rear drum size
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From: mohnton
rear drum size
i am look at rear drum kits for 96 f250 psd and I see two sizes. 12x3 and 12x2.5. is there a advantage or disadvantage to either, or is there a certain one I need for my truck?
Post Fiend
Joined: Mar 2011
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From: Backwoods of Snowflake AZ
RLA and Kris are not correct on this.
The 2.5" are for non-full floater axles (the ones that don't have the axle shaft sticking way out) and the 3" are for the full floaters (the ones that do have the axle shaft sticking way out).
3.5" is for duallys.
I know because I have been threw this 3-4 times while doing my own brake jobs and buddies brake jobs.
The F250 and F350 axle are the same I think only difference is either the blocks or the leaf springs can't remember for sure.
Another way to know for sure is measure the brake drum. I was personally able to do this with the wheels on my brother's 91 F250.
Trav
Posting Guru
Joined: Apr 2012
Posts: 1,693
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From: Menifee, CA
RLA and Kris are not correct on this.
The 2.5" are for non-full floater axles (the ones that don't have the axle shaft sticking way out) and the 3" are for the full floaters (the ones that do have the axle shaft sticking way out).
3.5" is for duallys.
I know because I have been threw this 3-4 times while doing my own brake jobs and buddies brake jobs.
The F250 and F350 axle are the same I think only difference is either the blocks or the leaf springs can't remember for sure.
Another way to know for sure is measure the brake drum. I was personally able to do this with the wheels on my brother's 91 F250.
Trav
The 2.5" are for non-full floater axles (the ones that don't have the axle shaft sticking way out) and the 3" are for the full floaters (the ones that do have the axle shaft sticking way out).
3.5" is for duallys.
I know because I have been threw this 3-4 times while doing my own brake jobs and buddies brake jobs.
The F250 and F350 axle are the same I think only difference is either the blocks or the leaf springs can't remember for sure.
Another way to know for sure is measure the brake drum. I was personally able to do this with the wheels on my brother's 91 F250.
Trav
Post Fiend
Joined: Mar 2011
Posts: 10,080
Likes: 5
From: Backwoods of Snowflake AZ
Yes usually on lower then 8800LB GVWR trucks but I have seen a truck or two that is higher then 8800LB gvwr that was with a semi floating axle granted I don't know if it was original as the truck was in a junkyard.
Trav
Trav
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Fleet Owner
Joined: Oct 2005
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From: Kentucky
Yep...missed the 3.0" vs 2.5" shoe width. My eyes saw one thing my brain typed another. Semi floaters used 2.5" width (F250 only). SRW F350s used 3" and DRW used 3.5" shoes.
Sorry...
Sorry...
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Fleet Owner
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From: Mi'kma'ki
summary;
F250 light duty (under 8600 lbs gross weight rating) these sport a semi floating rear axle. 2.5" wide shoe.none of these trucks housed the big blocks or diesels.
F250HD (the most common f250 of the era) sports the same full floating axle the srw f350 uses. 3" rear brake shoe.
F350 SRW 3" rear brake shoe.
F350 DRW 3.5" rear shoe.
F250 light duty (under 8600 lbs gross weight rating) these sport a semi floating rear axle. 2.5" wide shoe.none of these trucks housed the big blocks or diesels.
F250HD (the most common f250 of the era) sports the same full floating axle the srw f350 uses. 3" rear brake shoe.
F350 SRW 3" rear brake shoe.
F350 DRW 3.5" rear shoe.
7th Gear
Joined: May 2025
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summary;
F250 light duty (under 8600 lbs gross weight rating) these sport a semi floating rear axle. 2.5" wide shoe.none of these trucks housed the big blocks or diesels.
F250HD (the most common f250 of the era) sports the same full floating axle the srw f350 uses. 3" rear brake shoe.
F350 SRW 3" rear brake shoe.
F350 DRW 3.5" rear shoe.
F250 light duty (under 8600 lbs gross weight rating) these sport a semi floating rear axle. 2.5" wide shoe.none of these trucks housed the big blocks or diesels.
F250HD (the most common f250 of the era) sports the same full floating axle the srw f350 uses. 3" rear brake shoe.
F350 SRW 3" rear brake shoe.
F350 DRW 3.5" rear shoe.
Fleet Owner
Joined: Jul 2006
Posts: 20,400
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From: Mi'kma'ki
You're either mistaken or someone replaced your rear axle with a lighter duty one and you should swap a full floating rear back in it (they're cheap enough and always use new U-bolts).....along with the wider 3" brake shoes.
If you don't haul heavy and or wont swap the correct rear back in, then the semi floater that someone swapped in, uses the 2.5" wide brake shoes. Don't buy the 3" shoes the truck originally came with, because they wont fit now. That rear doesn't belong in your truck. Someone needlessly ruined it and since it's a very affordable (and easy/fast) fix, it should be fixed.
My F250 has a F350 DRW rear in it now. I can't buy the 3" shoes my truck originally came with either. You have to buy shoes for the rear that's in there now. Take your drum off and measure the shoe. You'll see.
7th Gear
Joined: May 2025
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That should never be the case. Are you sure you know what a semi and full floater look like?
You're either mistaken or someone replaced your rear axle with a lighter duty one and you should swap a full floating rear back in it (they're cheap enough and always use new U-bolts).....along with the wider 3" brake shoes.
If you don't haul heavy and or wont swap the correct rear back in, then the semi floater that someone swapped in, uses the 2.5" wide brake shoes. Don't buy the 3" shoes the truck originally came with, because they wont fit now. That rear doesn't belong in your truck. Someone needlessly ruined it and since it's a very affordable (and easy/fast) fix, it should be fixed.
My F250 has a F350 DRW rear in it now. I can't buy the 3" shoes my truck originally came with either. You have to buy shoes for the rear that's in there now. Take your drum off and measure the shoe. You'll see.
You're either mistaken or someone replaced your rear axle with a lighter duty one and you should swap a full floating rear back in it (they're cheap enough and always use new U-bolts).....along with the wider 3" brake shoes.
If you don't haul heavy and or wont swap the correct rear back in, then the semi floater that someone swapped in, uses the 2.5" wide brake shoes. Don't buy the 3" shoes the truck originally came with, because they wont fit now. That rear doesn't belong in your truck. Someone needlessly ruined it and since it's a very affordable (and easy/fast) fix, it should be fixed.
My F250 has a F350 DRW rear in it now. I can't buy the 3" shoes my truck originally came with either. You have to buy shoes for the rear that's in there now. Take your drum off and measure the shoe. You'll see.
7th Gear
Joined: May 2025
Posts: 7
Likes: 0
