Post by oldchopperguy on Mar 14, 2013 21:41:55 GMT -5
Need advice...
In a previous thread, I related my rear-disk brake stopped working, with the lefthand brake lever going limp. Inspection showed the master cylinder was very bad, and appeared to be allowing the brake fluid to pass around the piston, providing virtually no pressure on the rear caliper.
Well, today my new master-cylinder/lever/stoplight switch arrived and I got it installed.
I opened the bleed-valve on the rear caliper and filled the new master-cylinder with fluid. I began to gently pump the brake lever until all the old fluid was flushed from the line, and clear, new fluid was coming out.
I closed the bleed-valve and expected brakes. WRONG!
The lever just goes to the handlebar with NO hydraulic resistance or brake activation at all.
I've never serviced hydraulic brakes, so I'm not sure what to expect, but... when flushing out the old fluid, and filling the line, the fluid coming out of the bleed-valve on the caliper was only a "trickle"... I would think every pump of the lever would produce a strong "squirt".
At this point, the new master-cylinder reservoir is full. There's clean fluid coming out of the caliper bleed-valve. The valve has been closed and all should be "go". BUT... The brake lever just closes with NO hydraulic pressure at all.
Any hints are appreciated!
What's the likelyhood of my new master-cylinder being bad? I don't think so, as there's no sign of fluid by-pass like the old one showed.
Is it possible the caliper-cylinder/pistons are ALSO bad, allowing fluid to just blow by the pistons and recirculate with no pressure or braking? Experiencing two related failures is not common, but with these Chinese scoots, ANYTHING is to be expected.
Next step I guess, is to replace the 2-piston caliper. If that doesn't work, then replace the line. THAT comprises the entire rear-brake assembly (except for the actual disk).
There are no leaks, and the fluid level remains full. But, the brake lever generates NO pressure or braking at all.
Has anyone else experienced this?
This is driving me nutz!
Thanks one and all,
Leo (still walking) in Texas
In a previous thread, I related my rear-disk brake stopped working, with the lefthand brake lever going limp. Inspection showed the master cylinder was very bad, and appeared to be allowing the brake fluid to pass around the piston, providing virtually no pressure on the rear caliper.
Well, today my new master-cylinder/lever/stoplight switch arrived and I got it installed.
I opened the bleed-valve on the rear caliper and filled the new master-cylinder with fluid. I began to gently pump the brake lever until all the old fluid was flushed from the line, and clear, new fluid was coming out.
I closed the bleed-valve and expected brakes. WRONG!
The lever just goes to the handlebar with NO hydraulic resistance or brake activation at all.
I've never serviced hydraulic brakes, so I'm not sure what to expect, but... when flushing out the old fluid, and filling the line, the fluid coming out of the bleed-valve on the caliper was only a "trickle"... I would think every pump of the lever would produce a strong "squirt".
At this point, the new master-cylinder reservoir is full. There's clean fluid coming out of the caliper bleed-valve. The valve has been closed and all should be "go". BUT... The brake lever just closes with NO hydraulic pressure at all.
Any hints are appreciated!
What's the likelyhood of my new master-cylinder being bad? I don't think so, as there's no sign of fluid by-pass like the old one showed.
Is it possible the caliper-cylinder/pistons are ALSO bad, allowing fluid to just blow by the pistons and recirculate with no pressure or braking? Experiencing two related failures is not common, but with these Chinese scoots, ANYTHING is to be expected.
Next step I guess, is to replace the 2-piston caliper. If that doesn't work, then replace the line. THAT comprises the entire rear-brake assembly (except for the actual disk).
There are no leaks, and the fluid level remains full. But, the brake lever generates NO pressure or braking at all.
Has anyone else experienced this?
This is driving me nutz!
Thanks one and all,
Leo (still walking) in Texas
..BAD TO THE BONE..
ABSOLUTELY NOTHING!!! Just "limp".
