Stock vs aftermarket u-bolts

[Patrick]

Is there any benefit to buying $160 u-bolts from Ford? I notice that they have a flat surface on the u portion of the bolt. I assume this doesn't concentrate so much force on a small area. Has anybody had a problem with regular round bolts? If not, why did ford do the flattened design?

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[martin]

easier for the robot to handle?

 

[Curious Hound]

Based on my experience with manufacturing robots, I doubt that it has anything to do with the robot. Fun thought, though.

After picking up a used 8.8 axle for my truck, I went to the junk yard and pulled some u-bolts there that were in excellent condition. Just a few dollars and I will have OEM u-bolts when I put the axle in.

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[holyford86]

I had some made when I replaced the springs, local spring shop made them, recommended going to 9/16 for my application and drilling holes larger, the flattened u bolts seem weak to me and load distribution would be a non issue on an axletube anyway

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[Patrick]

Hmm... yes, I suppose I've never heard of a damaged axle tube from u-bolts. As far as reusing them, I finally found a decent explanation of why it is a bad thing. It has to do with the rolled threads deforming when the bolt is initially tightened. Supposedly, you need more torque with each subsequent reuse to get the same clamping force.

http://www.eng-tips.com/viewthread.cfm?qid=256363

The only other reason for flattened u-bolts i can think of is to make it easier to install them straight up and down. But I think ill just buy the 40 dollar bolts for now. Maybe if I'm paranoid about it, then I can always buy the expensive ford ones down the road. Thanks for the input so far.

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[Z7What]

The only reason i would consider the OEM U-Bolts to be better is that they are course thread. Most of the aftermarket U-Bolts i have seen, have been fine thread and strip very easily. Although there are aftermarket U-Bolts that are course thread so which ever route you go make sure there course thread if you want my 2 pennies.

Wayne

 

[Curious Hound]

Patrick,

Thanks for the info. That is all interesting.

When I replace my axle, I will be installing a lift kit. If the kit comes with new U-bolts, I will use them. Otherwise, I will probably use my junk yard bolts and keep an eye on things regarding loosening or movement between axle and springs, etc.

I have worked in Industrial maintenance for most of my career and have heard many variations of "don't re-use fasteners". My personal philosophy is " it depends". - on the type of fastener, it's function, it's condition, etc. There is no good "one size fits all" answer, especially for those on a tight budget. And at work, management gets to weigh in on the decision, too.

 

[Blown]

I think locking them down to the proper torque is more important than stock vs aftermarket. Then they will need to be retightened at least once after driven for a bit. I always do so and they do take more torque after a decent length test drive.

I have heard of rigs spitting out lift blocks when the u-bolts where not re-torqued.

 

[85_Ranger4x4]

I had some made when I replaced the springs, local spring shop made them, recommended going to 9/16 for my application and drilling holes larger, the flattened u bolts seem weak to me and load distribution would be a non issue on an axletube anyway

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I learned you don't simply just drill out the holes bigger for bigger bolts. You have to hog out the outside with a die grinder. The only way for a bigger U bolt to fit on the center measurements as a smaller U bolt is for the bend to be smaller... not very feasible for going around an axle.

I thought I had the cats meow when I found a set of F-150 backing plates at the JY just sitting on top the springs. With my bigger than stock bolts nothing fit worth a darn and I ended up hogging out the holes to get it to work.

 

[Mac]

The only reason i would consider the OEM U-Bolts to be better is that they are course thread. Most of the aftermarket U-Bolts i have seen, have been fine thread and strip very easily. Although there are aftermarket U-Bolts that are course thread so which ever route you go make sure there course thread if you want my 2 pennies.

Wayne

It's not because of the fine threads but cheaper material in lot of the aftermarket. Fine threads are rated at a higher torque load.
Dave

 

[holyford86]

Reason the f150 spring plates didnt work is the axletubes are bigger, I had some bolts custom made

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[85_Ranger4x4]

Reason the f150 spring plates didnt work is the axletubes are bigger, I had some bolts custom made

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Both were 31 spline 8.8.

Drilling out holes moves what should be the inside of the u-bolt farther inside.

It doesn't line up quite right but this is what I am trying to say:

The holes have to line up so the ID of the bolt lines up with both hole sizes.
o o
O O

vs

o o
O O

Just drilling holes on the same center and the hole grows into where the axle tube is.

 

[holyford86]

My bad, didnt spend enough time reading that the first time.

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[saskbill]

I had some made when I replaced the springs, local spring shop made them, recommended going to 9/16 for my application and drilling holes larger, the flattened u bolts seem weak to me and load distribution would be a non issue on an axletube anyway

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+1 for getting them bent up locally^

Our local truck/trailer service place custom bends U-bolts (they have a stock of straight U-bolt blanks of assorted sizes and lengths. You give them your measurements, they grab the right blanks and set up their U-bolt press and bango - custom U-bolts for a reasonable price!