Help needed - possible cross-threaded rear subframe attachment bolts

[esb]

I have a 2021 GT convertible w/PP. I am in the process of installing the Steeda rear subframe alignment Kit and rear subframe bushing support kit. Everything was (mostly) going fine when I got to installing the last subframe bolt (driver side / front bolt). I started it by hand and it starts threading OK, but after a couple of turns it binds up completely. The only torque I applied was a brief attempt with a ratchet to see if the binding was easy to overcome (say due to additional friction/side load from the centering dowels). Unfortunately that doesn’t appear to be the case. While doing all of this I have the subframe supported by a jack just behind the toe link so I don’t have any weight on the bolts when getting them started. I then lowered that side of the subframe again and removed the dowel to see if there was an angle where I could thread the bolt in. Unfortunately no matter what I do I can’t get it to thread beyond those first couple turns. It seems like the bolt may have been cross-threaded at the factory (or possibly by the previous owner).

Any suggestions on what to try next? It looks like the factory bolts are even notched for the first few threads that appear to be intended to either cut new threads or clean out the threads as it’s screwed in. I’m very leery about putting any real torque on the bolts for fear of making it worse. Do I need to get a tap and try to chase the existing threads (or re/cut them)? To do that, I think I’m going to have to drop the whole rear subframe as the bushing doesn’t appear to drop far enough for me to get a tap inserted. And to do that, I’m guessing I need to remove the exhaust at a minimum. Will I need to disconnect the drive shaft as well? I already have the brake calipers removed (for painting) and can detach the shocks (again).

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[Swtbabybilly]

If u could provide some pictures that would really help, personally before anything I would try blowing the hole out with air, blast the threads with something like wd40 and work the bolt in and out of the hole by hand alittle further each time and check the threads on the bolt see if they look rounded off or just full of crud, best of luck man

 

[esb]

I did go and get a M14x2 tap and was able to chase the threads without dropping the whole rear subframe. I just used a pair of pliers to turn the tap and after only 6-8 rotations I was able to thread the bolt in by hand without binding. Now the problem is that the centering dowel doesn't line up with the hole. I think I'm going to have to shift the subframe a bit (hopefully) without misaligning any of the other holes.

 

[Swtbabybilly]

Leave all the bolts in just loosen them up alittle so you can shift the subframe with a pry bar and not lose alignment on any of the holes you already caught bolts in

 

[esb]

Also, for reference, this is a good thread on the same issue:

https://www.mustang6g.com/forums/threads/help-rear-subframe-bolt-cross-threaded.53350/page-7

It seems like the consensus is to lower the entire subframe a bit with a jack (at most an inch or so). With all 4 bolts loose, thread in both front bolts first followed by the rear bolts.

That said, 3 of the 4 bolts went in just fine with the centering dowels. It's just the 4th that doesn't line up (front driver's side). Given that with the dowels there is very little play, I don't know if I'll be able to get the 4th in. I'm guessing factory tolerances are loose enough that some cars just won't be able to have the centers of all 4 holes align, hence the likely reason for such a large diameter hole through the bushings.

 

[GL95]

Highly recommend these

https://www.kelltrac.com/IRS-Subframe-to-Chassis-Stud-Kit_p_24.html

 

[GTP]

IMO the steeda dowel holes are just a bit tight and I've heard that the BMR product either has softer material or larger holes or both.

Also don't forget that the (Steeda) hole diameter is slightly larger at one end and that end should be pointed down so as to better clear the knurling under the bolt head.

You are not the first to get in 3 but not 4.

 

[Snellemin]

Also don't forget that the (Steeda) hole diameter is slightly larger at one end and that end should be pointed down so as to better clear the knurling under the bolt head.

You are not the first to get in 3 but not 4.

Happened to me. Used a tap to clean out the threads and bought new bolts from Ford. Loosened all the bolts and the subframe aligned perfectly.

 

[John S]

Those centering bushings are hit or miss if they’ll match up with the body’s threaded inserts. The cradle holes are large to accommodate positioning adjustments to optimized cradle alignment with the body. My son’s car had three centering bushings match the body’s threaded inserts and my Mach 1 had only two that aligned with the body interface.

 

[SheepDog]

Also, depending on how far off the cradle was to begin with in regards to the alignment of the holes in the subframe vs. the holes in the body, you may not be able to get your thrust angle back into spec. Be sure to get an alignment afterwards.

x2 on the Kelltrac subframe stud kit

 

[esb]

Thanks for the advice everybody. I was able to get that final bolt to line up by applying a bit of leverage with a pry bar. It definitely helps to have a 2nd set of hands for that.

I've also ordered the Kelltrac subframe stud kit. That will make this easier in the future and avoid further risk to the threads

 

[Mikepol2]

I'm about to do this same mod (Steeda subframe lockouts and UPR alignment sleeves) and really don't see any reason that more than 2 of the 4 sleeves would be necessary. If their only purpose is to align the subframe to the car, then once you get 2 in, there's nowhere else for the subframe to go, and you're at the mercy of manufacturing tolerances stackups between the body and the subframe for the other two. Zero benefit and high likelihood of what OP and many others have experienced.

 

[pinksurfer]

I'm about to do this same mod (Steeda subframe lockouts and UPR alignment sleeves) and really don't see any reason that more than 2 of the 4 sleeves would be necessary.

I had all of the same issues others here had. front drivers hole was stripped-VERY common and thanks to kelltrac for sending a tap/studs as a last minute gametime decision. would advise ordering beforehand to anyone thinking of this mod. couldn't get all 4 steeda bushings in. I thought along the same lines Mikepol did as once I had the 2 front ones in, where is the irs going to go? spent 2 days and 4 or 5 hours trying to get the 4th one in and gave up settling on 3.

 

[GTP]

This issue has come up many times. My instinct is that a looser tolerance on the sleeves (=larger bore I.D.) could very well alleviate the problem. And I don't believe the error in alignment would be significant at all. So, consider a 15mm (or 9/16 to 5/8") drill bit and drill press, or lathe.

Removing the sleeves can also be tricky. I put dry lube on the outside of mine to help.

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