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280zx axle stub nut help


69sroadster

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Hey all...the book doesn't say anything special about this crazy nut, but is it reverse threaded? I've got a slightly bent axle stub and I cannot get this crazy nut to break loose to save my life. I've bought a crazy 700+ ft lb 1/2 drive torque gun and that couldn't budge it. I've used a breaker bar with a hydraulic jack under it while having my wife step on the brakes and it just kept lifting the tire higher off the ground and still seemed to override the brake a bit. I'm running out of ideas. Is this out of the ordinary for these retaining nuts? What else can I do to get it free?

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I was kinda hoping you'd say otherwise and I could go out there and get it free in just a few pulls...too bad I'm back to finding other creative ways to put more torque on that frikin lock nut. Time to get a very large pipe I guess and maybe find another way to keep the stub axle from moving any more. Thanks though.

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I've been soaking it with WD40 and will reattempt again later on the nut. Since I'm swapping the 280zxt cv axles into an N/A 280zx, do I also need flanges for both sides of the cv axle? I have the outside flanges for the stub axle to cv. I don't have a turbo service manual and believe me or not I could not find a good picture of an installed turbo cv setup that shows the inner side into the diff. I think I may have had a wrong idea in my head for some reason that because my N/A setup has a separate input shaft into the diff that the 280zxt did too. It looks like to me that the 280zxt cv shaft just goes straight in to the diff without an intermediate flange like the N/A 280zx has. Anybody with a turbo 280zx out there can help straighten me out on this?

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I did both yesterday, couldnt use my hands but it wasnt that bad.... :)

 

Anyways jack up the car enough to slide under but enough that the wheel is still in contact with the ground where it wont spin. For the driver side I just got a 1/2 socket (about a foot long) and slipped it on the nut (no extension!) and then from the back of the car brace yourself and use your foot to push on the socket wrench (socket wrench pointed to the ground). As said it takes alot, just imagine 200 ft/lbs, thats around 200 lbs to be applied on the wrench. For the other side youll be lying under the rocker panel applying force the same way as before but its alittle easier since you can brace yourself up against the front wheels.

 

Sorry if I explained something that is equivalent to just "use your foot". haha

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Challenger no worries that made me laugh a bit at the end. I did try something pretty aggressive and I'm surprised it didn't work. I left the car on the ground, chocked the tire, set the e-brake, and had my wife stand on the brake pedal. Then I put the 1/2 drive 18" long breaker bar on the nut and started jacking up the end of the breaker bar with a floor jack. The bar was bending and slowly the spring/shock started to compress and the car slowly lifted up a little in the end too, followed by slight rotation of the tire. My next step is to put a 4' long pipe over the breaker bar and another long bar between the lug studs. If that doesn't work then I have a concrete lug bolt and chain in my garage floor that I'll use to try pulling the bar down vs pushing it up to keep weight/traction on that tire from turning. I can only imagine how much this is putting on that stinkin' nut so far.

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Dont try pulling up on it, as you found its just going to compress the suspension. You have to apply a force to somewhere it wont make the suspension move, that would be along the length of the car. When you push on it from the front or back (depending on if the wrench is pointing up or down) the suspension has nowhere to go.

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QUOTE: What else can I do to get it free?

The threads are NOT reversed. Get an impact gun. If you don't have air, an electric one will work. You are going to mess around and pull the car off the jack stands and cause problems if you continue along your present path. You may be able to borrow a gun from an auto store loaner program. Have fun!

Edited by Mayolives
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On my '73, the nuts were staked, but I don't believe yours are as they probably use a lock nut, but I would check.

 

If you absolutely can't get it, I think the last ditch effort would be heat, but you have to be careful not to heat the bearings too much.

 

On my car, I had a hell of a time too, except when I figured out I have to cut off the right in which the nut was staked, it was a piece of cake!

 

Good luck man!

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Yeah I agree with not pushing up anymore against the suspension compression and will try the pull down method instead. BTW I already tried what was supposed to be a Craftsman Professional 1/2" drive impact gun rated at 750ft/lb & 90 psi...it didn't do anything. I'll check into the staked nut too but I don't think it is.

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Yeah I agree with not pushing up anymore against the suspension compression and will try the pull down method instead. BTW I already tried what was supposed to be a Craftsman Professional 1/2" drive impact gun rated at 750ft/lb & 90 psi...it didn't do anything. I'll check into the staked nut too but I don't think it is.

 

Craftsman is lying. I know of no 1/2" drive impact gun that will generate 750 ft. lbs. forward much less reverse. You need at least a 3/4" drive gun to get near that torque number. If you check the "working torque number" (the actual torque the gun puts out) you'll find your gun is in the 300 ft. lb. range. I have that exact gun in my shop.

