Wagz Posted October 17, 2003 Share Posted October 17, 2003 So, I am reinstalling my stub axles in the rear strut housings tonight and I'm having a hard time getting the big nut started on the first shaft. I got it started, but it's not moving freely enough. I visually verified that it wasn't cross-threaded, but I started to get a little pit in my shomach and backed it off. Sure, enough the firts couple of threads are slightly rounded-off. I tried another nut on the second shaft and was having the same difficulty so, I didn't push it. I just bought brand-new nuts from Victoria British to replace the stock peened nuts that I destroyed in removing them. I don't have anyway to accurately measure the threads on the nut or the shaft, but they to appear to be slightly different. I double checked my Vitoria Brithish catalog: All S30's from '70 to '78 take the same part number and the part number sent to me matches the catalog. I'm stumped and frustrated. Does anyone know if there were slight differences in the shafts? Anyone have a good source for these nuts? I'll probably head down to the nissan dealership tomorrow and see if they have some on hand. (wishful thinking) As long as I'm asking questions: Once, I have the nut issue worked out, does anyone know what pre-load specs I should torque these puppies to? Thanks! Quote Link to comment Share on other sites More sharing options...
denny411 Posted October 17, 2003 Share Posted October 17, 2003 Sears sells thread pitch guages that will give you # threads per mm. They can be found in the same area as the tap and die sets. If your new nuts are self locking, you should expect them to go on a bit tighter. Just be sure they have the same amount of threads per mm Quote Link to comment Share on other sites More sharing options...
blueovalz Posted October 17, 2003 Share Posted October 17, 2003 FYI, the 280zx nuts are the same size/pitch as well with the exception that they do not have the area to peen the nut onto the stub. The ZX nut (which I prefer) is a conventional locking flange-nut. Quote Link to comment Share on other sites More sharing options...
johnc Posted October 17, 2003 Share Posted October 17, 2003 What happens is that folks don't completely remove the peened over portion of the nut before removing it. That tends to damage/strip the last few turns of thread on the end of the stub axle. Then, when they try installing the new nut it gets cross threaded and they can't tighten it to the torque spec and have to throw the stub axle away. Buy a thread guage and a thread file and spend some time cleaning up the threads on the stub axle. Quote Link to comment Share on other sites More sharing options...
Wagz Posted October 17, 2003 Author Share Posted October 17, 2003 Thanks, guys. I suspect John is right. It's been over a year and a half since I removed the stubs. I remember that grinding the peened portion of the nut (without damaging the shaft) was a real pain in the a$$. I may very well have done a poor job in my hurry to just be done with it. I have a decent file for working on the threads. I'm going to do a little searching for a thread guage at some of the parts houses in my area (Sears is too much of a hike from my place). I also thought about stealing a little of my son's PlayDough to press into the treads of the nut and visually compare that to the undamaged portion of the shaft (poor man's thread guage ) Quote Link to comment Share on other sites More sharing options...
brokebolt Posted October 17, 2003 Share Posted October 17, 2003 JohnC is right, the original nuts are crimped on into the cut out area of the end of the shaft. So what to do if you don't have a set of 280zx Nuts on hand and Napa can't order them for you? Do this. First clean the shaft off the car with a good 4 inch hand grinder and a wire wheel or abrasive pad wheel to remove any bad areas on the shaft end. Next get a good rethread tool, M 20 X 1.50. I use one from my Snap-on set that I bought on-line RD-20. Next install the nut over the shaft and turn. I like to use tap-magic to help the tool glide over the threads. Unlike a die the rethread tool or thread restore tool will cram the remaining metal back into shape to help revitalize the old threads. If the metal will not comform back to shape the tool will remove it. A die will cut new threads in any metal that is there, their is a difference. This is only a fix to the issue of removing a nut that had not been properly preped before deinstallation. Am I am the worst person for not preparing the nut before removal. Best of luck. Mike Quote Link to comment Share on other sites More sharing options...
