John O'Sullivan Posted June 22, 2003 Posted June 22, 2003 For those of us with a rear brake squeal: This posting on the Aussi site makes sense. this is a common problem on the sport models, the bike was delivered with not enough clearance on the brake lever.. (claim it on warranty) the brake lever needs at least 5-8mm clearance before it touches the master cylinder piston.If it's too tight, the brake fluid cannot expand in the master cylinder direction, as a result, the pads get some brake action, the whole system gets even hotter and it can become a complete lock up (there have been a few) Bernd is the author of this piece.
al_roethlisberger Posted June 22, 2003 Posted June 22, 2003 When you describe "brake squeal"... is this happening while riding, or just pushing the bike around?? I ask because we have discussed the "brake groan" from the rear when rolling the bike backwards. Mine used to do it when I first got it, then went away(after tapping the rear brake) but has started doing it pretty consistently lately. For now I was chalking it up to not being ridden enough over the last 4-5 months... sitting in the shop. Are we talking about the same thing? al
Guest callithrix Posted June 23, 2003 Posted June 23, 2003 That's funny I just made the same observation this weekend on my bike. I also attributed it to lack of use. I was hoping it wasn't the rear wheel bearings, I'll have to check into it today when I change my tires. I'm mounting Pirrellli Diablos.
twhitaker Posted June 23, 2003 Posted June 23, 2003 Mine was making the same "groan" until I tightened the bolts holding the caliper onto the mounting bracket. A while back Rich Maund wrote about his rear brake. I think bleeding the system was his cure.
John O'Sullivan Posted June 23, 2003 Author Posted June 23, 2003 Al, I think you'll hear this when pushing the bike around. I cleaned my rear pads and reinstalled them giving the assembly a good wash with brake pad cleaner as I'd read that rear brakes wear quickly. The posting I cross posted from the Aussi site was written by Bernd who works at Stein Deinse (Sp?). Another John
Guest Phil/TX Posted June 28, 2003 Posted June 28, 2003 I think I will check the pedal adjustment, as I had to put on new rear pads at 10,400 miles, about 80% worn, while the front were just showing a little ware, and I am a front breaker, just using the rear to trail brake in corners.
dlaing Posted June 28, 2003 Posted June 28, 2003 I think I have been running at zero clearance all this time as the lever rests at the stop! Kinda scary. No wonder I only got 16 thousand miles out of the rear brakes while hardly using. lubricating the piston helped get rid of the noise, but it was probably rubbing when hot and getting hot while rubbing. Not a good thing when it comes to brakes. Hey, perhaps this is why many of us suffer from high fuel consumption! Oh, and to bring up an old warning again, I had my rear tire changed the other day by a non guzzi bike shop and lo and behold they left the brake line detached and it was dangling near the exhaust. Atleast they seemed to torque the caliber holder bolt well enough, (another safety issue)
al_roethlisberger Posted December 13, 2003 Posted December 13, 2003 So while I had my rear wheel off, I liberally washed the rear caliper with generic brake cleaner... and so far the brake groan is gone. Now who knows how long this will last, but I washed a ton of brake dust and grime out of the caliper. The rear wheel rolls free for now, not that it seemed to drag before(beyond the groan when rolling backwards). The pads didn't seem very worn, so I don't think it was dragging enough to wear or induce any rolling resistance. Maybe just regular cleaning is the best medicine..... al
dlaing Posted December 13, 2003 Posted December 13, 2003 Maybe just regular cleaning is the best medicine..... al (Not that you are stupid, au contraire mon frere) But I think the pistons stick because of a build up of crud where the pistons meet the seals. Years ago, I posted how my dealer cured the drag by lubing aroung the pistons. This however only lasted a few months and the brake pads still wore out prematurely. The last time I cleaned the pistons they retracted nicely and the slightly noticeable friction completely disappeared. I just hope it lasts. FWIW I don't think these pistons are protected by a dust guard. The seal just keeps the brake fluid in.
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