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JohnC I don't doubt that one bit. It sounded inflated to me, but I decided to run the line pressure up about 20 psi higher and just let it go longer than the recommended 5 sec max. It seemed like it was making some really slow progress so I let it run for about 30 sec at a time. Bottom line is that it finally did get the darn thing off. Now the interesting thing is that the axle stub doesn't appear to be bent, sheared, broken etc like I thought it was. The symptom was wheel wobble to begin with which you could see watching the axle stub turn. I now suspect that the outer wheel bearing or distance piece is suspect. Before I disassembled the bearings felt tight. I disassembled it and after finding no apparent faults in the axle stub itself installed it all back together w/o torquing the nut back on. Now it looks like it's rolling true but the bearing feel like they have play up/down, fwd/aft. Do I need to torque the nut back down to check the bearings again? This is getting a little interesting now.

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My brother has a snap on gun thats huge, most power ive ever used. If you put the line pressure up to full resevoir pressure, then stick gun lube in the fitting, and i mean extra, it really gets extra power to it. Dont do it too much as you could blow out the seals. 30 seconds isnt much, go more. Heat the nut as well, even a propane torch will help. The nuts in the 280zx have a metal tab bent over the side of the nut, its very hard to see, but it needs to be bent down, or the nut wont move. The gun is the best solution as you dont need much to hold the other side. The more things you stick on it to hold things, the more chance of you or others getting hurt there is. I am a proffessional mechanic, and sometimes these things show up, and the customer expects it, so brute force and using a tool SLIGHTLY beyond its normal limits is required. Thats why tools have warranty. :)

Edited by SHADY280
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My brother has a snap on gun thats huge, most power ive ever used. If you put the line pressure up to full resevoir pressure, then stick gun lube in the fitting, and i mean extra, it really gets extra power to it. Dont do it too much as you could blow out the seals. 30 seconds isnt much, go more. Heat the nut as well, even a propane torch will help. The nuts in the 280zx have a metal tab bent over the side of the nut, its very hard to see, but it needs to be bent down, or the nut wont move. The gun is the best solution as you dont need much to hold the other side. The more things you stick on it to hold things, the more chance of you or others getting hurt there is. I am a proffessional mechanic, and sometimes these things show up, and the customer expects it, so brute force and using a tool SLIGHTLY beyond its normal limits is required. Thats why tools have warranty. :)

 

Thanks to everyone's inputs. The craftsman impact gun did finally break the nut free. It was really really slow going at first and I had to look closely to see if it was really doing anything the first few trys. The other side of the car was SO much easier to break free with the same gun. The left side (easier one) was never taken apart before and the right side (pain in the @$$) had a wheel bearing replaced a long time ago. It makes me thing that someone over-torqued the nut when they reinstalled the assembly.

 

I also noticed the ZX book mentions not to reuse the bearings and nut. Is it a one time stretch nut? The whole point of this tear down was to repair a wheel wobble thinking the axle stub was starting to shear due to SCCA racing with the SR20 and 17x9" rims. The axle stub looks fine after removal and the bearings are all tight. I couldn't figure it out but now after putting it all back together again I noticed that if the axle stub appears to be seated all the way in, then it feels like the bearings aren't lining up on the axle giving me the free play. When I back the axle stub away about 1/8" then it feels like the bearings seat on the axle and I get no wobble. What would cause the bearings not to line up on the axle stub properly? I've got a good distance piece in there, bearings appear to be seated completely in the hub making contact with the distance piece, and a good outer spacer. Is it possible for the bearings to appear to be seated when they're not? Is the distance piece too long maybe? I'm at a loss why this would happen suddenly one day when it's been fine for so long.

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It was the stub axle that was bad after all on the right side causing the wheel wobbling. I had to take out the left side stub axle which was fine in order to replace the bearings starting to go and I temporarily tried it out on the right side...no problems. I think the inner seal on the left side started failing a while ago since there was some slight surface rust and it was a pain in the butt to slide out. I should be able to put it all back together later tonight and hopefully get the car back on the road again, yeah!

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So the car is back up on the road again and driving smoother than it was a few years ago. I must have had a problem for a long time without realizing it. Thankgs Greg for the ZXT CV's and stubs. I didn't know how much I missed driving my Z until I took it to work again yesterday. I should be getting some better video this next SCCA meet in a few weeks to post/share. Anyone who wants to talk about SR swaps can feel free to PM me about what all is entailed. So far I'm still loving it.

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  • 10 months later...

Just though I'd mention how I got one of these off today...Although this is more of a junkyard technique. I wedged a breaker bar on the nut and since the wheels were off I put a crowbar through the wheel bolts and had to jump on the end a few times ( I weigh 200+ lbs) and it came loose. It was pretty fun and I think it's great for a junkyard but I'd be afraid to do that to my own car. Hope this helps someone.

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Just though I'd mention how I got one of these off today...Although this is more of a junkyard technique. I wedged a breaker bar on the nut and since the wheels were off I put a crowbar through the wheel bolts and had to jump on the end a few times ( I weigh 200+ lbs) and it came loose. It was pretty fun and I think it's great for a junkyard but I'd be afraid to do that to my own car. Hope this helps someone.

 

Yep, I use a 4' long pry bar. Make sure you put the lug nuts back on so you don't damage the threads. I then use a standard 1/2" breaker bar like you did and use the 4' bar to break the nut free. I've never had one not come off. Of course, you must remove the penning on the nut first or the threads will be destroyed.

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