[Mischiefbrewer]

Hello all! So my build is almost done, 1980 CM400E “Rat-Brat”, after 3 months of careful planning and a complete overhaul of almost every system. I took her out for her maiden voyage today, but it was cut short because I realized the front brake was still not working. I was aware of this problem before, the brakes were not catching at all, so I cranked down the cable so the brakes would engage sooner and both brakes seemed to be pushing out, I even got it on the stand and rolled the wheel and tried it out, running and not, and it stops the wheel. But when I’m moving, nothing. This is (hopefully) the last hurdle I have to bring this old bike back to life, if anyone has any advice or can help me troubleshoot this it would be greatly appreciated, because I am stuck! Thanks all!!

 

[J-T]

Did you replace the brake shoes?

 

[Mischiefbrewer]

I have not

 

[Mischiefbrewer]

Replaced the shoes, still the same problem... any other advice?

 

[J-T]

Ensure that each of the components is operating properly. The cable must move freely in the housing. The cam(s) must rotate freely. The adjustments must be correct.

Do you have the Factory Service Manual?

 

[longdistancerider]

Sand the drum with coarse sandpaper and brake clean, not carb spray. Sand the shoes also.
When installing the wheel be sure the brakes are applied while tightening the axle nut and cap.
Adjust the center link so there is zero freeplay and both arms move at the same time.
Now roadtest slowly and apply the brake several times.
Disassemble and see what the contact patch on each shoe looks like, you might have mis-arced shoes which only allow partial contact.