1977 GS550 Rear Brake Broken

[cb1ocker]

On my way into work this morning something hit the bottom of my right foot hard enough to knock it off the foot peg and brake. Didn't know what it was, but immediately noticed the back brake wasn't working when I tried to reapply it. Hobbled it into a gas station I was right next to and took a look. I'm not sure what these parts are, I'm not finding anything that looks like an exact match on any of parts diagrams I have, but it looks like maybe the cam lever broke apart from the brake drum? I can't find a before pic to compare with. I taped up everything that was dangling so I could make it to work. Anyone seen this before? Any idea what I might be looking at replacing?

[AMK]

You're missing the brace bar, torque bar or whatever you want to call it. And now it looks like you'll need the brake cam.
I looked on a parts fische and couldn't find a '77 550 with a drum brake.
I'm sure someone more knowledgeable will tune in.

[cb1ocker]

Is the brace bar the bar that I have taped to the fame in that second picture? There was a black bar that connects to the frame up near the brake pedal that was dragging on the ground. I may need to secure it all a little better with zip ties or something for the return trip

[cb1ocker]

There is also a silver bar that looks like it was responsible for pulling on the brake cam to apply pressure in the drum. that's taped up there with the cam as well. I may have all those names of things wrong. Rebuilding the rear brake was on my list of things to research and complete, guess I should have gotten to that sooner.

[AMK]

Is the brace bar the bar that I have taped to the fame in that second picture? There was a black bar that connects to the frame up near the brake pedal that was dragging on the ground. I may need to secure it all a little better with zip ties or something for the return trip

Yes thats it, I see it now.
You should get on one of your favorite parts web sites like BikeBandit or Babbits and find your bike in their parts fische. The parts may not be available through them but you can see the ones you need to find.

[dorkburger]

The torque arm (the taped up bar) bolts to the brake assembly to keep it from rotating when the brake is applied. Im guessing the bolt fell out or broke. Looks like the splined piece that sticks out from the assembly that the actuator arm connects to may have broken off as well.

[cb1ocker]

Thanks guys. After digging into it a little more it looks like that's exactly what happened. When I stopped the bike the bolt that holds the torque arm to the brake drum plate was just floating in the bolt hole. I think when the torque arm came off it got wedged in between the pavement and the rod assembly and broke the actuator off the drum plate. The bounce back of one of those is probably what I felt hit my foot. Or maybe it was the brake pedal itself when the actuator broke. I'm just glad the spring and actuator stayed together and wrapped around the axle so it didn't go into my spokes.

Next question is, does anyone know how difficult it is to replace a drum plate? From initial investigation it looks like I would take the wheel off, then maybe there are some bolts on the other side of the drum that connect the brake drum together from each side of the wheel? not sure if I have to remove the sprocket or not. I may be able to salvage the rod assembly, and the torque arm looks fine, but I definitely need a new drum plate and possibly the actuator.

[steveb922]

Schematic for the rear wheel:

https://www.cmsnl.com/suzuki-gs550-1977-b-usa-e03_model16028/partslist/BLCK0053.html#results

[cb1ocker]

Thanks Steve, I was just looking that on another site. Sounds like the wheel has to be completely torn down to get at the brake. Drum plates look like they go for 30-50 on Ebay. This seems doable. I'll post back when I get the wheel completely apart and can't figure out how to put it back together

[steveb922]

And a workshop manual that covers your model. Rear wheel detail on page 106:

http://zeus.mtsac.edu/~cliff/storage/gs/GS550_77-82_all.pdf

[Cipher]

Hey Im not the only one this happened to.
I see ebay in your future

[Rijko]

looks like a GS550B, or at least the spoke wheels.

http://www.partzilla.com/parts/search/Suzuki/Motorcycle/1977/GS550E/parts.html

you do not need to remove the sprocket.
If you take the wheel and axle out, the sprocket holder may
fall off so i usually set it aside.

The plate that is on the side you have the damage, will come out without
the need to unbolt anything.

Looks like you are lucky, not much damage.
Inspect the actuator arm for damage, it may be allright.

Think you need part nr. 4 on the image, that is what pushes the brake shoes
against the brake drum and looks like it snapped off the end which is probably
still in the actuator arm nr 20.




and the brake rod :

http://www.partzilla.com/parts/search/Suzuki/Motorcycle/1977/GS550E/REAR+BRAKE+%28GS550B/parts.html

Hopefully nothing else is damaged.

[AMK]

The Cavalry has arrived

[cb1ocker]

Thanks for all the info everyone, this actually looks like a pretty easy fix, and there seem to be plenty of parts available on ebay for not much money.

[tkent02]

I have all of that stuff, since I put disc brakes on my 550s.
Let me know.