Steeda Differential Bolt Sheared Off on a NA car!!!

[TheLion]

I've been running the Red Steeda Differential bushing inserts for the past several months. I ran the same kit in my Ecoboost without any issues. But on my PP GT just yesterday (Sunday), when starting from a stop light I heard a loud "thunk" in the rear end. At first my wife and I thought maybe somebody tapped the rear end, so we pulled over and checked the car, nothing. Drove home and all seemed ok, I didn't notice at the time, but the car seemed a little "jumpy".

Well today I was going to install my FP Outer Toe Link Spherical Bearings, the last modification I had planned. Lo and behold the rear drivers side differential bold is GONE along with the red poly bushing support, all of which fell out some where on the highway after I took off from the stop lite. The end of the bolt is now stuck in the aluminum differential cover.

Tried drilling it and using a screw extractor but no dice. I'm seriously pissed at Steeda right now because of the massive amount of work and head ache their faulty part has caused me. This is not a 700~800 HP super charged drag car. It's NA 5.0 with just a Ford Performance Power Pack 2 and Corsa Sport Cat back exhaust making somewhere between 410~420 whp. Plenty of power to be fun to drive, but nothing over the top either.

I'm still on factory street tires for cryin out loud, Pirellie P Zeros as a matter of fact, which are NOT super sticky. I've never drone a drag launch and typically any hard use is on back roads in more of a "track style" type of driving, mostly 3rd and some 2nd gear. On occasion I do a 1-2-3 pull onto some back country highways from a rolling start. I'm gonna say it's absolutely ridiculous their hardware failed under these conditions.

Obviously the bolt fatigued over the last couple of month and then failed when I went to take off from a light. The bolts were torqued TO SPEC using a Tekton 1/2 drive torque wrench that is BRAND new and CALIBRATED. There is no way it was over torqued. I use torque wrenches on all drive train hardware.

I have no idea what they are going to do to make this right, but my only option right now is to swap differential covers. I still have my 3.31 diff from my ecoboost back when I did the 3.73 Torsen swap. Was going to throw it out but figured some day I might want to go FI and 3.31 might be a good gearing option.

Already have the sub-frame off the car, but haven't yet pulled the half shafts out of the diff. My big question is, what the heck socket do I use for those differential cover bolts? It' some odd-looking bolt head and it's not a typical 6 or 12 point. I haven't been able to find anything on what socket to look for to remove those bolts for the differential cover.

Any help would be appreciated. Hopefully steeda will do something to make this right. Dropping the entire sub-frame and swapping differential covers in a brand new GT with only 20k miles is NOT what I had in mind today when I went to start working on the outer toe link bearings and it's all because of a poor quality bolt that couldn't handle even a moderately tuned NA 5.0....pissed does not describe my feelings toward Steeda right now!

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[M151A2]

Not that I own Steeda products, I prefer BMR for no particular reason, I think you should give Steeda a chance to resolve your issue before bashing the snot out of them on this forum.

I surmised that the bolt sheared leaving the remains in the threaded portion of the differential. I have removed sheared bolts with very few problems. Now, with a cross threaded or corroded bolt, it is a different story.
I'm not suggesting anything other than the fact that you can't get the threaded portion out and it seems odd to me that a bolt that simply sheared would be such trouble to remove.

You will draw a lot more flies with sugar water than vinegar. Just sayin'

 

[TheLion]

Not that I own Steeda products, I prefer BMR for no particular reason, I think you should give Steeda a chance to resolve your issue before bashing the snot out of them on this forum.

I surmised that the bolt sheared leaving the remains in the threaded portion of the differential. I have removed sheared bolts with very few problems. Now, with a cross threaded or corroded bolt, it is a different story.
I'm not suggesting anything other than the fact that you can't get the threaded portion out and it seems odd to me that a bolt that simply sheared would be such trouble to remove.

You will draw a lot more flies with sugar water than vinegar. Just sayin'

The bolt has blue thread lock on it and was torqued to spec and has been through an entire winter with plenty of salt, so no, it's not coming out. What really frustrates me is that there was no reason for it to fail other than a quality issue. My GT is first and for most a street car, it's never been on a drag drip. All of my hard use is what can be safely done on public roads, so it's nothing nearly as extreme as what others are subjecting their cars to in actual track use.

