Stripped Subframe Nuts Nightmare - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

apex128 · 04-16-2017, 06:43 PM

Hello,
I have been trying to install my ES subframe and differential bushings and it has been giving me a lot of trouble. All the bushings went in easily, but when it was time to reinstall the differential into the subframe, one of the holes simply would not line up. It was very close, but I could not get the bolt in. To make things worse, both bolts and their holes holding the diff to the subframe are now stripped out, and it is very difficult to get the holes to line up in order to bolt in the diff. Basically what I want to know is if it is okay to just drill through the subframe and put a nut on the end on the other side. Would this be strong enough to hold the diff securely? What other options do I have? The holes I am talking about are pictured below.

apex128 · 04-17-2017, 07:00 AM

Bump. Trying to get my car back on the road

tuzzio · 04-17-2017, 08:02 AM

Why not just tap new threads

s13silvia123 · 04-17-2017, 08:20 AM

you can tap into new threads first. if that doesnt work drill through by tack weld the nut or use flat and lock washer with nut.

travon47 · 04-17-2017, 10:08 AM

s14 subframes have floating square nuts that are not welded to the subframe and allow a decent amount of movement so not sure why you are having issues lining it up? Maybe they are rusted together and not allowing movement? Atleast this is how my 98's subframe is. My subframe doesn't have the extra metal in front of the front subframe mounting points like in the picture though so maybe its different. Either way if you stripped them out bad enough to not be able to re tap them I would get a hole saw and open up above each nut and see whats going on inside and go from there. If you just put a nut on the other side you will have to pull the subframe out everytime to change the diff to have access to the nuts you put in, and you wouldn't be able to re weld and close up where you hole sawed because you need access to the nuts and not doing that might compromise the integrity of the subframe. Maybe if you drill out the nut that's in there and weld another nut on top of it so you can close up the hole saw hole it would work. just make sure your bolt is long enough to do that. If you do open it up, I want to see pics lol

*dbeiler* · 04-17-2017, 06:16 PM

You need to be very careful whenever you install those forward diff bolts. The diff needs to be as far upward and rearward as possible before attempting to start the bolts. Thread the bolts in by hand at least halfway before even thinking of touching them with a tool.

This is a very simple fix. Buy an M12 x 1.25mm Helicoil kit and two new Nissan diff mounting bolts. Drill out the stripped nutplates with required drill bit. Install the Helicoils into the original nutplates. Install new bolts. No need to remove or destroy the subframe. Should take maybe 15 minutes per nutplate.

*dbeiler* · 04-17-2017, 06:18 PM

Quote:

Originally Posted by travon47

My subframe doesn't have the extra metal in front of the front subframe mounting points like in the picture though so maybe its different.

Those are vibration dampers found only the manual (or automatic??) transmission model subframes.

apex128 · 04-18-2017, 09:09 AM

I already drilled the holes and have 8 in bolts that will go all the way through the subframe. I thought about doing the helicoil, but the bolt holes still won't line up if I do that. My lsd was installed by a dealership, so I think they may have messed something up on the subframe. (Pretty sure they cross threaded the bolts). Do you think it will be okay to bolt it all the way through, despite the fact that the subframe is a curved surface? Will just a lock washer and flat washer be enough when bolting to a surface with this amount of curve? I will be using all grade 8 hardware.

apex128 · 04-24-2017, 07:56 AM

Update:
I put everything together as described above, and the subframe was being pushed in a little bit as I tightened. To circumvent this, I made a large washer out of a metal plate to distribute the load more evenly. That bent a little too, but I think it will be fine. Bolts were torqued to 85 ft. pounds. If I were to do it again I would have probably just used a helicoil.

04-16-2017, 06:43 PM	#1
apex128 Zilvia Member Join Date: Jul 2016 Location: Chicago suburbs Posts: 173 Trader Rating: (0) Feedback Score: 0 reviews	Stripped Subframe Nuts Nightmare Hello, I have been trying to install my ES subframe and differential bushings and it has been giving me a lot of trouble. All the bushings went in easily, but when it was time to reinstall the differential into the subframe, one of the holes simply would not line up. It was very close, but I could not get the bolt in. To make things worse, both bolts and their holes holding the diff to the subframe are now stripped out, and it is very difficult to get the holes to line up in order to bolt in the diff. Basically what I want to know is if it is okay to just drill through the subframe and put a nut on the end on the other side. Would this be strong enough to hold the diff securely? What other options do I have? The holes I am talking about are pictured below.

