Drum Size Question

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May 13, 2019 | 09:01 PM

DH166

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4wd High

Joined: Jan 2019

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Drum Size Question

I have a 1981 F100 Custom SWB with manual brakes. Without pulling the wheel off and measuring, is there a way to know whether I have 10" or 11" rear drums?

May 14, 2019 | 07:29 AM

FuzzFace2

FTE Legend

Joined: Nov 2015

Posts: 30,941

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From: Angier, NC

Not really but the wheel bolt pattern is also different between them.
The nonpower would be the large pattern at 5 x 5.5 IIRC.
When I get home and can remember I will measure my old drums to see what they were as I don't remember now.
The only thing I can remember being the same between the 2 sizes are the wheel cylinders, can't remember if the spring kits are the same?

Everything up front from brakes to kingpins is different between power & nonpower / small & large bolt pattern.
Been there, done that on my 81 flare side.
Dave - - - -

May 15, 2019 | 03:17 AM

NumberDummy

Ford Parts Specialist

Joined: Nov 2006

Posts: 88,826

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From: Simi Valley, CA

Quote:

Originally Posted by DH166

I have a 1981 F100 Custom SWB with manual brakes. Without pulling the wheel off and measuring, is there a way to know whether I have 10" or 11" rear drums?

1980/83 F100 with manual front disc brakes, 5 lug wheels on a 5.50" bolt circle = 11" x 2 1/4" rear drum brakes.

1980/82 F100 with power front disc brakes, 5 lug wheels on a 4.50" bolt circle = 10" x 2 1/2" rear drum brakes.

May 15, 2019 | 04:29 AM

FuzzFace2

FTE Legend

Joined: Nov 2015

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From: Angier, NC

Thanks Bill
I could not drag myself out to the garage, out the door at 2am and back in at 4pm is a long day.
Dave - - - -

May 15, 2019 | 04:43 AM

NumberDummy

Ford Parts Specialist

Joined: Nov 2006

Posts: 88,826

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From: Simi Valley, CA

Quote:

Originally Posted by FuzzFace2

Thanks Bill
I could not drag myself out to the garage, out the door at 2am and back in at 4pm is a long day.
Dave - - - -

One a these days you'll retire, but if you think you'll have more time to do the things you want...you won't.

I've been up since 8:30 AM yesterday...and it's now 2:45 AM today.

May 15, 2019 | 04:55 AM

FuzzFace2

FTE Legend

Joined: Nov 2015

Posts: 30,941

Likes: 4,126

From: Angier, NC

Quote:

Originally Posted by NumberDummy

One a these days you'll retire, but if you think you'll have more time to do the things you want...you won't.

I've been up since 8:30 AM yesterday...and it's now 2:45 AM today.

I hope I can retire in 5 to 7 years.
Up at 2am today for a AM delivery, got to site at 430 and no one here and still waiting now 6am.
Going to mess up my next delivery by 12pm and I have to drive 120 miles each way to get load & drop it.

830 yesterday till now! Can't sleep?
I get on the forum and I start to fall asleep but need stay up tI'll I get my loads for the day.
Dave - - - -