Topic: Can you lock up the rear brake on a 550?

[denward17]

My '76 550K, I installed new shoes a while back (Dennis Kirk - EBC).

I thought they would "break in" a little and get better, but after 1500 miles or so, they haven't.

They feel mushy, so to speak, I cannot lock up the rear wheel.

What problem do you think I have?  Am I expecting too much?

Are you able to?

[Deltarider]

In emergency stops I'm able to lock the rear brake and leave a nice print on the turmac. Bike is a CB500 with still the same shoes bike got at the assembly line in 1976. IMO it has to do with the angle 'of attack' by the lever.

[Don R]

 My 500 could. You don't want to, but it is a sign the rear brake isn't optimal.

[BallAquatics]

With Dunlop Trail Max tires, my 74 550 sounds like a dump truck when the back tire locks up!!!  Maybe tighten up your adjuster?

[Ozzybud]

My 1975 550K1 will lock up.

It sounds like your Hub/Shoes are glazed.

[denward17]

OK, Thanks guys, something to do this winter.....

[Ozzybud]

These 220 grit flapper wheels work great to clean up hubs

[Flyin900]

Check the arc of the shoes on your drum. If you have put that amount of mileage on them you should easily be able to see the contact patch area. It could be your not getting proper brake shoe contact area on the drum.

[denward17]

All good points, Thanks.

[kyle750]

I  installed new brake shoes in my CB550 about 2 months ago with a replacement brake plate.  Sanded the interior of the inner hub drum walls very well and installed NOS Honda brake shoes with new grease on all the pivots. Braking is quick, responsive, and very powerful stopping action. Not road tested yet! 

[bryanj]

You should be aplying the brake hard before and whilst tightening the spindle locknut, it centres the shoes. Honda tolerances are good but a small amount makes a difference.
Does it feel like the pedal is pulsing up and down? If so the drum is probably cracked

[denward17]

You should be aplying the brake hard before and whilst tightening the spindle locknut, it centres the shoes. Honda tolerances are good but a small amount makes a difference.
Does it feel like the pedal is pulsing up and down? If so the drum is probably cracked

No it doesn't pulse, I just have to press down hard and its like I'm not pressing it hardly at all.  It works good on the center stand, as I want it to spin freely by hand and it grabs good when I spin it and hit the brake pedal.

What do you mean by "You should be applying the brake hard before and whilst tightening the spindle locknut, it centres the shoes"

Maybe I haven't adjusted correctly because my adjustment is at the end of the spindle now and if I go tighter the wheel will not spin freely by hand while on the center stand?

[bryanj]

Sorry cant think of any other way to say it

[Don R]

 Loosen the axle nut, apply the brake and then tighten the axle nut while pressing the brake pedal. It might not matter, but it might.

[Deltarider]

Loosen the axle nut, apply the brake and then tighten the axle nut while pressing the brake pedal. It might not matter, but it might.

Then you run the risk, the axle nut will not go all the way it needs to go and that you end up with play of the rear wheel...

[bryanj]

No you dont, the nut still tightenes the axle completely, just the radial position of the brake plate in relation to drum alters

[Don R]

 Did you compare the arc of the shoes to the inner diameter of the drum? It's possible they are only contacting each other on the ends or in the middle.
  I've heard of arcing shoes but I don't know how it was done, maybe by bending the backing plate or sanding the friction material?

[Kelly E]

The old guys used to sand them on the belt sander. They did eyeball calibration by holding them in the drum and check out the fit.

[dave500]

I had some cheap rear shoes once and had the same as you,I could actually stand on the pedal and it would not lock and only slowed the bike slightlyI bought genuine honda shoes and it worked brilliantly after that,once those wore out Im using ferodo now and they are fine,cheap shoes are rubbish

[Bodi]

I've owned a few older bikes and ridden a lot of them. They could all lock the rear wheel and doing so on purpose to make a loud squealing sound that got more attention than the little meep of the horn was common.
The local repair garage probably had a brake shoe radius machine back before cars had disc brakes. Replacing the shoes meant measuring the drum diameter (they wear too) and setting that measurement on the machine. It ground the brake shoes (with lots of asbestos dust of course...) to match the drum.
I have put some marker on the drum, installed the brake (yes push the pedal while tightening the axle) then turn the wheel while applying the brake (lightly so the wheel turns). Remove the brake and see where marker has transferred to the shoes. Usually the shoe is a bit small (contact only in the centre). Some medium grit sandpaper glued or taped on a flat surface and a bit of elbow grease - over a few iterations - should get the shoe pretty close to full contact. Does not have to be perfect but getting most touching will be a big improvement.
Or find one of those machines rusting in a dusty corner of an old repair garage somewhere... if any still exist that haven't been turned into convenience stores.
Truck repair shops still have them but our tiny shoes won't fit on a machine made for huge truck brakes.

[kyle750]

I bought NOS brake shoes on ebay.  I made an offer which the seller quickly accepted.  I re-used the springs from my old shoes.  Brakes installed with no issues. Not road tested yet but up on the stand the new shoes worked well and stopped the wheel with solid and responsive braking.  Traveling at high speed with my fat ass on the seat will be the real test 

https://www.ebay.com/itm/204174250652