7 replies to this topic

[ping]

I'm new to the modern style trials bikes but have owned and serviced dirt bikes for over 30years. I recently bought a 2001 TXT and the rear brake felt soft/weak so I drained the lines and put fresh DOT4 fluid in.I've tried to pump, vacumn from the bleader, every trick I know but still get mush.I'm guessing their is a bubble hanging out in the high spot in the line where it enters the front of the swingarm.Sure would like some hints Thanks

[gtgasgas]

Buy an oil can or clean one real good, and push the fluid thru the bleeder in to the system. I would guess the master cylinder has a leak or air bubble.

[windlestone]

Can be one of those jobs that takes 10 minutes or hours and hours. Pushing the fluid back from the bleed nipple to the reservoir could push the seals in the master cylinder back on themselves. I hung the bike from the garage roof by the front wheel getting the reservoir as high as possible and get the brake hoses in as straight a line as possible. Air bubbles are trapped where the hose enters/exits the swing arm. Bleed the brake with the rear brake pedal, gently tap the brake hose in between, then finish off by pushing in the caliper piston with the bleed nipple cracked open. It can take ages, good luck

[NickJ]

I first use a 50ml plastic syringe and a short piece of plastic tube to 'back-flush' the fluid from the caliper to the reservoir, and then to finish take off the brake pedal and use a posidrive type screwdriver to push the master cylinder piston. You get about double the length of stroke doing this and it makes all the difference in getting any last bubbles out of the caliper.

Enjoy!

N

[B40RT]

windlestone, on Oct 16 2008, 08:19 AM, said:

Can be one of those jobs that takes 10 minutes or hours and hours. Pushing the fluid back from the bleed nipple to the reservoir could push the seals in the master cylinder back on themselves. I hung the bike from the garage roof by the front wheel getting the reservoir as high as possible and get the brake hoses in as straight a line as possible. Air bubbles are trapped where the hose enters/exits the swing arm. Bleed the brake with the rear brake pedal, gently tap the brake hose in between, then finish off by pushing in the caliper piston with the bleed nipple cracked open. It can take ages, good luck

I thought I wa the only one who resorted to weird things like hanging a bike from the roof, still, if it sorts the problem !!!

[B40RT]

windlestone, on Oct 16 2008, 08:19 AM, said:

Can be one of those jobs that takes 10 minutes or hours and hours. Pushing the fluid back from the bleed nipple to the reservoir could push the seals in the master cylinder back on themselves. I hung the bike from the garage roof by the front wheel getting the reservoir as high as possible and get the brake hoses in as straight a line as possible. Air bubbles are trapped where the hose enters/exits the swing arm. Bleed the brake with the rear brake pedal, gently tap the brake hose in between, then finish off by pushing in the caliper piston with the bleed nipple cracked open. It can take ages, good luck

I thought I was the only one who resorted to weird things like hanging a bike from the roof, still, if it sorts the problem !!!

[B40RT]

windlestone, on Oct 16 2008, 08:19 AM, said:

Can be one of those jobs that takes 10 minutes or hours and hours. Pushing the fluid back from the bleed nipple to the reservoir could push the seals in the master cylinder back on themselves. I hung the bike from the garage roof by the front wheel getting the reservoir as high as possible and get the brake hoses in as straight a line as possible. Air bubbles are trapped where the hose enters/exits the swing arm. Bleed the brake with the rear brake pedal, gently tap the brake hose in between, then finish off by pushing in the caliper piston with the bleed nipple cracked open. It can take ages, good luck

I thought I was the only one who resorted to weird things like hanging a bike from the roof, still, if it sorts the problem !!!

[JSE]

B40RT, on Oct 16 2008, 03:02 PM, said:

I thought I wa the only one who resorted to weird things like hanging a bike from the roof, still, if it sorts the problem !!!

I've never had to do it myself, but I've been assured that, as a last resort, it usually works.

Jon