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Old 05-25-2015, 04:45 AM   #1
bikemaniac
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Smile Drum brake ovality?

Hi,
When applying my stock drum brakes, the decelleration is jerky in the sense that for each wheel revolution the brakes brake harder at approx 50% of a revolution and softer at the remaining 50%. Is this normal or can/should it be solved?

Next, concerning brake performance: When riding in town at lets say 40 mph approaching an intersection with lights .... and the lights suddently turn red, I have a very long brake distance compared to a modern car, I almost every time end up in the intersection and have to back up a little. I feel I really press the brakes hard .... but maybe I should REALLY press with all I have got? I know the car weighs more than 2000 pounds, but still .... how would you describe the brake performance?

Lucas
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Old 05-25-2015, 07:30 AM   #2
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Default Re: Drum brake ovality?

First paragraph - your brake drums are WARPED.
Second paragraph - your brakes are LOUZY and need to be replaced before someone gets hurt or worse killed. They are not only warped but very thin from years of turning and returning. Thin drums do not dissipate the heat. The hotter they get the more they expand - the more they expand the harder you have to stomp.

I was driving my '28 Pickup one day two years ago and came upon the only traffic light in Van, TX. My drums were warped and very thin like yours and the harder I stomped the faster the truck went. She finally came to a stop directly under the red light. I was lucky no cars were coming the other direction. I backed up and waited for my green light, then took her home - carefully - then parked her in the garage until I could completely rebuild the brake system. She can now slide all four tires on the pavement.

Luv dat wurd "ovality". ken
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Old 05-25-2015, 07:35 AM   #3
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Default Re: Drum brake ovality?

"how would you describe the brake performance?"
My description is "very typical" for Model A's that need the brakes rebuilt.
That performance is what gave the Model A it's reputation of poor/bad brakes.
To fix the problem will require rebuilding the brake system. As others will comment, a properly restored brake system will stop the Model A properly and safely. If you do not know how to do this, please get some help. Books, videos, etc., are available to help you get the job done yourself. If you choose not to attempt it find someone that knows how to do it.
I will add that there are no short cuts or band aids. A total rebuild is the best way to correct the problem.
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Old 05-25-2015, 07:44 AM   #4
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Default Re: Drum brake ovality?

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Originally Posted by bikemaniac View Post
I know the car weighs more than 2000 pounds, but still .... how would you describe the brake performance?

Lucas
You should be able to slide all 4 wheels/tires repeatedly when correct. As others have stated, please restore them correctly before driving the car any more.
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Old 05-25-2015, 08:05 AM   #5
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Default Re: Drum brake ovality?

In the meantime, learn to keep an eye out so that you are ready to hit something cheap.
Good Luck!
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Old 05-25-2015, 06:11 PM   #6
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Default Re: Drum brake ovality?

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agreed warped drums and brake system needs rebuilt. how far from the floor is the pedal when your stopping hard?
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Old 05-25-2015, 06:58 PM   #7
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Default Re: Drum brake ovality?

Its definitely no fun driving a car with known poor brakes or steering. Good advice from MAG & BRENT. Les Andrews Mechanics Handbook (Vol I) and other resources are great for identifying and addressing mechanical issues. I just replaced worn out drums with new cast type from Snyders. Also installed new linings, cams/camshafts...etc for a complete restoration. Brakes now work as well as a modern car.
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Old 05-26-2015, 02:34 AM   #8
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Default Re: Drum brake ovality?

Brake drums sound worn and warped.
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Old 06-09-2015, 05:14 PM   #9
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Default Re: Drum brake ovality?

When I bought the car last year, the previous owner told me that the brakes had been serviced 42 years ago just before the car was put away in a storage container for 42 years.

Today I looked at one of the brakes and everything looks new to me ... what do you think?

http://s1353.photobucket.com/user/lu...d%20A%20brakes

The cast iron drums are not worn at all.

Lucas
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Old 06-09-2015, 05:34 PM   #10
Chuck Sea/Tac
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Default Re: Drum brake ovality?

It sounds like you need to go thru and adjust as needed. This includes rods, shafts the correct position of the acuating levers ect. New drums and shoes do not make a good system. It all has to be no wear and in sync.
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Old 06-09-2015, 05:53 PM   #11
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Default Re: Drum brake ovality?

I would also pull the shoes and check the roller tracks for wear.

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Old 06-09-2015, 05:58 PM   #12
Kurt in NJ
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Default Re: Drum brake ovality?

I can't see the tops of the shoes because they are cut off in the picture, but it looks like the upper 1/3 of the shoe isn't touching the drum by looking at the wear pattern shown
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Old 06-09-2015, 06:32 PM   #13
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Default Re: Drum brake ovality?

The drum is steel not cast iron, and the stud is welded in. The shoes are not centered. That is the way I did my brakes the 1st. time and it stopped the way you described.
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Old 06-10-2015, 12:17 AM   #14
bikemaniac
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Default Re: Drum brake ovality?

Quote:
Originally Posted by Rod-MI View Post
The drum is steel not cast iron, and the stud is welded in. The shoes are not centered. That is the way I did my brakes the 1st. time and it stopped the way you described.
Well, the drum has this coarse surface which is normal when being sand cast ... you see the imprints from all the sand particles. What welded in stud are you talking about and how can you tell the shoes are not centered ... to me it looks pretty much centered. Thanks.

Lucas
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Old 06-10-2015, 07:33 AM   #15
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Default Re: Drum brake ovality?

In the first picture there is a wheel stud with weld at the edge, the tops of the shoes the lining color is brownish, the lower section dark grey showing the weave of the lining is the only part contacting the drum ---this shows the shoes are not centered
To see if stamped or cast you need a picture showing the edge of the drum from the other side, ---42 years ago the cast drums had big open holes covered by the wheel(most times called rocky mountain drums), and not much in "repros" could be bought
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Old 06-10-2015, 09:09 AM   #16
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Default Re: Drum brake ovality?

Lucas, it sounds like you are reluctant to do whats necessary to get good brakes. Of course the seller would tell you the brakes are "rebuilt". Most replies here are telling you the truth: those are steel drums, warped, with improperly arced shoes that do not fit. Ford did not recommend turning those drums, they recommended replacing them when worn. Even when new, steel drums give poor results. I would guess the tracks are worn too which means the shoes are not centered. You do not want to be in an accident in a Model A. Cutting corners on brakes can get you or someone else killed. The brakes need a total rebuild using new cast iron drums, soft molded linings that are arced and centered, with all worn levers, bushings, rollers, tracks, clevises and pins replaced. A Model A can and should stop almost as well as a modern car.
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Old 06-12-2015, 05:44 PM   #17
bikemaniac
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Default Re: Drum brake ovality?

Should you be able to fully block the brakes at 30 mph?
My brake lever is pointing forward with approx 15 deg as mentioned in the Les Andrews manual. Is the end position at 12 o clock (fully depressed brakes) or should the lever be able to turn further towards the rear of the vehicle?
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Old 06-12-2015, 06:40 PM   #18
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Default Re: Drum brake ovality?

Quote:
Originally Posted by bikemaniac View Post
Should you be able to fully block the brakes at 30 mph?
My brake lever is pointing forward with approx 15 deg as mentioned in the Les Andrews manual. Is the end position at 12 o clock (fully depressed brakes) or should the lever be able to turn further towards the rear of the vehicle?
I would say the brakes should lock by the time the front lever is vertical. If they don't, then you may need to adjust them tighter. They won't need the "pill" since you said they are 15* forward.
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