Captain Scarlet Posted April 11, 2009 Report Share Posted April 11, 2009 Right I know the inevitable answer here will be; "Send it back to Hope!", but not being able to contact until Tuesday and the prospect of having to send the brake back and wait a few days, I'm open to consider other options or see if anyone else has shared similar problems.Basically I've got a rear mono trial (which I ordered direct from Hope last week), its still in the bedding in period but I know there isn't something quite right with it.Often when I hop on the rear wheel or go to rear, I get a horrible clonk when I land. I got off the bike, held the rear brake and pushed the rear wheel back and forth with my hand (noticeable movement followed by a clonk).Through a process of elimination, I have found that it is not the caliper or the rotor itself (as this moves in unison with the wheel).I looked at the pads from above, and found that for some reason one pad (just the pad on the bore cap side) has a large amount of wobble, whilst the other pad has none.There is also a large side to side movement at the retention pin itself (usually with most pad wobble the backing tab of the pad just pivots on the rentention pin), its almost as though the hole in the pad backing which the retention pin mounts through, is too large for the pin and allows for excess movement.I guess a way to confirm this would be to put my front pads in the rear caliper, but I'm fairly certain of my assumption by the amount of noticeable pad wobble I can see.Has anyone else experienced this kind of pad wobble, whether it is a defect or mismade batch of pads?Any feedback into this would be great. Quote Link to comment Share on other sites More sharing options...
Ali C Posted April 11, 2009 Report Share Posted April 11, 2009 try sanding off the paint on the back of the pad.If that doesn't work, it may be a case of waiting untill the piston as made an imprint big enough to keep the pad still, its not an uncommon problem for the pads to clunk and make noises. Quote Link to comment Share on other sites More sharing options...
JT! Posted April 11, 2009 Report Share Posted April 11, 2009 Have you checked if the rotor bolts are tight? Quote Link to comment Share on other sites More sharing options...
JonMack Posted April 11, 2009 Report Share Posted April 11, 2009 I'm with Ali, sand the back of the pad down and keep riding it. I also apply copper slip to the back of mine which helps them stick to the piston, and in no time it'll have made a nice ring in the pad backing.Don't cry Thomas Quote Link to comment Share on other sites More sharing options...
Captain Scarlet Posted April 11, 2009 Author Report Share Posted April 11, 2009 (edited) Have you checked if the rotor bolts are tight?I have found that it is not the caliper or the rotor itself (as this moves in unison with the wheel).I'm downright certain its a problem with the pad, as I said, only one pad is doing it (one is locked solid, the other moves a ridiculous amount).I've also had my front mono trials from new, and have replaced the pads in that in its lifetime, and did not experience anything like this either of those times.Forgot to add, the clonking the brake makes is a similar volume to that of a freewheel skip. Edited April 11, 2009 by Captain Scarlet Quote Link to comment Share on other sites More sharing options...
Ali C Posted April 11, 2009 Report Share Posted April 11, 2009 yep, Stans brake makes the same noise! I am afraid you may just have to live with it (unless Ads can think of a solution?). Quote Link to comment Share on other sites More sharing options...
JT! Posted April 11, 2009 Report Share Posted April 11, 2009 I'm downright certain its a problem with the padForgot to add, the clonking the brake makes is a similar volume to that of a freewheel skip.Fair enough, it's just that mine was doing the exact same thing, even with that same noise yesterday. And it was the bolts. Quote Link to comment Share on other sites More sharing options...
D A N N Y Posted April 11, 2009 Report Share Posted April 11, 2009 Have you checked if the rotor bolts are tight?It happened to me too and tightened the bolts and the clunking stopped.Danny Quote Link to comment Share on other sites More sharing options...
DrDoom Posted April 11, 2009 Report Share Posted April 11, 2009 http://jforjustice.co.uk/banksters Quote Link to comment Share on other sites More sharing options...
Muel Posted April 12, 2009 Report Share Posted April 12, 2009 I wouldn't think that would stop it, mine did it because they had oil on the back of the pads.Just ride it, they'll soon dig into the paint and it'll stop. Quote Link to comment Share on other sites More sharing options...
crispyboy Posted April 13, 2009 Report Share Posted April 13, 2009 Just ride it, they'll soon dig into the paint and it'll stop. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted April 13, 2009 Report Share Posted April 13, 2009 1. Sand paint off back of pads2. Degrease piston surface and back of pads3. Ride until there is a shiny ring on the back of the pads4. This will make the pads stick to the pistons using the same principal that a sticks a rotor to the pad surfaceCopper grease makes it worse as the pads will then slide even easier Quote Link to comment Share on other sites More sharing options...
Captain Scarlet Posted April 13, 2009 Author Report Share Posted April 13, 2009 Can I just ask why sand the back of that pad? Surely that will make the problem worse as it gets rid of the groove/rough surface that has already started being etched into the back of the pad by the piston, or is it a different principal of grip here?I've heard of using the copper grease before, my understanding as to why it is used, is to work almost as a filler, as well as muting/masking the noise that is made when the pad moves back and forth (rather than an audiable clonk of pad against calliper).Cheers for the input into this, I'll examine the brake before work tomorrow, and if an obvious reason as to why one pad moves a tremendous amount doesn't become apparent, I'll try the sanding of the back of the pad and will keep you informed of the progress.Thanks for the advice. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted April 14, 2009 Report Share Posted April 14, 2009 Can I just ask why sand the back of that pad?To speed up the bedding in, the paint acts as a lubricant. Quote Link to comment Share on other sites More sharing options...
