| Author | Message | ||
     Firstbatch |
My front brake lever "freeplay" is about 1" of travel measured at the end of the lever before I get much if any braking. From that point the brake feel is fairly abrupt and could be described as grabby. In comparison to my other rides this is way to much free travel. So, just finish up a brake bleed using a Mighty-Vac method and the condition remains the same. Have not ridden yet, raining right now, but I was unable to bleed out any of the free travel. Is this amount of lever travel normal or within spec for a Uly?? Is it possible that the master cylinder is defective? bike has less than 2k mi. May have to try the Henrik bleed method, but Mighty-vac has always worked for me in the past. Any ideas on how to correct this issue? | ||
| Rogue_biker |
Did you inspect the brake pad life? I had a similar issue to yours on my '06 Firebolt. At 5k miles, I noticed the front brake travel was more than when the bike was new. 6k miles on it, I bled the brake fluid but there was no change in brake lever travel. Then, I inspected the front brake pads: The front brake pads only had 1/3 life left at 7.7k! I replaced the pads with new ones, then bled the brakes again. Brake travel is now back to normal and the slight sponginess is gone. | ||
| Firstbatch |
Ok, to close out the issue...a good brake bleed and then an overnight zip tie of the lever to the grip and I now have about 1/2" freeplay and a firm linear brake lever feel. All is good in brake-land | ||
| Jim32092 |
A little trick I use--next time you get spongy feel just take the caliper bolts off and tilt the caliper a little back and forward--I think a little bubble gets trapped in the top of the caliper some how from moisture in the fluid. I also like to change the brake fluid when I put on a new rear tire. It's my signal to change fork oil as well. | ||
| Thumper74 |
Some neat things to try... On bikes, I'm anal about brakes. There are no emergency brakes... You can use a vacuum bleeder, they do a great job just don't let the resevoir go dry. If the good bleeder doesn't do a satisfactory job, I resort a small funnel supported in the resevoir, fill that up with brake fluid, put a catch pan under the caliper and let gravity do it's thing. As far as air bubbles being compressed? If you reduce the compression, they would probably expand. Diffusion seems like instead of one bubble, you would have a bunch of tiny bubbles. The same volume, just spread out... My guess would be that the casting/machining flaws that 'hold' the bubbles in the caliper would be forced to release the bubbles where they could make they're way to the resevoir. Also remember that brake fluids can absorb moisture/humidity through the rubber lines. As you ride, that moisture can boil causing it to be a vapor which is compressable (the water while a crappy hydraulic fluid for that reason will will still not compress untill it's a vapor) and you loose performance. Once the brakes cool down where the vapors can condense again, you'll be right back with a good feel. | ||
| Ratbuell |
I've had the best luck starting my bleed with full compression of the caliper pistons, i.e. new brake pad installation. Push them all way back into the caliper with the reservoir cap off either by removing the caliper and manually compressing it, or by removing the caliper mount bolts and twisting/levering the caliper back and forth a bit on the rotor, using the rotor as the "tool" to push the pistons back in. Reinstall the caliper and bleed from there. For some reason removing as much fluid as possible from the caliper seems to make a HUGE difference. My S2 lever twitches less than 1/8" from static position and I'm slowing down, I love it. I couldn't get it to the grip if I tried. |
