WHY "Self-Energizing" Drum Brakes Work So Well....

[V8COOPMAN]

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..... And Lockheeds SUCK Hugely!


Old Denny Odoms (our favorite"tubman" here on the 'Barn) kinda started this last night with a couple of comments in reply to a question by "SoCalCoupe" The question and tubman's reply were as follows:



"SoCalCoupe" asked:

Why are the Lincoln brakes better? I'm guessing they're just bigger and have a wider range of pedal pressure before they lock up.


"tubman" was absolutely correct with his short answer:

"Mainly, because they are self-energizing, unlike the original Lockheed types.

This means that the action of braking itself increases the pressure on the shoes, rather than relying on just your leg."


Well, that's when I just had to come-up with a long-overdue explanation of exactly what "Self-Energizing" brakes means. When it finally dawns on you just what all the excitement is about, it's clear as night & day why the "Bendix" (Self-Energizing) brakes are all the stir. So with all that, tubman is correct, but let's dig just a little deeper. This is a little tutorial of sorts that I stirred-up a while back in an attempt to make it more clear just how "SELF-ENERGIZING" (also known as "Bendix-type") brakes work. BELOW is a perfect example of a Lockheed - Ford "non-self-energizing" brake assembly. Simple as it gets with two shoes, each shoe fixed to rotate on a pin at the bottom. The top half of each shoe produces some friction against the drum, depending on how hard you can push.




Most-assuredly, there is NO "Self-Energizing" going on here.


Then, Bendix came-up with a revolutionary design that once you get the shoes to touch the drum and ROTATE (as an assembly) in the direction of rotation of the drum. Picture BELOW is of an early Bendix brake backing plate. I chose it to easily illustrate the pieces involved in an early, simple, Bendix (or "self-energizing") drum brake.





They will bolt to the early Ford spindles and early rear end with no fuss. Without the shoes being directly tied to the backing plate, the whole shoe mechanism is able to rotate in the forward direction of the drum as the shoes begin to expand at top and succumb to friction with drum. In this typical "Bendix"-type configuration, I figure the MOST important part of the whole assembly is the ANCHOR PIN. It is the TINY-Looking piece at the very top to which the two springs are hooked. Actually, the pin looks more like this picture BELOW.



When properly centered and locked-down in the CORRECT location on the backing plate, the pin is immovable. It also determines how far inboard the brake shoes will retract, as each shoe has a corresponding rounded surface which should match the proper geometry when the shoes are centered in the DRUM. In other words, there SHOULD be some provision for adjusting this pin upward, or downward BEFORE tightening in place.

After you watch this short video below, you will see how that pin allows no CIRCUMFERENTIAL movement of the REAR shoe. The REAR shoe can only be jammed into the rear half of the drum by the FRONT shoe being rotated by the forward rotation of wheel. The REAR shoe cannot be rotated because that pin restricts the rotation of the REAR shoe. Rear shoe's friction surface just gets pushed harder and harder into the rear of drum's stopping surface. Click the link BELOW for short, 3-minute video - THE MOST-IMPORTANT PART. Easy-peazy!

https://youtu.be/n0OFhyxo4As


Coop

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[Ford Freak]

I installed Bendix style brakes on the front of my '37coupe.
BIG improvement. Now, I no longer need to stand on the pedal to stop!

[rockfla]

Thank you Professor Coopman, especially for the video too as I am more of a visual than spoken word learner!!! Good to see you putting in your dollars worth here on the barn my friend.......Still praying and thinking about you!!!!

[Lawrie]

It would be good if you could adapt then to work on mechanical brakes ,
Lawrie

[51woodie]

Coopman. I thought the picture of the Bendix brakes looked familiar, as it is a pic of the ones I installed on my ‘46 Coupe. I recognized the safety stand and the orange brake lubricant on the end of the adjuster. I’m glad you used it to aid in your explanation. I learned how these brakes function in high school auto shop, a lot of years ago.

[Jack E/NJ]

Sponsored Links (Register now to hide all advertisements)

And here I am still waiting for FlatHeadTed's floater kit for Lockheeds.

[19Fordy]

V8: Thanks for posting and explaining that excellent Bendix presentation so clearly.
Hope you are doing ok.

