Boxerworks.com

Duane Ausherman wrote:When sanding a glazed shoe, it is often done incorrectly. It seems natural to hold the shoe in one hand and sand with the paper in the other hand. Nope, that doesn't work well at all.

Lay the paper on your flat glass plate. Now, rub the shoe against the paper in an even sweeping motion. This does the job better and faster than the former way.

Easier to stay square, too.

I took the rear wheel off again and examined the brakes. There seemed to be wear on most of the brake shoe surface.

What I did notice is that the travel of the brake pedal (2 or 3 inches until the pedal contacts the exhaust pipe) results in 2-4 millimeters of shoe expansion when the brake cam rotates. So it is only on the last 1/2 inch of pedal travel that stopping pressure is exerted on the brake drum. With the pedal disconnected, I can push the brake lever on the drum and get a bit more expansion of the shoes. But the additional expansion is not possible using the pedal because the pedal impacts the exhaust pipe. I really would rather have only 2 inches of brake pedal travel.

I do have the brake lever adjusted as Duane recommends at a slightly less than 90 degrees before the brake pedal is pressed.

Maybe I just need to wait for the shoes to bed in.
Thank you.
George

When I used to work on cars when only drum brakes were made, it was a common procedure to arc the shoes to fit the drum. There were even attachments to grind the leading and trailing edge of the brake material to grind down the high spot. If you examine your old shoe you will see that the thickness of the brake material is thinner in the leading and trailing edge of the brake material, fatter in the center. If it was me I would just not worry about it too much, after some use and miles they will bed in and braking will be normal. If you want to speed up the process, just increase the drag and it will speed up the process of forming the shoe.

gg

George inMinneapolis wrote:I took the rear wheel off again and examined the brakes. There seemed to be wear on most of the brake shoe surface.

I do have the brake lever adjusted as Duane recommends at a slightly less than 90 degrees before the brake pedal is pressed.

Maybe I just need to wait for the shoes to bed in.
Thank you.
George

Maybe I'm reading this wrong and don't understand what you are saying. Duane recommends 90 degrees before you hit the brake. But that's AFTER you take all the slop out of the pedal travel. George you should not need to depress the pedal two to three inches. Your brake should be solid BEFORE it comes near the muffler. Is this your situation? If you are getting wear on most of the brake shoe, a little more pressure should lock up the wheel.

daz wrote:
Maybe I'm reading this wrong and don't understand what you are saying. Duane recommends 90 degrees before you hit the brake. But that's AFTER you take all the slop out of the pedal travel. George you should not need to depress the pedal two to three inches. Your brake should be solid BEFORE it comes near the muffler. Is this your situation? If you are getting wear on most of the brake shoe, a little more pressure should lock up the wheel.

Yeah, this is starting to confuse me too. If I understand George correctly, he is setting his brake adjustment so that it is just starting to drag on the drum before he touches the brake, but he's having to press the pedal 2-3 inches to get real braking.

George, if this is what is actually happening, then there's something really wrong.

The linkage just barely after the rear brake lever can be assembled incorrectly and do exactly what you report. I can't remember if I documented this on my article or not. One of those bits gets flipped over the wrong way. It still sort of works, but not as designed. It is the casting with the two arms that are about 90 degrees apart that gets flipped.

Duane Ausherman wrote:The linkage just barely after the rear brake lever can be assembled incorrectly and do exactly what you report. I can't remember if I documented this on my article or not. One of those bits gets flipped over the wrong way. It still sort of works, but not as designed. It is the casting with the two arms that are about 90 degrees apart that gets flipped.

AHA!

On my bikes, there is a pivot for the brake pedal arm. There is an extension that sticks up. The extension has a bolt for actuating the brake light switch - that part is adjustable. The brake rod is attached directly to the part that I'm calling an extension (extends upward). There is no part that I would see as "linkage". My oldest bike is 1974.

Is there a linkage I'm not remembering, or seeing, or understanding?

Chuey

Well, Chuey, everything between the brake pedal and the brake cam shaft is linkage, including the rear arm, but I don't see how the R80 brake linkage could be assembled backwards.




On a lighter note, no wonder Duane thinks those snowflakes are too heavy. Check out the title of the snowflake fiche (the title doesn't show if I link the image, so you have to go to the site:
http://www.maxbmwmotorcycles.com/fiche/ ... d=04282014

OK, if we are going to call it linkage, I'll go along with there not being anything to get wrong. So, I think you understood my point. I have seen the hole the pin goes through to hold on the rod become somewhat oblong.

All my rear brakes are dismal except for the RT with a disc. I bought that one to try for a 1,000 mile day. First day I rode it, it was 800miles home frin Oregon (saw Duane on the freeway) and haven't ridden it since that day except to test it when I fixed the front brakes.

Where does #22 go? I can't place that part?

Chuey