04-17-2017, 08:20 AM	#4
s13silvia123 Post Whore! Join Date: May 2006 Location: where waldo is Age: 39 Posts: 3,256 Trader Rating: (16) Feedback Score: 16 reviews	you can tap into new threads first. if that doesnt work drill through by tack weld the nut or use flat and lock washer with nut. __________________ 18g and 20g turbo users click on me http://zilvia.net/f/tech-talk/261219-18g-20g-turbo-users.html

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04-17-2017, 07:00 AM	#2
apex128 Zilvia Member Join Date: Jul 2016 Location: Chicago suburbs Posts: 173 Trader Rating: (0) Feedback Score: 0 reviews	Bump. Trying to get my car back on the road

04-17-2017, 08:02 AM	#3
tuzzio Nissanaholic! Join Date: Oct 2013 Location: Western Mass. Posts: 2,254 Trader Rating: (3) Feedback Score: 3 reviews	Why not just tap new threads

04-17-2017, 10:08 AM	#5
travon47 Leaky Injector Join Date: Aug 2007 Location: Minneapolis, MN Age: 31 Posts: 93 Trader Rating: (0) Feedback Score: 0 reviews	s14 subframes have floating square nuts that are not welded to the subframe and allow a decent amount of movement so not sure why you are having issues lining it up? Maybe they are rusted together and not allowing movement? Atleast this is how my 98's subframe is. My subframe doesn't have the extra metal in front of the front subframe mounting points like in the picture though so maybe its different. Either way if you stripped them out bad enough to not be able to re tap them I would get a hole saw and open up above each nut and see whats going on inside and go from there. If you just put a nut on the other side you will have to pull the subframe out everytime to change the diff to have access to the nuts you put in, and you wouldn't be able to re weld and close up where you hole sawed because you need access to the nuts and not doing that might compromise the integrity of the subframe. Maybe if you drill out the nut that's in there and weld another nut on top of it so you can close up the hole saw hole it would work. just make sure your bolt is long enough to do that. If you do open it up, I want to see pics lol

04-17-2017, 06:16 PM	#6
dbeiler Premium Member Join Date: Jun 2012 Location: Lancaster county, PA Age: 30 Posts: 465 Trader Rating: (4) Feedback Score: 4 reviews	You need to be very careful whenever you install those forward diff bolts. The diff needs to be as far upward and rearward as possible before attempting to start the bolts. Thread the bolts in by hand at least halfway before even thinking of touching them with a tool. This is a very simple fix. Buy an M12 x 1.25mm Helicoil kit and two new Nissan diff mounting bolts. Drill out the stripped nutplates with required drill bit. Install the Helicoils into the original nutplates. Install new bolts. No need to remove or destroy the subframe. Should take maybe 15 minutes per nutplate.

04-18-2017, 09:09 AM	#8
apex128 Zilvia Member Join Date: Jul 2016 Location: Chicago suburbs Posts: 173 Trader Rating: (0) Feedback Score: 0 reviews	I already drilled the holes and have 8 in bolts that will go all the way through the subframe. I thought about doing the helicoil, but the bolt holes still won't line up if I do that. My lsd was installed by a dealership, so I think they may have messed something up on the subframe. (Pretty sure they cross threaded the bolts). Do you think it will be okay to bolt it all the way through, despite the fact that the subframe is a curved surface? Will just a lock washer and flat washer be enough when bolting to a surface with this amount of curve? I will be using all grade 8 hardware.

04-24-2017, 07:56 AM	#9
apex128 Zilvia Member Join Date: Jul 2016 Location: Chicago suburbs Posts: 173 Trader Rating: (0) Feedback Score: 0 reviews	Update: I put everything together as described above, and the subframe was being pushed in a little bit as I tightened. To circumvent this, I made a large washer out of a metal plate to distribute the load more evenly. That bent a little too, but I think it will be fine. Bolts were torqued to 85 ft. pounds. If I were to do it again I would have probably just used a helicoil.