This was a quality issue and instead of replacing just the part that failed, it has ruined a much more expensive and difficult to repair component along with it (namely the differential cover). I'm waiting to see what they are willing to do to make this issue right. I've used Steed, BMR, Ford Performance and Maximum MotorSports parts and so far Steeda's is the only one to have a part fail on me.

At this point the half shafts are out, the diff is out and now drained of fluid. On the bright side the outer toe link bushings came right out with a heavy duty ball joint remover and a 20 in long torque wrench (just set it to 250 ft-lbs and use it like a giant wrench).

Right now I'm just waiting for my Snap-On EPL 16 socket to come in the mail because I don't have one to remove the 10 Torx Plus bolts that hold the cover on to the housing. I also said what is @ Steeda going to do do make this right.Obviously the diff cover also serves as two of it's four mounting points and since the Steeda bolt threads are stuck in one side the cover is being replaced, or more specifically swapped out for the cover on my 3.31 diff I kept from the Ecoboost when I had it as the diff is the same.

Yes, I've used BMR parts as well, but I'm not partial to manufacturers. I go with whoever has the best parts for the job and BMR's 95 durometer bushings add a substantial amount of NVH, but steeda's 80 durometer bushings were a nice in between so I chose their kit for a street car application and I was completely satisfied with their performance up until Sunday night when the rear drivers side bolt sheared just starting from a stop lite, which now has me tearing down the ENTIRE IRS to do the repairs.

I'm glad only 1 bolt gave out and the others held up, which to me shows it was a faulty bolt. The other three managed to handle the torque load without giving out, or the damage could have been even far worse, destroying the drive shaft, CV joints and God knows what else.

 

[Brian V]

I am thinking that at some time during the past 3 years Steeda upgraded the bolts for the difff. . I guess you got the older set of bolts . I am a little spooked about this news .. I am sure going to be keeping an eye on me Diff .

 

[TheLion]

I am thinking that at some time during the past 3 years Steeda upgraded the bolts for the difff. . I guess you got the older set of bolts . I am a little spooked about this news .. I am sure going to be keeping an eye on me Diff .

As far as I know their standard kits still use grade 10.9 and they offer a grade 12.9 upgrade bolt set you buy separately that's intended for FI applications. 10.9 hardware should have been plenty so it's not that they picked out the wrong grade of hardware, it's the quality of the supplier they use to source their 10.9 bolts which obviously have had some failures as I've heard of a few others as well shearing diff bolts, but those were FI applications, not NA which I absolutely did not expect.

It's interesting that the bolt that failed was on the drivers side. The drivers side stock bushing is solid rubber, there's no "cushion" gaps in it like there is on the passenger side and both fronts. I wonder if that bolt takes more of the torque load from the diff than the rest of the bolts and I happened to put the defective bolt on that side. I'll be my bottom dollar had I put the bolts in the opposite sides I did it would not have failed....

12.9 is the highest grade hardness for Metric: https://www.boltdepot.com/fastener-information/materials-and-grades/bolt-grade-chart.aspx

10.9 is second highest and to my knowledge a stock GT uses all 10.9 on critical suspension parts, but no 12.9's unless it's aftermarket.

I'm really hoping Steeda will do something to help make this right. Not sure what, but something other than a cold shoulder and "too bad so sad" as this was a part quality issue.

 

[SteedaTech]

As far as I know their standard kits still use grade 10.9 and they offer a grade 12.9 upgrade bolt set you buy separately that's intended for FI applications. 10.9 hardware should have been plenty so it's not that they picked out the wrong grade of hardware, it's the quality of the supplier they use to source their 10.9 bolts which obviously have had some failures as I've heard of a few others as well shearing diff bolts, but those were FI applications, not NA which I absolutely did not expect.

It's interesting that the bolt that failed was on the drivers side. The drivers side stock bushing is solid rubber, there's no "cushion" gaps in it like there is on the passenger side and both fronts. I wonder if that bolt takes more of the torque load from the diff than the rest of the bolts and I happened to put the defective bolt on that side. I'll be my bottom dollar had I put the bolts in the opposite sides I did it would not have failed....

12.9 is the highest grade hardness for Metric: https://www.boltdepot.com/fastener-information/materials-and-grades/bolt-grade-chart.aspx

10.9 is second highest and to my knowledge a stock GT uses all 10.9 on critical suspension parts, but no 12.9's unless it's aftermarket.