blueovalz Posted October 17, 2003 Share Posted October 17, 2003 Something that got me past this predicament was that I took one of these NEW nuts, cut it in half (so that you end up with 2 half-moon shaped pieces) so that each side could be pushed up against the GOOD threads of the stub (don't cross thread this step!). Then I placed this assembly (half nut-stub-other half nut) into a vise, and then slowlly turned the stub out of the bisected nut (e.g. unscrewed the stub from the nut). This restored the threads well enough so that I could start a new nut onto the the damaged threads. Be sure to clean up the nut's threads prior to putting them onto the stub. The cleaner the cut, the better it will work. Quote Link to comment Share on other sites More sharing options...
gramercyjam Posted October 17, 2003 Share Posted October 17, 2003 I learned the hard way not to assume VB sent you the right nuts. Check em with a thread gauge before putting an impact wrench on them Quote Link to comment Share on other sites More sharing options...
Wagz Posted October 28, 2003 Author Share Posted October 28, 2003 I ordered a rethread tool from Snap-On (thanks for the tip, Mike) and got the threads fixed on the stub axles. So, I just want to double-check the pre-load specs for the stub axle nut. My copy of the service manual says 3.9 inch-pounds. I believe this calculates to less than .4 foot-pounds. Is that correct? Less than half a ft/lb torque? Anyone know? Also, anyone have a recommendation for the best method to peen the new nut? Quote Link to comment Share on other sites More sharing options...
Wagz Posted October 28, 2003 Author Share Posted October 28, 2003 TTT Anyone? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 28, 2003 Share Posted October 28, 2003 I don't have a torque spec for you, but my ex-roommate and Nissan master tech always puts his impact gun on high and blasts away on them. That's how we did mine 6 years ago, probably 150 ft/lbs or 180 ft/lbs. I'm sure there is a torque spec, and I'm sure we did it the wrong way, but that's what he's done for a decade or more, and it seems to work. We peened the nut with a BFH and drift. One thing for sure, 1/2 ft/lb is not gonna cut it... Jon Quote Link to comment Share on other sites More sharing options...
gramercyjam Posted October 28, 2003 Share Posted October 28, 2003 That's how I do mine too. After that I "check" the toque with a 2' breaker bar and if I can still turn em, they aren't tight enough. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 28, 2003 Share Posted October 28, 2003 just off the top of my head, I think I remember the load being 180 ft lbs. Mark Quote Link to comment Share on other sites More sharing options...
johnc Posted October 28, 2003 Share Posted October 28, 2003 Rear axle bearing lock nut -25 to 33 kg-nm (181 to 239 ft. lb.) Quote Link to comment Share on other sites More sharing options...
Wagz Posted October 28, 2003 Author Share Posted October 28, 2003 Cool! Much thanks for the info, guys. I knew what I was reading had to be WAY wrong. Quote Link to comment Share on other sites More sharing options...
jt1 Posted October 29, 2003 Share Posted October 29, 2003 Bearing preload and the torque on the nut are two different things, but closely related. Basically you torque the nut to the point the bearings have enough preload (the clamping force on the bearings exerted by the nut) so that it takes 3.9 ft-# of torque to rotate the stub axle. The tighter the nut is torqued, the more it clamps on the bearings causing more internal friction in the bearing, and the harder the stub axle is to rotate. Bearings must have preload to function properly. The preload maintains the internal clearances and alignment when a working force (your car going around a corner) is applied to the bearing. If the bearing is loose and the applied force causes misalignment, the bearing life is short. A front wheel bearing is an excellent example of this. It's even more important with cone type bearings than ball bearings. John Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 29, 2003 Share Posted October 29, 2003 The preload on the rear wheel bearings comes from the spacer that sits in between the bearings. The spacer is not collapsable, so no amount of torque would change the preload. You're basically just making sure that everything is TIGHT. Or am I wrong? Jon Quote Link to comment Share on other sites More sharing options...
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