Oh where, oh were are my front brakes.


7 replies to this topic
  • unkle_george

Posted March 11, 2004 - 07:13 PM

#1

I've been noticing the free-play in my front brake lever keeps increasing. Seems like I have 3/4 free play and only the last 1/4 where the brake actually starts to grab.
I checked the pads, they're almost dragging on both sides and the adj screw on the lever is almost all the way out. So Hmm, I thought. Maybe they need bled.
Half a can of DOT 4 later, still no improvement. I notice that there isn't really any sponginess to them; just on the first 3/4 of the piston stroke a little bubble of fluid actually shoots up out of the hole in the bottom of the reservoir. I may have had the lever too tight, dropped the bike and forced the lever in and blown up something in the master cylinder.
Anybody else experience this? :)

  • gfergtr74

Posted March 11, 2004 - 08:41 PM

#2

I am not very familiar with the master cylinder on these bikes yet but from previous expierence with other brands this can be caused by a faulty seal on the piston inside the m/c. Make sure when you are bleeding the brakes that the fluid level doesn't get too low. That can suck air into the system and you can sit there for hours on end.

  • Hamish

Posted March 12, 2004 - 03:06 AM

#3

Had a similar problem with my 2 smoke. Watch the disc and caliper very carefully as you squeeze the brake. If the caliper isn't floating freely on the pins, or the pins are worn, the caliper will acually pull the disc to one side when you apply the brakes. This action take up a good percentage of the master cyl's stroke, causing the problem you described. Yamaha in their wisdon decided not to list the pins/seals as a seperate part :), you gotta buy the whole caliper (yeah right!) The pins rarely wear, but the inside of the caliper does. Just get someone to drill the caliper out and sleeve it.It's a good idea to lightly grease these pins whenever you have the wheel out to prevent wear. The rears are generally in worse condition due to the amount of water and dirt that gets thrown around that area.

hope this helps,
Hamish

  • unkle_george

Posted March 12, 2004 - 06:25 AM

#4

Thanks guys, I'll give that a shot. New MS seals can't be too bad, would be worth taking it all apart and putting on stainless lines too.
I'll remember to check out the caliper next time I have the wheel off.
Thanks
- Ryan

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  • captain_S

Posted March 12, 2004 - 12:38 PM

#5

If you mean you gotta pump up the lever to get pressure on the brake,yip tye the lever to the bar over nite,holds the circut open and lets the air out :)

  • RichBaker

Posted March 14, 2004 - 08:03 AM

#6

Check that the rotor isn't bent.....I coned 2 rotors on my 90 YZ-WR and it felt like you describe. Ended up putting an XT350 rotor on it...

  • Chas_M

Posted March 21, 2004 - 01:29 PM

#7

Before you start replacing parts, if you haven't already tried this, gently pry the pads away from the rotor with a large screwdriver - - then pump the brakes until firm. Repeat once or twice. This simple process has helped a lot with KTMs, Suzukis and Hondas.

  • Treebark

Posted March 24, 2004 - 06:14 AM

#8

First observe the caliper action at rotor see if rotor bent or caliper not sliding freely on pins. Another thing to observe is that the M/C piston is returning, maybe stuck due to a rolled over seal or seal is ripped and not allowing piston to return. If all that's fine then I would use a vaccum pump to bleed the brake system or try removing the caliper and bleed system with caliper above the M/C. Of course you'll have to but some thing between pads to keep piston from popping out. May need more than two hands for this but will work.




 
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