Tom R Posted September 17, 2011 Report Share Posted September 17, 2011 Hi guys, has anyone got an idea why my pads will not hit the rim squarely? I've tried resetting it many times but every time I pull the brake lever the pad extends at an angle and therefore have no brake force as it seemingly needs to be a perfect alignment. I've also noticed the pins holding the pads seem worn not allowing it to 'click' into place very well. I'm tempted to just spend the money and buy a whole brand new rear brake assembly to start from scratch with a perfect brake. any help much appreciated. Tom. Quote Link to comment Share on other sites More sharing options...
Luke Dunstan Posted September 17, 2011 Report Share Posted September 17, 2011 What sort of clamps are you using? Are the pads new? Quote Link to comment Share on other sites More sharing options...
Revolver Posted September 17, 2011 Report Share Posted September 17, 2011 Sometimes clamps will pull cylinders out of alignment when tightened. It just depends, I think a new C-clip thing can help in that situation. Try checking these things - Can you get a full range of adjustment with the clamps loose? If not, you may need to file the slots in your mounts. Do the pistons move when you've tighened the mounts? If so, your bolts may be bottoming out, try putting washers on top of the mounts, or (be careful!) cutting your bolts down a bit. And finally the original point, do the pads stop being square to the rim when you fully tighten the clamps? Replacing the plastic C-clip thing can help, You might also want to try filing the mounts so they are all level with each other - http://www.youtube.com/watch?v=NEezZeqmVO8. Post back with results! Quote Link to comment Share on other sites More sharing options...
Tom R Posted September 17, 2011 Author Report Share Posted September 17, 2011 thanks guys, they are brand new Rockman green Pads (amazing performance for the brief moment they stayed in alignment) I am using standard Magura clamps, with some bought spacers and washers allowing fitment of my carbon Brisa booster. When tightening up, the pads seem to be being pushed out of alignment (so one end of the pads contact the rim before the other). Leads me to think my setup is allowing too much movement so I think I might ditch my current setup and buy some new Echo clamps with metal washers which will hopefully hold everything more firmly. However, I'm not sure this will solve the pistons pushing the pads out at an angle to the rim...? Its freshly bled but a pretty old brake. Quote Link to comment Share on other sites More sharing options...
Kenny--Trials Posted September 17, 2011 Report Share Posted September 17, 2011 possibally a lazy slave? - get a whip if you want to sort it out Seriously though the way you have explained it sounds like a lazy slave cylinder. Mine does that slightly when its lazyer on one side than the other. The only thin i can suggest is set them up so they hit the rim squarely or wear them down until they hit the rim square by riding. Quote Link to comment Share on other sites More sharing options...
Theta2 Posted September 17, 2011 Report Share Posted September 17, 2011 thanks guys, they are brand new Rockman green Pads (amazing performance for the brief moment they stayed in alignment) I am using standard Magura clamps, with some bought spacers and washers allowing fitment of my carbon Brisa booster. When tightening up, the pads seem to be being pushed out of alignment (so one end of the pads contact the rim before the other). Leads me to think my setup is allowing too much movement so I think I might ditch my current setup and buy some new Echo clamps with metal washers which will hopefully hold everything more firmly. However, I'm not sure this will solve the pistons pushing the pads out at an angle to the rim...? Its freshly bled but a pretty old brake. When I bought spacers and washers the bolts were too long and needed to be cut down as when I pulled the lever the cylinders moved, as revolver said, either cut them down or try some washers under the heads (about 3mm worth). Should work a treat Quote Link to comment Share on other sites More sharing options...
Cap Posted September 18, 2011 Report Share Posted September 18, 2011 How old are the plastic cylinder washers on the magura brake clamps? If they are a bit worn they can mess with your brake alignment http://www.tartybikes.co.uk/rim_brake_spares/magura_hs33_cylinder_washer/c5p27.html If it isnt the bolts and spacers as suggested I would check them Quote Link to comment Share on other sites More sharing options...
Tom R Posted September 18, 2011 Author Report Share Posted September 18, 2011 great advice! Cheers. Lazy slaves seems to be an issue, as do the plastic washers, they're very worn so replacing them seems like a good idea. I'll also hunt down some more washers. Quote Link to comment Share on other sites More sharing options...
DeVal Posted September 18, 2011 Report Share Posted September 18, 2011 yeah as others have said if the cylinders are physically moving out of place when tight then the mount bolts are bottoming out on the frame threads before the clamps have compressed on the cylinder. as the others said you may need to cut the bolts down or if you prefere find your nearest building merchant that sells specialist bolts and get a size between the originals and the brake boosters bolts. Quote Link to comment Share on other sites More sharing options...
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