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Discussion Starter #1
Broke into the rear brake assembly yesterday, and posted pics (Gallery under my name) of what I found. LOTS of earth tones - cleaned up with CRC cleaner (yikes that stuff's toxic!), but can anyone tell me what's breaking down to create that color? The pads have a little life left in them, but I'm pretty sure the drum is shot. Do I have to replace the entire rear wheel? <sigh>

Happy Thanksgiving, everyone!!
 

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and the Adventure Cycle
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The color you see is most likely just brake dust. I wouldn't worry too much about that.
As far as the drum, what size did you get when you measured it ?
7.086" - 7.093" is standard size. 7.116" is the recommended service limit, but you could go a little beyond that (with fresh pads)
 

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Discussion Starter #3
Ummmm...I didn't measure the drum itself. Somehow that didn't dawn on me. But the rear of the bike is still totally disassembled ('cept I put the wheel back on after I lubed the splines), so I can check it in the a.m. Is it possible for the drum to just warp, though?
 

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Crobins365 said:
Ummmm...I didn't measure the drum itself. Somehow that didn't dawn on me. But the rear of the bike is still totally disassembled ('cept I put the wheel back on after I lubed the splines), so I can check it in the a.m. Is it possible for the drum to just warp, though?
Cindy -

I doubt that the drum can warp as it is part of the wheel center and lots stronger than a regular drum brake.

From the pictures, looks like brake dust residue.

Clean it good with brake cleen and check as Hyper said above, if within spec, throw in some new shoes and adjust the linkage.

Should be good to go.

I honestly use my rear brake very little as the front is pretty stout, especially after the stainless lines went on. Mostly just use the rear to hold on a hill when stopped.

Jon
 

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Geek
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Took a look at the shoes. From what I can tell they look like they have plenty of meat left. I think if you just clean everything up they would be good.
 

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Discussion Starter #6 (Edited)
I thought they looked okay, too, but what concerned me was the gap between the drum and the final drive and the brake side. I added a pic to my "rear brake" album (http://www.vn750.com/photopost/useralbums.php)
...hmmm. That link may not work. Okay, now i think I attached a pic to this message, but that may not have happened, either. Anyway, there's a small gap (2 mm) between the drum and the final drive, and a 1mm gap between the drum and the brake cover. That's what's making me think that there's a problem with the wheel overall - it's just not a very snug fit. So it may actually not be a problem with the brakes or the drum, but something else? Or maybe a gap like that isn't to be fretted about? I dunno - maybe my tolerances are lower than Kaw's.
 

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Search Goddess
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Yes there is a small gap on both sides of the wheel, the final drive side a little more than the brake side. You have a real good example of this on your running bike. I think if you compare the two assembled you will see that they are about the same.
One note, if you by chance left one of the collars out or the large o-ring and tightened the wheel down, chances are it would lock up on you and not spin freely
 

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Discussion Starter #8
Dianna said:
Yes there is a small gap on both sides of the wheel, the final drive side a little more than the brake side. You have a real good example of this on your running bike. I think if you compare the two assembled you will see that they are about the same.
One note, if you by chance left one of the collars out or the large o-ring and tightened the wheel down, chances are it would lock up on you and not spin freely
You're right...although for some reason it looks like less of a gap on the drive side of my running bike. Hmmm. As for a missing collar, I checked the shaft before I put the wheel on (it spun) and checked it again after I put the wheel on (it spun, too). I'll keep mucking around with it - I still don't like the way the drum cover sits on the wheel (maybe that's warped??), but I could be looking for a problem where there's not one. It's just, ya know, the brakes...! :)
 

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Crobins365 said:
You're right...although for some reason it looks like less of a gap on the drive side of my running bike. Hmmm. As for a missing collar, I checked the shaft before I put the wheel on (it spun) and checked it again after I put the wheel on (it spun, too). I'll keep mucking around with it - I still don't like the way the drum cover sits on the wheel (maybe that's warped??), but I could be looking for a problem where there's not one. It's just, ya know, the brakes...! :)
But it is only your rear brake, which like I said, I rarely use. The fronts provide probably 90% of the stopping power on these bikes used correctly.

Just make sure that mechanically all else is right.

Jon
 

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Discussion Starter #10
I actually use my rear brake consistently, tho' I know that 3/4 of the stopping power comes from the front. But given the bike's weight, if I only use the front brake, I end up getting tossed forward a bit too much from momentum. I find I come to a more balanced halt with a steady rear brake application... and lord knows that some percentage of riding is looking good doin' it! :)
 

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Just ride so your comfortable. Everyone does things a little differently.
 

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Crobins365 said:
I actually use my rear brake consistently, tho' I know that 3/4 of the stopping power comes from the front. But given the bike's weight, if I only use the front brake, I end up getting tossed forward a bit too much from momentum. I find I come to a more balanced halt with a steady rear brake application... and lord knows that some percentage of riding is looking good doin' it! :)
Then don't stop (no pun intended), get that rear brake correctly sorted out and ride on!

Jon
 

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Looking at your attached pic, I don't see anything wrong. There has to be a gap there for the wheel to turn. If there wasn't one, the wheel would rub against the stationary outer hub and that would be worse. 2mm sounds about right. Mine looks similar.
Your brake shoes look just fine. As for all the colors, brake shoes and pads are not made of just one material, they are a composite. As such, when heated due to friction (braking action) the shoe material wears off and the different components partially separate leaving their own particular dust. Hence the different colors. Yours looks like just about every other shoe/drum brake assembly I've ever worked on. Disk brakes do the same thing but because they are more open, more of the dust falls to the ground or is suspended in the air momentarily. Some makes its way onto the rim and that is the residue that gets hard to clean in the crevices of our wheels. BTW, regular brake cleaner works fine and will keep the dust down to a minimum so you don't have to wear a complete "salamander suit". Just don't blow it out with compressed air!!!
 
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