NHF150FF
New member
- First Name
- Joe
- Joined
- Sep 22, 2025
- Threads
- 1
- Messages
- 1
- Reaction score
- 3
- Location
- New Hampshire
- Vehicles
- 2021 F150 XLT 4x4 5.0L SCREW
- Thread starter
- #1
Thought I'd post my recent experience with a new-to-me F150. I purchased this truck less than a month ago with ~40K on it 'as-is' from a dealer with the balance of the power train warranty. I declined to purchase additional warranties for various reasons. I noticed it had add-a-leafs on the back springs but figured I'd see how it rode and take them off If I didn't like them. After driving over a steep driveway apron at an angle one of the leaf springs pops out of the rear eye... wasn't expecting that. Turns out both leaf spring rear eyes were cracked on the top between the eye and the bed of the truck. You couldn't see it unless you used a mirror (or you phone in selfie mode). After evaluating costs/time associated with stealership replacement vs. doing this myself, I elected to do the work myself (stealership wanted 5K and have the truck for 2-3 weeks). Maybe someone else can benefit from my experience:
Discovery:
Both Broken Springs:
Replacement Springs:
I elected to use aftermarket springs. This allowed me to revert back to a stock spring spacer instead of the cheapo 3" block that I found on the truck as they sit a bit taller. https://www.generalspringkc.com/202...y-leaf-spring-4-3-1-leaves-2400-lbs-capacity/
These springs are rated for more than my truck is rated (I don't have the max tow) and will reduce the payload by ~50lbs due to being heaver than stock. I do not plan on overloading the truck but I like that they don't have the composite spring.
U-Bolts:
I ordered a pile of u-bolts as I did not know what length would work best, and I did not know if the new springs would be square or semi-round like the stock ones. Turns out square 3" x 10" fit nicely. These came from rough country, P/N 7671.
Other bits:
If you don't want to drop your fuel tank and exhaust to access the front leaf bolts, cut them off and replace them backwards. I was able to find the bolts at Quirk Auto. Here's a picture of the ford stock parts and cutting the bolt:
I trimmed the replacement bolt on the fuel tank side a bit, just to keep as much space as possible between the bolt and the tank (I put it back reversed in case I ever have to do this again):
Observations:
I thought the ride would be a lot stiffer - it is slightly, but not enough that any of my passengers have noticed. The truck sits exactly the same as before (1.5" levelers in front, stock 4x4 spacer in back with new springs). Total swap time was about 4 hours taking my time on a gravel driveway. I suspect that the add-a-leafs caused some odd stress on the eye and resulted in a fatigue crack. The crack surfaces were pretty corroded, which suggests it had been there for a while. Check your springs!
Discovery:
Both Broken Springs:
Replacement Springs:
I elected to use aftermarket springs. This allowed me to revert back to a stock spring spacer instead of the cheapo 3" block that I found on the truck as they sit a bit taller. https://www.generalspringkc.com/202...y-leaf-spring-4-3-1-leaves-2400-lbs-capacity/
These springs are rated for more than my truck is rated (I don't have the max tow) and will reduce the payload by ~50lbs due to being heaver than stock. I do not plan on overloading the truck but I like that they don't have the composite spring.
U-Bolts:
I ordered a pile of u-bolts as I did not know what length would work best, and I did not know if the new springs would be square or semi-round like the stock ones. Turns out square 3" x 10" fit nicely. These came from rough country, P/N 7671.
Other bits:
If you don't want to drop your fuel tank and exhaust to access the front leaf bolts, cut them off and replace them backwards. I was able to find the bolts at Quirk Auto. Here's a picture of the ford stock parts and cutting the bolt:
I trimmed the replacement bolt on the fuel tank side a bit, just to keep as much space as possible between the bolt and the tank (I put it back reversed in case I ever have to do this again):
Observations:
I thought the ride would be a lot stiffer - it is slightly, but not enough that any of my passengers have noticed. The truck sits exactly the same as before (1.5" levelers in front, stock 4x4 spacer in back with new springs). Total swap time was about 4 hours taking my time on a gravel driveway. I suspect that the add-a-leafs caused some odd stress on the eye and resulted in a fatigue crack. The crack surfaces were pretty corroded, which suggests it had been there for a while. Check your springs!
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