Brake Adjustment

Model A Ron

Model A Ron

Well-known member
I am about to do a brake adjustment and wanted to get some opinions. What are the pros and cons of the following:

Adjusting all 4 wheels the same
Having the fronts come on first
Having the rears come on first

Thanks
 
Ron, in a nutshell you are likely an experienced driver that understands the physics involved in a panic stop. If you concur with my thoughts above, then in reality there is not an advantage of fronts, -or rears engaging first.

Some people like to argue that modern vehicle uses heavier biased front braking however if you look at the geometry of the Model-A front axle assembly, you will see that the front radius rod actually counters 'nose-dive' during heavy braking. Because of the narrow width of the tires, it is the driver that is the 'anti-lock' braking device.
 
Hydraulic braking systems were designed to have more braking on the front than the rear after the switch over to Bendix style brakes in the late 40s for Ford and Mercury vehicles. They did this by using smaller bore diameter wheel cylinders on the rear locations and wider front shoes in later applications.

Mechanical brakes for model As made from mid to late 1928 on were designed to get the braking action more equal but there is a difference in the actuator shaft arm lengths between front and rear brakes that appears to favor the rear brakes as far as force application during the braking process. When you look at the model T it becomes apparent the model A was Ford's first chassis to have four wheel brakes. The early ones had an equalizer design so they differ from the later changes. Ford was new to all wheel braking systems at the time and the tires were still large diameter with narrow track so they just wanted the car to stop better than the model T.

I would adjust them by the Ford instructions if there are no modifications to them. The shoes need a good contact pattern. Part of that is by adjustment but arcing the shoes to fit the drums is the best way to get it right on the money. A lot depends in whether it has cast or stamped steel drums and the type of shoe lining material that is used.
 
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First, the brakes must be in good shape. The instructions say to adjust the brakes so that the rears do most of the work. I am not sure that is the best idea. I have been experimenting with biasing the braking to the front by backing off the rears a little and tightening up the fronts a little. The braking is definitely better by doing this. One cavaet: I have replaced the front actuating arms with rear ones. The rear ones are longer than the stock front ones.

When adjusting the brakes for the first time after a brake job, the real test is a panic stop at 20 mph. The car should stop within 25 feet and not pull to one side or the other. If the car pulls, tighten up the front brake on the side opposite to the pull. Once the brakes are well adjusted, it only takes an equal tightening on all wheels when it comes time to re adjust them. I should add that once the rods are the proper length they should not be adjusted. The proper length gives the right angle to the levers front and rear.

Update: My biasing my brakes to the front I was able to decrease my panic stop at 20 mph from 21 feet to 17 feet. The rears still skid but the fronts don't. In normal driving the brakes are a lot better.
 
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My car was pulling to the right under a hard stop prior to the adjustment so I had to fine tune the front left a little. Aside from that they were about the same so it was just a click more. Tonight after work I will set her on the ground and go for a test drive to see if she stops straight....if not a little more fine tuning.
 
A brake pull can occur from the rear brakes as well. Basically if it pulls the car to one side or another it’s the rear brakes, if it pulls the steering wheel it’s front brakes.

I skid to equalize the rears, then tighten fronts to a nose dip but no skid. I use modern radial tires on ‘35 ford wheels, traction is critical to stopping, skidding is loss of control of the vehicle..
 
I remember how even though the breaks on my 30 Tudor did not seem to need adjusting when I saw the knotched stick method I just had to try it. Car stopped fine after that. Sometimes just doing some old school stuff is neat.
A neighbor (in his 30's) came over to borrow an allen wrench to tighten the handlebars on his bike. I noticed that the knurling in the clamp were shot so a piece of duct tape was wrapped around the bar. Then when he had tighten the screws with the allen wrench I took a box wrench and gave them some extra torque. He smiled and said "Old guy trick". I smiled and said, pass it on... Chap
 
P Moore, The floater kits will equalize the wear. That is because both shoes are helped by the friction in braking.

To cure the pull to one side, do slight adjustments and then test drive. Repeat until you are satisfied. I just finished doing this and it took about 5 adjustments. Once you have the brakes adjusted to your liking, when it comes time to re adjust them, adjust each brake an equal amount. Then do a test drive. For those of you with stock brakes this means one or two clicks on each brake. For those of you with floaters it means 1/8 turn.
 
It used to be set the rear brakes to do most of the stopping but that was on mostly dirt roads when these cars were new.I set mine to a slight rear preference as I found out a panic stop with the front wheels locked is not a pleasant ride.
 
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