Topic: Rear Brake Seized!

[brandon]

The bike is a 75' 400Four with a rear drum brake. I searched the FAQ as well as the archives and came up with nothing. In a nut shell, the starting mechanism is applying leverage on the rear brake pedal which in turn, turns a splined cylinder in a housing that has a rod connected to the opposite side of it that turns another mechanism in the brake housing.

My problem starts at step one. The splined cylinder that the brake pedal attaches to is rock solid, not moving/spinning at all. I pulled the rear wheel this morning to get a closer inspection of what was going on. I attempted to tap the cylinder out of the housing with a hammer. No dice. I inspected the spring that returns the pedal back to position, and it was fine. I inspected the rods that connect to the brake housing. Those were fine. I inspected the rear brakes, those were fine.

I am unsure where to start, or even if this cylinder is removable for inspection at all? Granted it's the rear brake and not as important as the front, but it's a stopping mechanism none the less.

Any helpful insight is greatly appreciated. Thanks for reading.

Brandon

[bryanj]

Sound like the link has siezed in the frame,
Liberal application of easing oil with use of a hammer and if that dont work heat and a hammer

[steam-powered man]

take a look at these parts in an exploded view at bikebandit.com, can be very helpful.  it shows the splined rod you are talking about, and how it's mounted in the frame. 
bobp

[KB02]

Sounds like the same issues that I had with the old KZ550 I just sold. The rear brake was practically frozen solid. I thought that I was in for a whole bunch of parts sourcing and improvising. Turns out all I needed to do was take it apart and lube it all up.

[dagersh]

I agree Brando - I have a '76 Wing that had the same symptoms.  With the lliberal use of heat and penetrating lube i was able to disassemble the frozen rear brake linkage, lube everyting and then reassemble.  Worked like a charm, and I have had no problems since.

Let us know how you make out.

gersh

[brandon]

Thanks for the help. I had the opportunity today to get to work on this issue. The bike had no brakes at all. I started with bleeding the front brake. I bled a whole small container of brake fluid through the system, getting all the bubble out. I go to sqeeze the handle: No dice. Pads do not grip the rotor. I'm not sure if the problem is in the Master Cylinder or the Caliper. Regardless, perhaps it's time to replace it?

The rear brake is now functioning properly. Like butter. This went a lot easier than I was expecting. I sprayed WD-40 on the rotating shaft that the brake pedal connects too, to let it penetrate over night. Took the rear wheel off along with the right peg, brake pedal and brake rod. Tapped out the splined shaft with a 5lb sledge.

The shaft was gunked up something fierce. The gunk was almost like concrete. I got it all off and polished the shaft with emery paper and did the same to the housing for the shaft. I used some gnarly axle greese and assembled everything. It works better than it ever has.