Back brake doesnt always release.

[rainycity]

For some reason my back brake doesn`t always release like it should and it makes it tough when you have to roll it backwards. I figure I`ll take it apart and just clean up everything inside according to 5twins tutorial and hopefully that should do it.

 

[gggGary]

Do it for sure. The brake shoes are easy just "fold" them in to remove. Clean pivots, the shaft is often corroded stuck. remove buff and clean "cam" shaft and bore, degrease the fiber seal, lightly grease all contact/pivot areas with synthetic brake grease, reassemble. I like to lightly sand the drum, don't air blow the dust, not good for your lungs. Some years have a cam plate for the brake lining wear switch, it can be installed backwards but it will cause the backing plate to stick out too far. Nice rainy day project.

 

[5twins]

The grease recommended for lubing drum brake parts by 3M at Vintage Brake is Sta-Lube Premium Red grease. As luck would have it, it is available at most Harbor Freight stores .....

http://www.harborfreight.com/14-oz-sta-plex-extreme-pressure-premium-red-grease.html

 

[Marlin72xs]

Is it possible that the secondary external return spring is gone or not properly adjusted?

 

[gggGary]

The pedal pivot shaft can be corroded/stuck also.

 

[5twins]

If your 650 is an early enough model, the brake pedal pivot will have a grease fitting on it, my '78 does. I know Yamaha eliminated the fitting on later models, probably as a cost cutting measure.

 

[rainycity]

It`s an 81 and I went and got some 600 grit sandpaper and some grease and I figure a couple of hours labor and it`ll be back and running.
But then again, I may just wait until my kid gets home and make her sit down with me and watch and help. It`ll be good for her.