The Ford Barn

Stingray70 · 09-02-2022, 07:37 AM

Ok probably overthinking this but here goes:
When setting the front brakes, the book says the lever should be set to 15 degrees forward. 15 degrees from what? Kingpin? Perpendicular to brake rod? Vertical? I can't find a reference but vertical would be almost impossible to achieve.

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Big hammer · 09-02-2022, 07:54 AM

Vertical before they begin to move, pills in the wedges to take up slack

jb-ob · 09-02-2022, 08:08 AM

Stingray....

IF your backing plates, internal brake parts & cross shafts are correctly restored, the brake lever will sit at 15 degrees forward. You may need a single brake pill but any more 'tells' you, you missed something during the front brake restoration.

Stingray70 · 09-02-2022, 08:32 AM

What I mean is to what line do I measure the 15 degrees? Vertical from the floor? That would not be accurate because the car could be sitting an infinite range of angles.

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katy · 09-02-2022, 09:43 AM

Quote:

Originally Posted by Stingray70

What I mean is to what line do I measure the 15 degrees? Vertical from the floor? That would not be accurate because the car could be sitting an infinite range of angles.

Sent from my SM-G950U using Tapatalk

90° from the floor.

Phil Brown · 09-02-2022, 09:46 AM

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15 deg. From vertical, plumb, or straight up and down, how ever you prefer to say it

nkaminar · 09-02-2022, 10:17 AM

It does not have to be exactly 15 degrees. The purpose is to have the arm near vertical when the pedal is pressed hard so that the maximum amount of the rod force is used to activate the brake.

If you want to be exact, it should be 15 degrees from a perpendicular from the brake rod. So you could cut a piece of cardboard to 75 degrees (15 degrees less than 90) and use that to set the arm relative to the brake rod.

Bob Johnson · 09-02-2022, 11:13 AM

What you want is for the lever to be vertical with respect to the axle when the brakes are being applied. That will give you maximum pressure on the brake shoes to drum. Have one person step on the brake pedal while another person observes the lever. If it is vertical when the brakes are applied you are good to go.

How important is it to have the 15 degrees? What if you are off ? The force on the lever is dependent on the angle. At 0 degrees you get 100 percent of the applied force. The force is proportional to the COS of the angle. Thus at an angle (when the brake are applied) of 5 degrees you get 99.6 percent of the force. Or you are loosing 0.4 percent. If you are off by 20 degrees then you get 94 percent. I doubt that any brake system will be off by that much.

Bob johnson

Stingray70 · 09-02-2022, 06:15 PM

Perfect. That was just what I was looking for. Thanks guys.

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Bob Bidonde · 09-04-2022, 09:11 AM

These slides should help you understand the 15-degree angle:

norcalal · 09-04-2022, 08:21 PM

I usually put enough pills under the actuating rod to take up more slack, making the arm lean forward more than 15 degrees. Is this reducing effective braking?

09-02-2022, 07:37 AM	#1
Stingray70 Senior Member Join Date: Jan 2021 Location: Western NC Posts: 213	Front brake lever angle Ok probably overthinking this but here goes: When setting the front brakes, the book says the lever should be set to 15 degrees forward. 15 degrees from what? Kingpin? Perpendicular to brake rod? Vertical? I can't find a reference but vertical would be almost impossible to achieve. Sent from my SM-G950U using Tapatalk __________________ 1930 Standard Coupe

09-02-2022, 07:54 AM	#2
Big hammer Senior Member Join Date: Jun 2014 Location: Land of Lincoln Posts: 3,131	Re: Front brake lever angle Vertical before they begin to move, pills in the wedges to take up slack __________________ Don't force it with a little hammer tap, tap, tap get a bigger hammer tap done

09-02-2022, 08:08 AM	#3
jb-ob Senior Member Join Date: Jun 2010 Posts: 640	Re: Front brake lever angle Stingray.... IF your backing plates, internal brake parts & cross shafts are correctly restored, the brake lever will sit at 15 degrees forward. You may need a single brake pill but any more 'tells' you, you missed something during the front brake restoration.

09-02-2022, 08:32 AM	#4
Stingray70 Senior Member Join Date: Jan 2021 Location: Western NC Posts: 213	Re: Front brake lever angle What I mean is to what line do I measure the 15 degrees? Vertical from the floor? That would not be accurate because the car could be sitting an infinite range of angles. Sent from my SM-G950U using Tapatalk __________________ 1930 Standard Coupe

09-02-2022, 09:46 AM	#6
Phil Brown Senior Member Join Date: May 2010 Location: Santee Calif. Posts: 509	Re: Front brake lever angle Sponsored Links (Register now to hide all advertisements) 15 deg. From vertical, plumb, or straight up and down, how ever you prefer to say it

09-02-2022, 10:17 AM	#7
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,897	Re: Front brake lever angle It does not have to be exactly 15 degrees. The purpose is to have the arm near vertical when the pedal is pressed hard so that the maximum amount of the rod force is used to activate the brake. If you want to be exact, it should be 15 degrees from a perpendicular from the brake rod. So you could cut a piece of cardboard to 75 degrees (15 degrees less than 90) and use that to set the arm relative to the brake rod. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

09-02-2022, 11:13 AM	#8
Bob Johnson Senior Member Join Date: May 2010 Location: California Posts: 979	Re: Front brake lever angle What you want is for the lever to be vertical with respect to the axle when the brakes are being applied. That will give you maximum pressure on the brake shoes to drum. Have one person step on the brake pedal while another person observes the lever. If it is vertical when the brakes are applied you are good to go. How important is it to have the 15 degrees? What if you are off ? The force on the lever is dependent on the angle. At 0 degrees you get 100 percent of the applied force. The force is proportional to the COS of the angle. Thus at an angle (when the brake are applied) of 5 degrees you get 99.6 percent of the force. Or you are loosing 0.4 percent. If you are off by 20 degrees then you get 94 percent. I doubt that any brake system will be off by that much. Bob johnson

09-02-2022, 06:15 PM	#9
Stingray70 Senior Member Join Date: Jan 2021 Location: Western NC Posts: 213	Re: Front brake lever angle Perfect. That was just what I was looking for. Thanks guys. Sent from my SM-G950U using Tapatalk __________________ 1930 Standard Coupe

09-04-2022, 08:21 PM	#11
norcalal Member Join Date: May 2010 Posts: 79	Re: Front brake lever angle I usually put enough pills under the actuating rod to take up more slack, making the arm lean forward more than 15 degrees. Is this reducing effective braking?