Captain Scarlet Posted April 14, 2009 Author Report Share Posted April 14, 2009 Right upon examination today, I found that the pads already had an obvious ring created by the piston, so didn't bother to sand down the back of the pad.I went and had a little ride and it did feel a bit better, but was still a bit of an occurance so I gave Hope a call, chap on the phone didn't know what to suggest and sent out a set of pads in case of a bad batch.Comparing with my front mono trials, I guess the wobble in that is minimised by the amount of brake dust and crap build up in the front caliper (well at least the knocking noise is muted because of this).I'm hoping that the pads I've got in at the moment on the rear, are slightly too small as that would make for excessive movement inside of the caliper (where a better fitting pad obviously has less room to move).After I've tried these new pads out I think its a case of riding it through. Quote Link to comment Share on other sites More sharing options...
Captain Scarlet Posted May 17, 2009 Author Report Share Posted May 17, 2009 Sent the brake back to Hope, and got a new one under warranty (not sure if it was a new calliper of whole new brake).Quick examination showed little pad movement, soon whacked the calliper on to find the same problem. I've given it about 2-3 weeks (I'd officially say bedded in now, as I've not had much chance to ride), and the problem is only worse now, think its another phone call to Hope and back to the less powerful but less annoying Magura for me. Quote Link to comment Share on other sites More sharing options...
Muel Posted May 17, 2009 Report Share Posted May 17, 2009 It's not an unsolvable problem, I always find it happens with new pads, takes ages to go away aswell.Best thing I did to solve it was ride in the rain, maybe it helped the pistons dig the groove into the backs of the pads or rust the backs of the pads or something. Worked anyway. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted February 17, 2010 Report Share Posted February 17, 2010 I've given it about 2-3 weeks (I'd officially say bedded in now, as I've not had much chance to ride), and the problem is only worse now, think its another phone call to Hope and back to the less powerful but less annoying Magura for me. If you follow the steps I put above, it will solve the problem... (Sorry for bump, just had to search for this thread for a customer and thought I'd add another reply). Quote Link to comment Share on other sites More sharing options...
Rusevelt Posted February 17, 2010 Report Share Posted February 17, 2010 yep, Stans brake makes the same noise! I am afraid you may just have to live with it (unless Ads can think of a solution?). My old mono trials had the same slight forward and back play, and my new mono brake does the same. i just put up with it. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted February 17, 2010 Report Share Posted February 17, 2010 i just put up with it. You could just solve it using the steps I put above 1 Quote Link to comment Share on other sites More sharing options...
psycholist Posted February 17, 2010 Report Share Posted February 17, 2010 It's a nasty sound alright, a friend of mine actually refused to take my bike out trialsing yesterday while I was in work because the sound freaked him out too much. I'm going to have a look at whether I can make up a bracket from thin Aluminium that fills the space between the brake pads and the sides of the calipers to see if giving the brake pads less forward/backward distance to move will reduce the volume of the clunk - the pistons won't be able to dig a recess in the back of the pads to hold on to if the pads are moving too much anyway. I'm using my brake on the back of a stock bike, so the movement is slightly more noticeable and one of the reasons for going to disk was the irritating noise from Maguras. Still, unless it proves very mechanically unreliable I'll never go back to Maguras or V's again though - epic bite and hold and wet grass/rain no longer make any difference to performance ... Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted February 17, 2010 Report Share Posted February 17, 2010 1. Sand paint off back of pads 2. Degrease piston surface and back of pads 3. Ride until there is a shiny ring on the back of the pads 4. This will make the pads stick to the pistons using the same principal that a sticks a rotor to the pad surface Copper grease makes it worse as the pads will then slide even easier See above!!! 1 Quote Link to comment Share on other sites More sharing options...
Mark W Posted February 17, 2010 Report Share Posted February 17, 2010 Epic quest to make pads perform. You really don't need to go to that much trouble - just do what Adam suggested! My brake did exactly the same, and that solved it straight away. Took 2 minutes to do, absolutely no hassle. 1 Quote Link to comment Share on other sites More sharing options...
psycholist Posted February 17, 2010 Report Share Posted February 17, 2010 Excellent... In my best Mr. Burns voice... Keeping the bike silent makes me less guilty about messing about on the bike in urban areas at 2am... I'll pull the lot apart this evening and see how much progress the pistons have made in digging into the back of the pads and see about helping them... Quote Link to comment Share on other sites More sharing options...
Mark W Posted February 17, 2010 Report Share Posted February 17, 2010 Cool, good plan. Just follow what Adam said and don't lube up the back of the pads or anything. Just meths, towely-crap and a bit of time Quote Link to comment Share on other sites More sharing options...
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