used to have similar issues, still hate bleeding brakes, and always ask a mate as whatever I do still, I can never bleed all the air out. Hopefully your mate will sort it
Thanks for the help, just looked and have bleed around half a litre through the system already. Hope we can sort tomorrow.
Cant remember where, Oulton I think, but we stood watching a guy bleed his brakes...pull brake and open valve let brake back tightin valve...went on for a while and emptied countless reseviors and still spongy...maybe coz he was letting air back in before closing valve! But with some peolpe you don't like to intervene...
I feel for you. I hate bleeding brakes. Everything you've tried and been told here already are good techniques and do work. I always tend to bleed the top banjo bolt first, then the bottom one, then the caliper bleed nipple. I've recently started using a simple vac pump from ebay £35. It's designed just for bleeding brakes and makes it all a bit easier when you get to bleeding the nipple. I might get moaned at for even saying this, but so long as you keep it clean, you can pump the new fluid you've bled out the system back in again. Save's keep buying more fluid if you're not actually using it, just don't leave it open to air for too long to start absorbing water or you'll be buggered as soon as it gets hot in the caliper and the water starts to boil.
Just felling the water here, but the caliper is 22 years old, and as far as I can see in the history is running the same seals. Could this be the problem as I'm 99% sure all the air is out.
Unless you have fluid running all over your brake disc, it won't be the caliper seals. PS.....Is the bleed nipple blocked by any chance? And...when you squeeze the brake lever, is there a blip of fluid in the reservoir? PPS....Another thought.......try filling the reservoir as much as possible, then put the cap back on and pull the lever several times right back, slowly each time, then leave it for a while.....You might find it starts to get some pressure, so you can then finish off.....I had to do this with another bike. AL
Thanks arquebus for the help. I've ordered seal kit anyway with new bleed nipple. Just out I interest, my machanic friend (who now works for UPS!!) stopped in at village motorcycles today and had a word with one of the blokes there who said that these bikes commonly have spongy front brakes, is this true. He said that if it stops ok that will be fine for the MOT but I think not. I'm I trying to achive the impossible??
I wouldn't say it was true........Mine is 97 SS and it has what I believe to be the original calipers and MCs...........I assume they are therefore original seals. Until last year it had the original rubber hoses (I could tell by the date on them) and they only got changed because I acquired some secondhand Goodridge hoses. Oddly, having fitted the Goodridge hoses I felt that the brakes weren't quite as good......that could have been because of a slightly sticky piston......but it has settled down now. Anyway, I can pull my lever back about 20mm before pressure starts (which is the proper dimension apparently) and then it gets harder.......I cannot get the lever back to the clip-on unless there is a tiny air bubble in there. However, saying all that above, I will admit they were a b*****d to bleed................just as bad as the the clutch. ....hence the tricks I used outlined in the clutch thread above. AL
I have had a few 600's and the road one on rubber hoses was a little spongy, but only because of brake fade when it got a bit spirited, or because the seal had gone again and was pissing oil on the disc!
I can pull the leaver about 10mm and the front wheel is locked solid, if I keep pulling the pressure rises until it hits the bar. I've stripped the caliper again today ready for the seal kit. I have done the old cable tie trick many times, the new MC i bought even have a bleed nipple at the top. I'll post an up date when i have fitted the new seals. Thanks again for all the help, if can't sort it out may be a thread for brake upgrade comming up!!
Is the lever adjustment screw in the right place......if there is one? On the OEM levers and many others there is a sealed adjuster in the lever near the pivot (OK, Fulcrum) which is set so that the lever doesn't push the piston too early, IE Free Play........if yours is moving only 10mm, I reckon your MC piston is keeping the port partly open. AL
If adjustable, I find the closer the lever, the softer the brake. Soon as the span adj goes out it is so much sharper. I run a different position for road and track and road needs a softer reaction and track needs 'feck I'm never gonna stop' initial bite Dont know why but all adj levers I have had have been the same
I don't mean adjustable levers, bradders, I mean the 'free play' adjustment; IE how much the lever moves before it starts pushing the piston..........if it is too 'tight', then this is genarally where boiling the fluid comes from. The adjuster in the OEM SS levers is usually covered with araldite or similar. AL
What do you mean exactly by spongy? comes back to bar fades after use needs pumping to get it to bite properly feels like wood pads fitted on the brakes does it work effectively?
