[Slick willie]

Hi everyone…I’m stumped on this one. Got a 1980 shovel in a rigid frame. Wagner style 3/4” bore master cylinder (has the cup and rubber coated washer) and the 58-? Drum brakes. Replaced the 1” wheel cylinder and bled. Braked better but still scary as hell. Bled again. Re adjusted the shoes (just backed off a hair from making contact). Still same thing. Thought…oh I bet the person who built the bike has it set for disc brakes. Well took the mc apart and saw it’s set up for drum brakes. Pretty nasty in there (sludge). So gonna rebuild it but not sure it’s gonna fix the issue. Has steel braided lines. No leaks. Shoes look new. New wheel cylinder. Bled and adjusted. No glazing on shoes. Axle adjusters equal on each side. Perpendicular. Am I missing something. Pedal feels good, not spongy, but very little braking power still. Any help I truly appreciate. Thanks

 

[joe49]

What brake lever are you using? If not stock post pictures with a tape measure next to it.

 

[govmule84]

Arc the shoes to the drum yet?

 

[Slick willie]

Pedal looks stock. When in resting position it does contact the cone but not having any issues with the brakes loosening up. They don’t grab. I have not arced the shoes to the drum. Good advice! Thank you. Gonna rebuild the mc anyway (so much crud in there) and arc the shoes to the drum (make sure drum isn’t out of round first) and go from there. Thanks for the help

 

[NZT100]

Make sure the brake pedal can fully return, as in the plunger for the master cylinder is able to lift off the plate in the master cylinder it presses on to apply brake pressure. If its not able to do so the brakes wont bleed properly and you'll have REALLY low brake pressure. I had this issue on my re-pop brake and it was due to a binding issue with the mechanics of the brake itself, it required removal of some material to get it to work properly.

 

[Slick willie]

Cool cool. Arced the shoes today. Getting the mc rebuild kit this wknd. Then I’ll check that pedal position. Feeling good about this. Thanks for all your help everyone

 

[Slick willie]

Make sure the brake pedal can fully return, as in the plunger for the master cylinder is able to lift off the plate in the master cylinder it presses on to apply brake pressure. If its not able to do so the brakes wont bleed properly and you'll have REALLY low brake pressure. I had this issue on my re-pop brake and it was due to a binding issue with the mechanics of the brake itself, it required removal of some material to get it to work properly.

Also curious about what material you had to remove. Did you have to remove material from the rod or remove some from the pedal? Thanks a ton

 

[Slick willie]

Alright…I arced the shoes to the drum. I rebuilt the mc. Making sure plunger can back out of the mc all the way. Bled the system. Adjusted the front and rear cams for the shoes. Stopping power not great. I did lock up the rear tire so that’s telling me it’s working but still not impressed with the stopping power. Maybe that’s as good as it gets🤷🏻‍♂️ Seems odd. But hey it’s better than it was. Thanks for everyone’s help

 

[rhysmort]

Alright…I arced the shoes to the drum. I rebuilt the mc. Making sure plunger can back out of the mc all the way. Bled the system. Adjusted the front and rear cams for the shoes. Stopping power not great. I did lock up the rear tire so that’s telling me it’s working but still not impressed with the stopping power. Maybe that’s as good as it gets🤷🏻‍♂️ Seems odd. But hey it’s better than it was. Thanks for everyone’s help

If it's locking up the rear wheel dude that's probably as good as it's going to get. As a gent who used to be on this forum told me "You ride the old big twins with your brain not your brakes, because if you run a rear only and are expecting that to get you out of a fix, you're in for a bad time" Stuck with me, as I've seen several friends and people ride too close or not read the road and lock up and snake all over the road. I have a mech drum on my knuckle, it stops okay, but I use my gears and stay well away from cars and brake early. Unfortunately they are pretty much either on or off, feathering them leads to mass fade from the heat.. If you feel it's set up the best it can be, it may be worth asking somebody who's got experience to try it and give their feedback.

 

[tzienlee]

Harley never knew how to make brakes untill they got Brembo to sort them out!
personally I ride my bikes hard & like sticky tyres & good brakes,
if i were you I'd fit discs front & rear, a Simple conversion,.. to hell with originality & looking Cool,.....
people gotta be right jerks to ride without good brakes & Tyres,
& ya dont wanna know what I think about them who are too cheap or think it's 'Cool' to not even fit front brakes,...I had a good mate get killed when some wanker without a front braake rear ended him & pushed him into traffic & got T boned .... chuck the harlyy shit away & upgrade, if not for you, but for those ya likely to crash into.... $00.02c

 

[Jim Kelly]

How did you arc the shoes? I've heard of putting adhesive-backed sandpaper on the drum and reassembling the wheel and centering the shoes. Then work wheel forward/rearward with light brake pressure applied. Take apart and clean up. I can see some benefit to this, but not too much, since the sandpaper has thickness so the radius of the arced shoe will be too small. There are no shops around me that have even heard of arcing shoes - forget about having the machine and skill to use it. There are no shops near me that can even turn drums.

Jim

 

[Slick willie]

Yeah I did arc them. Used that sand paper method. It’s my friend’s bike. He’s got an old Harley springer on there so I think we’re gonna add a front drum brake. W&W has that dual cam drum brake set up we might go with. I know it’s no disc but hopefully it should help with the overall braking power. Thanks again for sharing they’re knowledge.

 

[JasonMcElroy]

Those here that may remember me know that I go to obsessive lengths to make old equipment work better.

I have spent years messing around with HD juice drum brakes to keep my alive in NYC on old machines.

Some things I learned that may be helpful:

- Change out the rubber hoses for hard lines or quality braided hoses to give up less energy to flex. At very least, change out with quality new rubber hoses.

- Most repop brake liners commonly available are too hard and don't offer enough friction to be effective for the surface area and force used in this application. Buy soft liners from a brake and friction shop.

- Alter your brake pedal or make your own with more mechanical advantage to get more force in the system. Moving the link 1/4" will make a difference.

- Indicate the brake drum surface (you can buy a POS dial that is accurate enough for this purpose for $20. No excused. Valuable tool) to ensure concentricity. Any out-of-round or eccentric conditions will rob energy. You can rotate the drums on the hub by one lug and retest until you find the best spot. Mark the drum and hub so you'll remember this position. If you still have runout, get the drums cut.

- Spend time setting the depth of the shoes in the drum correctly. With so many bikes (mine included) being mix of year groups and parts families, sometime the various spacers will have the shoe service not fully in the drum.

- Find an oem set of brake shoes (even if the liners are shot). The metal is thicker, stiffer, higher quality. This provide more uniform pressure at all point of the brake liner. The repop ones have too much flex.

- arching the shoes is a real thing that yields immediate results. Any shop that hasn't heard of it knows nothing about drum brake systems. Ask a brake and friction shop about how important it is and if the do it (they do).

- arching the shoes yourself is a short easy job. Here's a video of me doing mine the last time I did a rear tire change on my '58.

- clean and adjust all pivot/slide/rotation points from the lever back to the drum. Why use force overcoming linkage friction?

That's it for me. Have fun.

Jason