Topic: Where can I find more info on CB500 rear brake issues?

[pookie]

Long version-
I've searched every term I can think of dealing with the rear brake shoe/drum.  I've looked at the workshop manual, as well as other build threads.  But I don't see anyone describing/dealing with the same issue I am looking at.  My rear brake pedal will travel a good 6-7" below the foot rest.  My lever travels all the way down, scraps the exhaust, and only stops when it cannot possibly go any further.  Essentially I have no rear brake at all.  Granted I'm not riding it yet, but I thought I would work on fixing the brakes while I searched for some other parts I need.  I've tried the adjusting screw, and the bolt (incidentally I learned that my bolt is installed upside down)  and short of pulling off the wheel and checking the shoe/drum, I'm not sure what to do.  I read that the lever could be a couple splines off, but none of the posts, and the manual never mention how to count the splines or tell if they are off. How do I tell if it is the splines? 

Short version-
I need some more detail on the rear brake/shoe combination, as mine isn't working right now.
 

[MoMo]

First off, I'd pull the rear wheel to make sure the brake shoes are in decent condition.  If they are, I'd then relocate the brake arm on the splined shaft...larry

[mrfish2]

First off, I'd pull the rear wheel

+1

Sounds like you don't have any pads left, definitely pull that wheel off and see what's going on.

[Don R]

X3, I've seen the lining come completely off the shoes, pull the wheel check it out. Get new shoes if needed. Clean and scuff the drum. Sit and study the levers and linkage, adjust it.

[Stev-o]

You obviously have a brake issue that requires removal of the rear wheel to properly inspect it.
Why the hesitation to remove it? It's not very difficult, especially if you have a center stand.

[pookie]

Thanks guys.

I'll get the wheel off tonight.

Also, I'd be lying if I said I didn't have slight hesitation on removing the rear wheel.  Actually my hesitation isn't with removing, it's more a fear of a being able to get it back on and everything lined correctly afterwards, because I have never had to do that before.  But in only my first couple of posts I've learned that if I can't figure it out you guys are here to help.

Calj737- thanks for the link, that is one I found before posting and saved for future reference...

[Stev-o]

Thanks guys.



Also, I'd be lying if I said I didn't have slight hesitation on removing the rear wheel.  Actually my hesitation isn't with removing, it's more a fear of a being able to get it back on and everything lined correctly afterwards...

Here are 2 suggestions to help you in the future with such tasks:

1. Take many photos of the assemblies before and as you take them apart.

2. Get a manual and read it before and during the service work you are performing.

Your hesitation is typical from someone who hasnt repaired brakes before. I guarantee once you've done it, you will think "that wasnt so difficult". These bikes are easy to work on, unlike modern cars.

And yes, we are here to help.

[pookie]

Rear wheel is off.  I didn't dive into the brakes yet, cause I got tired.  But I'm sure I will have some questions later tonight. 

[mrfish2]

Post up some pics, I'm curious as to what's going on in there.

[strynboen]

here is a Photo, of how  bad brake drum can go...rust and korosion have broken the casting total..
hope yours is better looking

[pookie]

After pulling the wheel everything just slid out of of the hub, I did not have to pull or pry anything to get the rear brake panel off.  Are the shoes supposed to have some slight drag, or at least be touching the drum?  Here are some pre cleanup pics of what I have going on: 

[MoMo]

shoes look usable, can you post a close up photo of how the actuating arm is located on the shaft?

[BomberMann650]

Gotta love the simple elegance of the cb's rear brake.
shoes mount to a big plate, steel bar from chassis  holds plate still, steel rod from brake pedal engages brake.  long story short.

only considerations on reinstall is to make sure the rear sprocket sits well within the chain links and that the adjusting nut on the brake pedal rod is in spec.

[pookie]

I have the ones I took for reference when I put it back together.  Like the one below.  I can get straight on pic tonight. 

[mrfish2]

Have you tried adjusting the actuating arm (via the nut on the threaded rod behind the spring) to take the slack out of the pedal?

[pookie]

Have you tried adjusting the actuating arm (via the nut on the threaded rod behind the spring) to take the slack out of the pedal?

Yes.  All the way in and all the way out, neither made a difference.  I can push the pedal down so far that it scrapes the exhaust? 

With that said, with it disconnected, I can push the actuating arm and it engages the shoes and grabs the drum just fine. 

[Duanob]

Move the actuating arm on the brake drum by hand, there should only be maybe a 1/2" of travel at the most. If there is more then something inside the wheel isn't installed correctly or the spline shaft is stripped. If there isn't more than 1/2" of travel then something else in the linkage isn't installed correctly.

[Deltarider]

When I look closely at that photo, I can see that the two little round marks (one on the actuating arm and one on the cam) are not properly aligned. They should.

[seanbarney41]

When I look closely at that photo, I can see that the two little round marks (one on the actuating arm and one on the cam) are not properly aligned. They should.

Delta's got it...you gotta line up the dots.  You can even advance them if your shoes are worn, in a pinch.

[Restoration Fan]

Did you take photos of the other end of the brake arm?  Specifically, I'm asking if the vertical arm that's on the inside of the brake pedal rod was facing up or down?  It should be sticking up and not down.  Otherwise, when you press on the brake, it won't activate the brake drums.

[przjohn]

When I look closely at that photo, I can see that the two little round marks (one on the actuating arm and one on the cam) are not properly aligned. They should.

Delta's got it...you gotta line up the dots.  You can even advance them if your shoes are worn, in a pinch.

THIS

[pookie]

So the actuating arm needs to come off and be rotated clockwise to make the dots line up?

Thanks

[pookie]

I have brakes!!!!! 

Got the dots lined up and everything reinstalled.  Brakes work. I find adjusted them according to Cals link, and the manual linked from this site, and they are sweeeeeeeeeet!

Thanks to all

[Restoration Fan]

Great news, pookie!

Way to persevere and get the problem solved!