Stunt Posted March 10, 2015 Share Posted March 10, 2015 1971 240z with 280z motor. I just finished swapping my motor and tranny into the car. I think I accidently cross threaded the frame nut for the tranny crossmember. What could I possibly do to resolve this issue? Quote Link to comment Share on other sites More sharing options...
johnc Posted March 10, 2015 Share Posted March 10, 2015 Remove the bolt, buy a new one, and run a tap though the threaded nut in the chassis. Quote Link to comment Share on other sites More sharing options...
Stunt Posted March 11, 2015 Author Share Posted March 11, 2015 Ok. I'll try that. Quote Link to comment Share on other sites More sharing options...
Stunt Posted July 19, 2016 Author Share Posted July 19, 2016 It was actually the left transmission tunnel ear. Seems like it is floating nut inside the transmission tunnel ear. How can I fix this? Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 19, 2016 Share Posted July 19, 2016 Remove the bolt, buy a new one, and run a tap though the threaded nut in the chassis. ^^^^^^!^^^^^^ Quote Link to comment Share on other sites More sharing options...
Stunt Posted July 19, 2016 Author Share Posted July 19, 2016 It was actually the left transmission tunnel ear. Seems like it is floating nut inside the transmission tunnel ear. How can I fix this? Quote Link to comment Share on other sites More sharing options...
Stunt Posted July 19, 2016 Author Share Posted July 19, 2016 The nut seems to be a floating type. Is it safe to do so or am I screwed? Quote Link to comment Share on other sites More sharing options...
NewZed Posted July 19, 2016 Share Posted July 19, 2016 Aren't you screwed right now? You'll be in the same state, but at least you'll have tried something. http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-240z-260z/engine-mounting/manual-from-c-hls30-46001-rls30-grls30 Quote Link to comment Share on other sites More sharing options...
Stunt Posted July 19, 2016 Author Share Posted July 19, 2016 (edited) I have the vertical bolt crossmember like this. http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-240z-260z/engine-mounting Edited July 19, 2016 by Stunt Quote Link to comment Share on other sites More sharing options...
seattlejester Posted July 19, 2016 Share Posted July 19, 2016 The floating nut is square so it doesn't rotate. Start the tap once it grabs you can rethread it. If that doesn't work you are going to have to get at the nut (I am guessing either a nut on a plate or a thread piece of plate), remove it, and put in a new one. If you look from the inside on the trans tunnel you can see where the spot welds are. You can cut a bit of it out and try to fish it out, or you can drill out the spot welds and have someone weld it back in for you after you replace the nut. Quote Link to comment Share on other sites More sharing options...
NewZed Posted July 19, 2016 Share Posted July 19, 2016 People have had your problem. You just need to find the nut from inside the car and replace it if you can't fix it from below. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 20, 2016 Share Posted July 20, 2016 It's funny how someone repeats the same question over because he doesn't like the answer he's been given. I retapped mine EXACTLY as JC suggested and had no issues with the "floating nut"... What is the big problem here? Why can't you do this? As seattlejester suggests above, get the tap started straight and once it grabs you're home free. This is not rocket science. Quote Link to comment Share on other sites More sharing options...
Stunt Posted July 20, 2016 Author Share Posted July 20, 2016 Sorry I accidentally forgot to erase my old reply. I will try to tap the frame nut. Quote Link to comment Share on other sites More sharing options...
Stunt Posted July 25, 2016 Author Share Posted July 25, 2016 I tried to tap the floating nut in the transmission ear and failed. Quote Link to comment Share on other sites More sharing options...
NewZed Posted July 25, 2016 Share Posted July 25, 2016 That's a shame. You'll be parting the car out now? Failed in how to use a tap? Broke the tap off in the nut? The nut turned with the tap? Used the wrong thread pitch? Just kidding. You're not really asking a question anyway, just reporting a result. Quote Link to comment Share on other sites More sharing options...
Stunt Posted July 25, 2016 Author Share Posted July 25, 2016 I'm just gonna take it a shop that will fix it. I just wanna drive my car already. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted July 25, 2016 Share Posted July 25, 2016 ... If you broke the tap in the nut the shop is going to have to cut into the car to extract the whole plate and replace it. They would need a metric tap and dye set, an angle grinder, a welder, metal stock, and a drill press. That is going to require a very different shop from if you just don't know how to use a tap. This is also going to cost you a bit to tow the car since driving with just one side of the trans cross member is going to stress the crap out of the cross member. You are looking at a very expensive situation. Quote Link to comment Share on other sites More sharing options...
Stunt Posted July 26, 2016 Author Share Posted July 26, 2016 I'm gonna attempt to to cut out a slit of metal and swap the floating nut and have a friend weld back the piece. Wish me luck. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 27, 2016 Share Posted July 27, 2016 No information, no way to render aid. Broken tap I. That nut plate is NOT a cut and remove issue! Take the tap you broke to a grinder, make a bluntish flat-chisel out of what remains, taper it slightly so the thing is maybe 6-8mm wide with a 2mm wide "chisel" edge...flat and blunt. Put on your safety specs, hold it in a vice grips and put it in the center of the cross of the broken tap....RAP smartly with a 16oz hammer. The broken tap will shatter/break off the cutting flutes and be out of your hair to try again. This takes about 15 minutes including swearing and composing Oneself to the inevitable and grinding the remains into a suitable tool. Throw it in your box, it will come in handy later till you get the feeling of how to properly use a tap and lubricant. Quote Link to comment Share on other sites More sharing options...
Stunt Posted July 27, 2016 Author Share Posted July 27, 2016 (edited) I did not break the tap. I used a drill with the correct next size 10x1.25 as an extension. Basically made the hole too big without thread. The tap set I have, did not have longer taps. The tool would not have been able to move since the taps are so short. The tool was so short I could not turn by hand. The tool would touch the floor board without me actually centering it. That's why I used an electric cordless drill and try to do slowly. In the end I messed up. Now I regret my actions. I don't want to give up and sell or part out my car. I've invested too much money to let this project go. Should I just source a parting out series 1 Z car and have the body shop drill out the spot welds on both? Replace the bad ones with the new. Edited July 27, 2016 by Stunt Quote Link to comment Share on other sites More sharing options...
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