AC Brake Adjustment

[Al Meadows]

While preparing to return home from a local tour I noticed my right side AC brake assembly hanging down, swinging in the breeze. With a few parts missing, I tied it up out of the way and continued home without incident using the remaining left brake and transmission brake.

Today I'm under the car with the brake reassembled but questioning whether or not it's functioning properly. With the wheel turning freely and the brake rods disconnected, I pull on the actuating arm as if stepping on the brake pedal. The lower band never really tightens up on the lower portion of the drum except right at the front . The top band tightens uniformily around the upper part of the drum making it very difficult for me to turn the wheel but I'm still able to a move it a little. If I tighten the adjustment one more click I can definately stop the wheel but now there is noticeable drag upon releasing the arm. I have no one else to push the pedal while I turn the rear wheel at the same time so I do all this while lying under the car with both rear wheels up on jack stands

As I remember, upon activation these brakes sort of wrapped around the drum and it might be difficult for me to adjust them as I'm doing. Also maybe when hooked up to the rods and a pedal perhaps there will be more force applied. I thought I would throw this out to the group asking for adjustment tips and clarification as to its operation before my next step: hook up the pedal, pick an adjustment and drive. Check braking, excess heat at drum, re-adjust, repeat. All while keeping my transmission brake functional.

Al

[Mark Gregush]

Your leg muscles are going to put a lot more force on the lever then your hand/arm can. From the post in back over the top, is self-energizing going forward and from the post under the lining is self-energizing in reverse when the lever is pulled. The adjustment does not sound too bad at this point. I would drive and test. If one side or other band/drum is getting too hot that side needs to be backed off a little.

[Al Meadows]

Thanks, Mark, for the encouraging words. I installed these myself a few years ago and they worked fine after a few adjustments. They performed so well in fact that after about 100 miles my rear spokes started making noise. Turns out that because my primary braking power was now grabbing the brake drums instead of slowing the axle, it loosened up my hub bolts. I had peened them 50 years ago with no issues but the outside brake operation loosened them. I restaked them with prejudice and that problem has not resurfaced.

If there is no secret way to adjust before flight, then I will proceed just as you said.

Al

[speedytinc]

Thanks, Mark, for the encouraging words. I installed these myself a few years ago and they worked fine after a few adjustments. They performed so well in fact that after about 100 miles my rear spokes started making noise. Turns out that because my primary braking power was now grabbing the brake drums instead of slowing the axle, it loosened up my hub bolts. I had peened them 50 years ago with no issues but the outside brake operation loosened them. I restaked them with prejudice and that problem has not resurfaced.

If there is no secret way to adjust before flight, then I will proceed just as you said.

Al

I have my period small drum accessory brakes adjusted to come on just after the transmission brake.
You might consider adjusting the two brake systems to work together also.

[Al Meadows]

John - I have them working in tandem. Honestly, it was the only way it seemed possible with one pedal, in theory anyway. I've read from others how they have set up their brakes to work the transmission brake first, followed by their preferred auxillary brakes or vice versa. I may be interpreting this incorrectly but, in my mind, once one braking method is fully engaged, how can you press the pedal down further to activate the secondary system? So I imagine everyone uses this "combo" system whereby initiating one braking system part way is followed by the seconday system adding additional stopping power. Which one is used first and at what point the secondary sytem joins in for full braking is a personal preference.

I did ride with a guy who had his RM brakes independently tied to a brake handle he pulled when stopping. Worked great but I prefer a more simple operation, especially in a panic situation.

This is all floating around in my head, John.

[Mark Gregush]

"I did ride with a guy who had his RM brakes independently tied to a brake handle he pulled when stopping. Worked great but I prefer a more simple operation, especially in a panic situation."

While some still do have it set up that way, back in the day when people were doing it, there was not as much traffic. Got enough to do driving to have to reach down and grab the parking brake handle at any time panic or not.