Sunday, August 8, 2010

Brakes ! (at last)

From the time I had made the local BMW dealer rebuild the brake calipers, I had never been able to regain a proper feeling with the brake lever. It felt spongy since, even after several fluid bleeds or nights spent with a strap on the brake lever. To get a firm feedback from the lever, I had to pump 3 to 4 times and it has always felt back spongy a couple of minutes later.

This is a big issue I've wanted to solve for weeks. After all if it goes on tracks (may I remind myself this is the main purpose of this bike ? ...), it is to support heavy braking sequences with high discs and fluid temperatures. This is why I had removed the Integral-ABS system from the bike and prefered a Goodridge braided hoses kit over it. Unfortunately, I've had very little faith in this kit so far considering the soggy feeling since fitting.

Ok, now let's get to the point. Yesterday, I unbolted the calipers one after the other and made each 4 pistons come out almost completely. I then carefully pushed them all the way back into place while preventing the others from moving. some of the pistons were hardly moving when brake was applied. And for those moving, they would come back to their original place when the brake lever was released. This is not what you expect from a brake piston. 

Now I don't know whether if these pistons were kind of blocked or if there still was air in the calipers, but it seems to have cured the problem. Brake lever has never felt so firm and I can't wait to give it a try on the road.

Brake calipers now feel like they actually can stop the bike

(Did someone say "rust" ? Both calipers' bolts look like that even though a BMW dealer is supposed to have rebuilt them. I thought they were going to replace these, but it seems they like troubles)

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