[drgoetz]

I looked at the picture of the "later" Lockheed-Ford brakes. Anchored at the bottom and the shoes can't move.
I use the 39-42 brakes that allow the bottom of the shoes to be adjusted out close to the drum... like the top.
Granted, the Bendix style brakes work really well, however, I have several complete sets of '39--'42 Lockheed's and they work OK for my purposes 'cause I really don't get out on the expressway.
If I had Bendix brakes I'd use them.

[A bones]

Thank you V8COOPMAN, for opening this up.
I was raised in a gas station, servicing brakes, while my buddies were doing their schoolwork.

Originally Posted by Lawrie

It would be good if you could adapt them to work on mechanical brakes ,
Lawrie

So... What is the deal with Ted's floaters?

[Jack E/NJ]

A while back, Ted said he was still testing floaters for Lockheed hydraulics.

[Juergen]

Originally Posted by Lawrie

It would be good if you could adapt then to work on mechanical brakes ,
Lawrie

the 37-38 Ford cable (mechanical) brakes were self energizing.

[mcgarrett]

Has anyone ever attempted to modify Lockheed brakes to operate like the Bendix units? It seems that an enterprising person could figure out a way to convert them, but would like to hear opinions from others more familiar with the differences.

[Fred A]

I've been using Bendix brakes since '63. A lucky time for available Zephyr brakes. As the supply thinned out in later years, replacements were developed, getting better all the time. I've been lucky to find Bendix made backing plates with the nice outer ring every time they were desired. The Ford/Zephyr drums look best with the rings. Seems that there were converted Lockheed backing plates available but the Dave Wilton/Boling/Bob Wilson offerings were a better choice. The Bendix made brakes still have all the snob appeal. Good Luck: Fred A

[34fordy]

Great thread V8COOPMAN ! Thanx. I wonder where and why the names Bendix and Lockheed were used.

[Zeke3]

Perhaps the names of the companies or persons that invented them?

[mhsprecher]

This is a great thread, especially because I have just finished redoing the Lockheeds on my 29 Ford. They stop well enough, but your brakes can never be too good.

Like A-bones, I worked in a gas station in high school and changed many brake shoes for self energizing brakes. Nice to know the principle behind them.

As an aside, a Corvette came in to the gas station where I worked to get new brake pads. It was the first set of discs that we service there and we were amazed at how easy it was to change the brake pads!

[V8COOPMAN]

Originally Posted by 34fordy

Great thread V8COOPMAN ! Thanx. I wonder where and why the names Bendix and Lockheed were used.

"Bendix" is an old trademark name that has been heavily involved with industry (especially automotive industry) for decades. BENDIX is into everything! "Lockheed - Wagner" is another huge corporation that you have seen involved with automotive suspension and brake parts/systems for eons, also.

Coop

.

[V8COOPMAN]

Originally Posted by mhsprecher

As an aside, a Corvette came in to the gas station where I worked to get new brake pads. It was the first set of discs that we service there and we were amazed at how easy it was to change the brake pads!

Now ain't THAT a kick! Pull your "gee-whiz" Corvette into the local Esso station one Saturday morning so that some greasy Goober-kid can practice replacing parts of a NEW brake system that he and his pals ain't never seen before.


Coop

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[HDowse]

Juergen is fight about the 37-38 cable brakes being self energizing. The wheel has different length shoes and four different springs that must be placed in the correct order to function as designed. There’s a relatively steep hill near my home and when going down I can lightly apply the brakes with some decent results. But when I put just a little more force on the pedal, the braking force is significantly more noticeable as the self energizing kicks in. Because the cables get sticky with old grease or even worse corrode, they have a less than stellar reputation. I replaced the cables on the 37 pickup a year or so ago and it stops better than my 40 sedan with Lockheed brakes. Given this discussion, it’s time for me to spring for the Bendix replacements, at least on the fronts.

[38 coupe]

The best brakes I have ever experienced were Lockheeds on a 40 Ford sedan. Softer linings probably, they were used off a hydraulic converted 38 Ford, 46 front cylinders, and 41 3/4 ton rear cylinders. That car stopped!
Good Lockheeds match Bendix units, you just have to know how to set them up.