I'm really hoping Steeda will do something to help make this right. Not sure what, but something other than a cold shoulder and "too bad so sad" as this was a part quality issue.

Just sent you a pm.

Steeda Tech

 

[wildcatgoal]

I had the red, then the black, then the aluminum. Then I through-bolted my IRS (which by the way added more NVH than popping in aluminum inserts).

This is my own assertion from installing these kits for some folks and closely assessing the design logic with long-time racers at my race club and shop (that I am a member of; I do not own a shop). When installing a compression fitted malleable part in this fashion, whereby it is filling a gap in a bushing that expands and contracts to some degree during normal operation, you absolutely need to recheck torque, especially immediately after your very first hard driving event when it is likely the added poly red or black bushing will be warm in temperature (and therefore likely to be ever so slightly more malleable under at least the kind of force coming out of your torque wrench) and will have done some settling in.

It's not necessarily that the BOLT moves (i.e., you used loctite), it's that the bushing insert can compress a little as it forms into the bushing with movement and the aluminum spacer insert will shift a bit, too. That could alter the actual pressure of the bolt/washer head (thereby reducing the amount of torque your bolt is tightened to. I also always use a light coating of suspension lube on the Steeda bushing insert when installing these so they seat perfectly by hand to prevent them from getting caught up on debris or just snagging due to friction -- all of which will quickly correct itself when the car is moving, thereby potentially changing your actual clamping force.

It all sounds wrong, sure. And yet I tell anyone I install these for to go drive their car like it was stolen for 20 minutes taking turns and launching and even trying to induce a little wheel hop. When they come back, I always get more turn out of the torque wrench before clicking on at least two of the bolts (usually the front two closest to the engine). You have to check torque on aftermarket parts, and not just one time. Check it often, especially after a drag or road course event. This does not mean you have a poor quality part, it means you need to maintain your vehicle with added care after you modify it. May not be the reason this happened to you, but it is A REASON it happens.

 

[15RRGT]

Hey man text me if you need any help with anything.

 

[TheLion]

It all sounds wrong, sure. And yet I tell anyone I install these for to go drive their car like it was stolen for 20 minutes taking turns and launching and even trying to induce a little wheel hop. When they come back, I always get more turn out of the torque wrench before clicking on at least two of the bolts (usually the front two closest to the engine). You have to check torque on aftermarket parts, and not just one time. Check it often, especially after a drag or road course event. This does not mean you have a poor quality part, it means you need to maintain your vehicle with added care after you modify it. May not be the reason this happened to you, but it is A REASON it happens.

I used a liberal amount of suspension lube on the bushings, so there was no sticking or improper seating. The bolts / washers compress against an aluminum center spacer, otherwise you would pull the bolt right through the bushing and deform the washer and have in adequate clamping force. I would not think it necessary to re-torque them, but then again you do need to re-torque lug nuts after about 100 miles.

But I digress, there IS text in the written instructions to re-torque after 100 miles. I must have missed that and it may be the cause of the failure. After speaking with Steeda, they recommend periodically re-checking them ever 3-4 months or after every track session as well. For a street / part time track car, that's a little more work that I'd like to do, so I may forgo the diff bushings as they are more critical to drag racing applications. Too many maintenance items can become a headache and it is NOT a dedicated track car. It's first and for most a street performance car that occasionally sees some track time for fun.

So I'll have to admit fault on not re-torquing them. There is no requirement on any of the factory diff bolts to re-torque them after x miles so it never came to mind, even if you remove it and reinstall it. Case solved. Steeda is kind enough to offer me a credit for the cost of the part even though technically it may have been an after installation maintenance error on my part.

Currently I have the entire IRS off the car and apart in my garage. I suppose on the bright side of things, the outer Toe Link Spherical Bearings I originally put the car up on stands to install are now in the knuckles. More or less I've created my own hybrid version of the Ford Performance "street / track handling pack". At this point I may not even put bushing inserts back in due to how they apply off axis force on the diff bolts.

Now the question is, what to do with the credit...

