Hey all! Just looking for opinions... I've just about done with the b-code mod (https://www.ford-trucks.com/forums/1...p-by-step.html), and putting stuff back together. I noticed 2 things and wonder if maybe i've got defective U-Bolts...


I'm tightening them using a 10 inch ratchet till they are pretty snug (I almost can't tighten anymore), then switched to my 250ft lb torque wrench that is 2ft long. As I approach 150-160 ft lbs, they start to bend. It happened on the other side as well, only very slightly bent at the very end (almost can't tell without a straight edge.) Also, before even putting them on I noticed one ubolt is about 3/4 of an inch longer on one side. I had to cut it to get it to work with my deep socket.


Do I have defective UBolts? Am I tightening something incorrectly?


bent ubolt

 

Wow, I've never seen those bend before. I too have used a 3 foot cheater until I couldn't turn any more. They're definitely stretching. Why is the bent one so much shorter than the others?

 

Are they OEM Ford bolts? If not, who makes them etc?

That spacer block too...what's that from...your truck is obviously lifted, and the B code mod typically doesn't use such a large block.

 

What dia. are the u-bolts? 160 ft pnds is too much and could cause the bending. Spec for grade 8 in 9/16" dia is 115 for coarse thread and 129 for fine thread.

I could be wrong but why are you going so high?

There is a sequence to tightening, just google it

 

I think you have gone too tight. I believe the rears should only be 145.

Since I got my bolts here, this is the torque specs I had. http://www.autoandtrucksprings.com/p...lt_Torque.html

 

To answer questions...
It's a 3.5" block. Yes, the truck was lifted and it's not a 100% standard bcode mod. All is pretty much normal except for the 3.5" block. The bolts are 5/8" grade 8s at 14.5" long from ATS (via Cary at ctperformance) and the torque spec that came with the ubolts says 177 lbs. but to "follow ford spec if it's different" which is 185lbs. As I already said, I ended up cutting one because my deep socket was slipping off the top of it, that's why it's shorter. In all, I don't see how anyone doing the b code mod would use 14.5" u bolts. I mean, i'm 1.5 inches higher cause of block and my super large deep socket barely sits on top of the bolt?!?!


Update / BAD TORQUE info?
I took it all apart and it appears my top plate was bending on one side under the pressure of the bolts. Top plate is now trash. Check it out...






Odd that only one side did this. However, on the other side of vehicle, all bolts are evenly bent ever-so-slightly maybe 3 - 5 degrees to the outside. Is that at all normal or no?






I see no way that the top plate is made for 185lbs of torque. I get that it's Ford spec and the bolts should handle it. But, the stock plate on the excursion won't take it. There were indents underneath it from the springs and the washers had dug in at least 1/8" deep into metal!!! No way it can handle anymore than maybe 150lbs tops. Either I REALLY missed something here or these torque specs for the b-code mod are just plain wrong.




Kinda frustrated and would like to hear from other's who did the b code mod. Either everyone is missing this and effing up their bolts and just noticing or they aren't actually torquing to 185lbs. Did you actually torque to 185lbs? Are any of your bolts slightly tweaked to the outside?

 

They shouldn't bend, something isn't right. For a 5/8" grade 8 you are In range of spec but as you mentioned the spring plates may not be able to handle that much torque. I know my ATS are 9/16" and no issues with the u-bolts.

You bought the u-bolts from CTPerformance, I would start there.

 

Talked to a lot of people including CT, Ford and ATS. ATS really set me straight with "the rest of the story"...


Basically, don't do this job without buying new top plates! BTW: They sell them for less than Ford (Ford is $45). They've had this issue (imagine that I'm NOT the first!) and said it's common for the original top plates to be fatigued etc. Their top plate is actually higher quality than Ford OEM. FYI - I'd recommend anyone doing this inspect their top plate first and probably just replace it as mine showed no previous signs of wear that I could see, yet still bent.


Saves yourself a lot of money in the long run and... as others have said: No! Bending like that is not at all normal and both sides should be re-done. Hope this helps someone before they do the B Code mod!

 

This is the first time in years of being on here that I have read about one bending like that. I just don't see that plate being fatigued enough to just bend like that the next time you torque it. Have you had your torque wrench calibrated or compared to a known good wrench?

 

Yes. I had the torque wrench checked when I ran into this issue. Wrench is good. And remember this starts happening around 150lbs. So, let's say my wrench was so off that I was at 150lbs and it was really over-torque'd at that setting it would have to be off by more than 35lbs! which is a huge amount - one would notice!

 

If you take the picture from another angle, I'm going to guess the threads on the side of the one u-bolt that is higher start higher too.

What happened is incorrect sequencing, you went too tight on that high end before tightening up the other side of the same bolt so you started to rotate the bolt around (IE change where the bend is in the u-bolt).

There may be more contributing factors, but that's why you ended up with lower threads on one side and much higher on the other for that one bolt.


EDIT: If that's the side you cut, it's going to be the opposite.

 

Correct! But, I noticed this was the case BEFORE I put them on the truck. Bolt defect?



I don't see how... I did a cross pattern doing only 1 bolt turn each and stopping every 20ft lbs to even all of them out. If it was from un-even tightening, how do you explain the failed top-plate?


Will know for sure this week. I have new top plates and I'm just waiting for new u-bolts. Round 2!

 

If it was that way before you it on it means whoever was making the bolts didn't center it correctly prior to bending. Not necessarily a structural defect in the strength of the bolt but yes, a defect.

Uneven tightening could put a lot of stress at one corner, say if both opposing bolt positions are tightened. While the bolt will tend to start to pulling around it will still put a lot of force on the top plate. In this case, the bend would most likely to be adjacent to the position where the least tightening was done (not that hole, but one next to it).

In your case the two may just be coincidental though.

 

Sorry, forgot to post an update to this.


There was nothing wrong with how I was tightening. In fact, if anything I was being overly cautious. The factory Ford top plates are in fact weak and cannot (with maybe the exception of the first or second time) stand up to the spec torque. I ended up with aftermarket ones from ATS and re-purchased the bolts (since you can't reuse them.) All went great the second time around.


Just an FYI for those doing this. Probably best to replace your top plates. Though, it seems to work out fine most of the time for most people. Or, maybe it doesn't and people just don't notice the bend. ATS did say this isn't uncommon - thus the reason they make aftermarket top plates.

 

I'd say it's more likely they are selling a product.

I've done quite a few axle swaps, and/or just playing with leaf springs on several 99-07 vintage and 80-97 vintage. Have never seen a top plate do that.


Glad you got her fixed up though