Brake bleeding

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

JacquesM

Race Dog
WD Vendor
Joined
Jan 20, 2007
Messages
2,232
Reaction score
226
Location
Robertson
Bike
Yamaha TW200
A TW doesn't stop. So I'm trying to make a plan.

I took the back caliper and disc of my son's diseased pitbike and mounted them to the TW - it worked out all-right. I mounted the master cylinder and modified the brake pedal so that the leverage ratio corresponds to what was on the pitbike.

Now I'm battling big-time to get the system bled. It seems that I can't get all the air out of the system. I've taken the system off and now I'm trying on the workbench.

I've done the following:

Injecting brake fluid from the caliper at the bleeding nipple until the system seems to be full of fluid,

Bought a new master cylinder, which makes no difference,

Used another pipe,

Used the front caliper,

Renewed the banjo bolt washers,

and, and, and.

Working the plunger immediately starts pushing out the pistons  of the caliper, but not to the ratio it's supposed to. (It must send each piston out by 1mm for the 9mm stroke of the plunger.) I also does not have any clamping force at the pistons, you can hold your fingers between the pistons while they are being pushed out. There is also no resistance from the plunger. Every time I push the pistons back the fluid level comes back to the same place. There's also no more air coming into the reservoir when I push the pistons back. You can fill up the gap between the pistons, it does not clamp the spacing material at all.

There's obviously something obvious that I'm not observing.




 
Top