And word of the wise for anyone running Diff Bushing Inserts:

1. Re-torque after 100 miles
2. Re-torque every 3-4 months AND after every track event

Trust me, you don't want my headache. Yes, I've dropped an IRS before and done a diff swap (back when I had my ecoboost), so it's not a new adventure, but it's still a decent amount of work even with an impact wrench, two jacks, stands and a plethora of tools.

 

[Barrel]

My entire suspension is Steeda at this point. Sucks about your luck but I've done a lot of racing at a very high HP level on their stuff with no issues or failures, including their solid diff bushings. I wouldn't hesitate to give any of their products a glowing recommendation. I'm even installing their 2 two piece brake rotors here shortly.

 

[Brian V]

I went ahead and backed up on ramps and found that the drivers side front bolt needed to be re torqued to spec .

 

[GTP]

Seems like blue thread-lock is supposed to prevent having to re-torque...

@Brian V are you on OEM bolts or aftermarket?

 

[Brian V]

@GTP we are discussing the Steeda diff bolts .

 

[GTP]

@GTP we are discussing the Steeda diff bolts .

Yes, I know. But I don't know what is on your car. IOW, did you re-torque your OEM bolts, or do you have a Steeda set installed?

 

[TheLion]

Seems like blue thread-lock is supposed to prevent having to re-torque...

@Brian V are you on OEM bolts or aftermarket?

That is exactly what I would have thought. I'll use the wheel lug analogy to illustrate what we think MAY have happened (I still have some doubt and there is a real possibility of a faulty part): Lug nuts DO require re-torquing after 100 miles or so (no they don't have thread lock on them, but that's not why the requirement exists).

The initial clamping force is not enough to completely settle the wheel against the hub unless maybe it's literally brand new without a spec of rust or debris. After you get some corrosion during use, the surfaces are now high friction and some of the tolerance is eaten up by the rust particles that move and shift around during installation and even usage.

So the clamping force may not be adequate to fully seat the wheel by a few thousandths of an inch, typically after some use (heating and cooling cycles, vibration cycles) it settles and IF anything has shifted you'll know because you will be able to further rotate the lug nut at the same applied torque as before. I've had instances where the lugs didn't need re-torquing on one wheel, but a few others did on another wheel on the same car after 100 miles. It's hit or miss.

I also went through all of the Ford Performance shop manuals where the differential is removed (IRS ring and pinion swap, GT350 Diff cooler install instructions, Ford Performance differential bushing install), not one of them requires you to re-torque the bolts after x amount of miles. You install it and it should be good as long as you torque it to spec and used the supplied thread locker where needed.

Now Ford Performance does NOT offer poly differential bushings, only aluminum and they use factory grade hardware. It's possible that the poly bushings, because they do shift and move, are more susceptible to causing load changes that can loosen a bolt and may require a settling period just like wheel lug nuts. It's also a part that sees some decent temperature changes as the housing heats up and cools down during heavy use (especially torsens). Their entire limited slip capability is due to friction from the plethora of worm gears riding against the housing wall as the diff unloads, they begin to press harder and limit wheel slip. Then you have the diff oil, a cast iron and aluminum housing, all excellent for conducting thermal energy.

I'm going to say that the differential support bushings may be one area that adds significant shear stress to the bolts over the stock bushing setup. 1. The bolt is longer to accommodate the bushing and spacer and force is being applied further out towards the head of the bolt due to the bushing contact area with the factory bushing shell 2. There is less compliance in the bushing than the original design 3. harmonics have also changed and may impact bolt torque 4. The bolt, while also a class 10.9, is NOT the same as the factory bolt. It is a different supplier than what Ford uses.

I believe the factory bolts are made to custom OE specs in terms of class, material, plating, physical dimensions, QC etc. The factory bolts certainly seem far more corrosion resistant than the Steeda nickle or zinc plated hardware which corrodes fairly rapidly from road salt, so for those in a 4-season state, you may want to consider longer term durability if you drive on salted roads as well. Fluid film or exhaust paint might work as a good rust inhibitor.

It is my guess that due to the design, that the after market bushing inserts require periodic maintenance while factory hardware DOES NOT. At least not this particular offering. It's not necessarily a bad design, it's just not something I am personally willing to mess with. To me it's a big liability from a reliability standpoint, so until the car is retired for pure fun, right now it serves double duty as our Grand Touring car / Fun car, low maintenance / high reliability is my first priority over performance.

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