| Author | Message | ||
     Chuckd |
Has this happened to anyone else? While cruising along about 50 mph (2000 S3T) the front brake starts to tighten up so I start to pull over, by the time I got to the shoulder the front tire was completely locked up. the rotor was blue!! After a 5 min. cool down the brake loosened up. I was not in my home town so I went to the nearest dealer. He said he could not find anything wrong but replaced the master cylinder anyway. That was in November and all has been fine until last weekend it happened again! Fluid is clean & topped off, pads look like new, the rotor is not bent, anyone have comments? Chuck D | ||
| Blake |
Chuck: If I recall correctly, another Bueller or three experienced similar problems due to pistons binding in the callipers. Something about dirt and/or the pistons heating up too fast (ahead of the calipers) and thus seizing until the caliper and piston temperatures stabilize to within an acceptable tolerance. The root cause however is possibly a dirty, maladjusted, or contaminated brake system. Check out the archives here.  FYI: I was able to quickly find the above archived discussion(s) using the "Search" Utility. Search was performed for only the "Knowledge Vault" with keywords +bind and +"front brake". | ||
| Gotbuell |
Have seen that problem when DOT 4 and DOT 5 fluids were mixed. Different boiling points. Also try cleaning the master cylinder, sometimes the bleed port gets contaminated and doesn't allow the fluid to return. Same holds for the pistons in the caliper. | ||
| Chuckd |
Thanks for the response. I removed the caliper and inspected, it was very clean, only 8k miles on the bike. Do you think an over-full master cyl. would do it? I changed the brake fluid to Motul RBF600 and left the level down a little but above the window. I'll keep you informed. Chuck D | ||
| Aaron |
Check to make sure the lever allows the master cylinder plunger to come ALL the way out, i.e. not preloading it any when the lever is released. If the lever is out of spec or if the pivot hole is drilled in the wrong place, this could happen. I've seen this once, although it wasn't causing the same issue you describe. Still it's worth checking. |
