Topic: Rear Brake Issues

[alltherightpills]

Bike is a 78 550k

So, I got some new tires and got the rear mounted up and reinstalled and now my rear brakes don't work.  They were working fine before I took the rim off and I reinstalled everything correctly (I think) but now I can push the brake pedal all the way down and nothing happens.  I don't even hear the shoes contacting the drum.  I took the wheel back off and tried putting it back on again and had the same results.  Here is the order in which I installed the wheel:

Put the chain on the sprocket (loose)
Attach the hub stopper arm
Attach the brake rod
Move the wheel back to tighten the chain
Tighten the axle nuts

The first time I installed the wheel, I put the chain on and tightened the adjusters before I bolted the stopper arm and the brake rod on, and I pushed the pedal all the way down with nothing happened so I thought maybe I needed to attach the stopper and brake rod first.  I got the same results the second time.

It sure doesn't seem like there is a whole lot to screw up here, so what am I missing/doing wrong?  Thanks in advance...

Zach 

[martino1972]

got it figured out..

[Raul CB750K1]

1. Put chain over sprocket
2. Install wheel axle
3. Adjust chain tension
4. Tighten axle -the hub should move freely
5. Insert brake rod
6. Install torque arm.
7. With the hand, move the brake lever until it bottoms out. Adjust brake rod nut so it makes the lever rest a little bit before that point to give some play at the pedal.

[alltherightpills]

Haven't had a chance to get it figured out.  We had some friends drop in unexpectedly for a couple of nights so I've been busy hanging out with them and working.  I've been thinking about it though, and I just can't figure it.  I didn't change anything (except for the tire, obviously) so why would the shoes all of a sudden cease making contact with the drum when I step on the brake pedal.  Hopefully tomorrow I can get out there and play around with it.  Sometimes it just helps to sit and stare

[Hush]

Did you happen to reverse the actuating arm, this would make it a lot further forward and remove the ability of the brakes to be adjusted properly.
Or did you "flip" the cam? the wee actuating bit inside the hub that tilts to push the brake shoes out towards the drum?
It may only work one way round and it would have been a simple thing to have it click over the wrong way while you had the hub off.

[coyotecowboy]

If its anything like the 750 drum, flipping the cam shouldn't make any difference.  Both sides are the same.  Did you take the shoes off?  I can't quite figure out what happened in there   (not trying to sound like an ass here but) you didn't get the spring on the brake rod on the back side of the arm when you reassembled it, did you?  This is really strange

[Johnie]

OK, so when you took the tire off the bike there was no reason to remove the brake arm from the hub.  So if you did not do that the only think I can think of is did you screw the brake adjustment spring / nut to adjust the the brake pedal play?  Might be that simple as you have to unscrew that a long way to get it off.

[martino1972]

would it even be possible that he installed it inverted? like the brake lever that normally sits on top the sits on the bottom,and the brake stop lever on top??? just a thought..

[Johnie]

It should look like this pic.  Keep in mind the hub stud the brake arm sits on has a reference dimple that will align with the dimple on the arm.  Click on the pic to make it bigger.

[alltherightpills]

So I got the brake to work today, but I had to adjust everything back as far as it would go (both the nut near the spring and the stopper near the swingarm), take the brake pedal off and rotate it counterclockwise and put it back on before it would work.  Something crazy happened.  I probably need new shoes but I think they can wait until winter. 

I still can't figure out how everything got messed up so bad.  It was seriously working fine and adjusted correctly before I took the wheel off.  The only thing I can figure is maybe the PO partially turned the cam that actuates the shoes and then the attached the arm so that it wouldn't have to travel so far, but even that doesn't make a lot of sense.