Page 1 of 1

How do I balance brakes?

Posted: Fri Feb 25, 2022 6:49 am
by rainer
Hello.
Last sunday I started my Lizzy first time this year. It still is sitting on four support frames, so all four wheels are a little bit above garage floor.
The engine started surprisingly easy. On 2nd try the engine started, but stalled, on 3rd try it was running smoothly.
The handbrake lever was in back position, but the left wheel was still running, while the right wheel was standing still... Then I used some more force on handbrake lever and got one more "click", then the left wheel was also standing still.

--> So the parking brake is not balanced well.

I shortened the left pulling rod by one turn of the clevis, but I didn't try again (it only can have become better, but I have no idea about how much better). Reason: Even with good ventilation of my garage the CO meter shows very quickly 600-800 ppm and I am not willing to get poisoned. Later I will do some fine tuning when my Lizzy is parked outdoors on the street.

How do you adjust brakes?

I have following brakes installed:
  1. Parking brakes (of course)
  2. Inner band brake (of course), with good lining.
  3. A.C. Brakes.
    They are a little smaller than Rocky Mountain brakes and work on the outside of rear parking brake drums, having a band divided into two halves with linings. This brakes have separate pulling rods to another axle mounted closely behind the engine to the frame. This brakes are coupled to the brake pedal, so when pressing the pedal, the brake band inside the gearbox and rear AC brakes work simultaneously.
Especially the driving brakes appear a bit difficulty to adjust.

My idea for adjusting the parking brake is:
Pull the braking lever only to the point where I can still rotate both wheels by hands (with as much force I can apply with my hands). Then I shorten the easier turning wheel's rod by turning the clevis bit by bit until both wheels are needing almost the same force.

For A.C. Brakes it is more complicated.
There is one band brake in the engine (working on both rear wheels through the differential) and two individual brakes on the wheels. To get most efficiency I want to involve the front band brake, too. But how to find the sweet spot between this three brakes?

After re-inserting the engine (it was pulled for replacing the clutches), I set the internal brake to that point where the pedal stops 2" before the end of the related floor board slot. Then I connected the clevis of A.C. brakes to the pedal again. From my last test drive - yes, I could brake, but it was not very strong. So I am not sure if this was primarily the braking band or A.C. Brakes.

An suggestions are welcome.

Rainer

Re: How do I balance brakes?

Posted: Fri Feb 25, 2022 8:20 am
by DanTreace
Your methods are the way to adjust. Sometimes it takes a couple tries.

For the emergency/parking brakes, do like the Service Manual states @ para. 75, on jack stands, rear end up off ground, you can’t set these parking brakes with the drive line in power, they can’t stop with the T in gear.

Normally set the hand lever in ‘neutral’ or whatever near vertical your hand lever is normally in neutral. Then I pull each rod forward until the brake cam lever has slightly engaged and expanded the brake shoes , by noting very slight resistance on the wheel as you one hand turn it. Then, while pulling with same tension on the rod, the brake rod clevis is turned and lined up with the handbrake yoke. Final test by pulling back the hand lever, to its rearward position, and testing each wheel by strong pull with both hands to feel each is solidly locked up. Adjust individual rod if one wheel still can move with the hand lever still in its rearward position.

As for your accessory outside brakes, mine adjust so they engage first, about 2 inches or so of forward brake pedal push, then the transmission brake is engaging after that travel, so both can work. Floorboard measures vary, so I use horizontal travel of the brake pedal to measure. My brake pedal sets 6” up, 2 inches of travel and the outside brakes engage, the trans brake at about another 2 inches, and fully pushed brake pedal firmly stomped down, about 1” off the floorboard.

Road testing is required , so some adjustments are needed and from time to time with wear of the outside brake linings. To have the external engage first, the linings are set real close to the drum. Initial setting is done by short stops and runs, then feeling each drum for excess heat. If one is hotter, back off on adjustment at the external shoes.

Majority of stopping is with the outside accessory brakes, of course you close throttle first and let the T slow itself down before applying the foot brake in typical driving. But fast stops can be done, after closing throttle, and can lock up the rear wheels if needed.

Re: How do I balance brakes?

Posted: Fri Feb 25, 2022 10:50 am
by rainer
Thanks for this detailled description.

VERY helpful. I will read the service manual this weekend.

Re: How do I balance brakes?

Posted: Fri Feb 25, 2022 11:39 am
by halftracknut
Thanks for the great refresher....going to go check mine right away....