Topic: Rear brake very weak

[shouse76cb]

Hi all

I replaced my aftermarket brake shoes with Honda ones. I noticed only about half the aftermarket shoe was contacting the drum. I read that the Honda ones are radiused better to the shape of the drum as I took this for the reason by rear brake was weak. I took care to clean the brake plate and drum and not to contaminate the new brake shoes. I put it all together and went for a ride....now the brake is weaker than before! Everything is adjusted correctly and all my dots are lined up. Do they just need some "bed in" time or did I miss something? Thanks for any help

[MCRider]

Hi all

I replaced my aftermarket brake shoes with Honda ones. I noticed only about half the aftermarket shoe was contacting the drum. I read that the Honda ones are radiused better to the shape of the drum as I took this for the reason by rear brake was weak. I took care to clean the brake plate and drum and not to contaminate the new brake shoes. I put it all together and went for a ride....now the brake is weaker than before! Everything is adjusted correctly and all my dots are lined up. Do they just need some "bed in" time or did I miss something? Thanks for any help

Yes they do need to bed in. Put them through some hard heat cycles without overheating.  But try this.

Loosen the axle nut (On CenterStand). Activate the brake by having someone stand on it or crank the adjuster nut in till tight. This will center the brake plate into the drum, making as much shoe contact as possible. Tighten down the axle nut. Now loosen the brake.

Try it and let us know.

RaceTec "arcs" brake shoes to the drum (for $200) and this is what they say to do on assembly.

[shouse76cb]

Thanks for the reply MC...I'll try that tomorrow and report back on the results. I'll also put it through some heat cycles to help it bed in. Thanks also for the frame bracing pics you posted on my other thread

[CycleRanger]

You might take a little emery cloth on the inside of the hub to scuff it up a bit to deglaze it.

[bollingball]

Hi all

I replaced my aftermarket brake shoes with Honda ones. I noticed only about half the aftermarket shoe was contacting the drum. I read that the Honda ones are radiused better to the shape of the drum as I took this for the reason by rear brake was weak. I took care to clean the brake plate and drum and not to contaminate the new brake shoes. I put it all together and went for a ride....now the brake is weaker than before! Everything is adjusted correctly and all my dots are lined up. Do they just need some "bed in" time or did I miss something? Thanks for any help

Yes they do need to bed in. Put them through some hard heat cycles without overheating.  But try this.

Loosen the axle nut (On CenterStand). Activate the brake by having someone stand on it or crank the adjuster nut in till tight. This will center the brake plate into the drum, making as much shoe contact as possible. Tighten down the axle nut. Now loosen the brake.

Try it and let us know.

RaceTec "arcs" brake shoes to the drum (for $200) and this is what they say to do on assembly.

+10

[Bodi]

This situation is pretty normal. The advice to align the shoes is good. But for proper performance, replacmenet brake shoes need to be radiused to match the drum diameter. I learned to do this in high school auto shop 40+ years ago, you set the desired radius on a machine that amounts to a complicated sander then take off friction material from the shoe until it's a smooth curve. Since disc brakes took over, the skill and machinery to do this have pretty much disappeared. If you find a brake shop that's been in business a long time they might still have the machine under a few inches of dust, and even someone who can use it. Truck brake shops do this all the time but their machines are way too big to fit a bike shoe.

[trueblue]

This situation is pretty normal. The advice to align the shoes is good. But for proper performance, replacmenet brake shoes need to be radiused to match the drum diameter. I learned to do this in high school auto shop 40+ years ago, you set the desired radius on a machine that amounts to a complicated sander then take off friction material from the shoe until it's a smooth curve. Since disc brakes took over, the skill and machinery to do this have pretty much disappeared. If you find a brake shop that's been in business a long time they might still have the machine under a few inches of dust, and even someone who can use it. Truck brake shops do this all the time but their machines are way too big to fit a bike shoe.

We have one of these machines where I work, but to be honest I haven't seen it used in over 3 years, and it's been even longer since I used one.

[MCRider]

As their piece says they were talked into offering the service again. I shipped my wheel, as it must be laced up, to CA and got it back in about 10 days incl shipping. I can't remember where i discovered this service, probably someone else on the forum. Haven't ridden the bike yet to report. They had to remove quite alot of material to get them to match up, indicating the shoes just aren't very good.

I sent them SBS shoes (Scandinavian Braking Systems)

http://www.racetech.com/page/title/Brake%20Arcing

I suspect the heightened interest in vintage racing provides a market for the service. Just imagine one of those old 4LS brakes set up properly...

[shouse76cb]

Well I loosened the axle nut and centered the shoe on the drum as suggested. Tightened everything up and went for a ride. After putting the brake through several heat cycles to try and bed them...they are performing much better than before. I'll have to save up for the Racetec work as it will come after I add a second disc to the front. MC..let us know how that rear drum feels when you can. It's funny that years ago I was more interested in going faster...now I'm trying to stop quicker Lol

[MCRider]

Well I loosened the axle nut and centered the shoe on the drum as suggested. Tightened everything up and went for a ride. After putting the brake through several heat cycles to try and bed them...they are performing much better than before. I'll have to save up for the Racetec work as it will come after I add a second disc to the front. MC..let us know how that rear drum feels when you can. It's funny that years ago I was more interested in going faster...now I'm trying to stop quicker Lol

And keep in mind, AIYDK, the rear is only good for 20% of the total braking. You should rely on the front for the lion's share.
If you're wanting the rear to do more, it simply can't. Weight transfer to the front alone pretty well knocks out the rear, causing it to lock up, which is the worst condition.