Jersey Posted March 31, 2004 Share Posted March 31, 2004 Hey all. I'm sure this info is posted here and other places on the net but, i just wanted to make a reminder post for anyone considering using the CV halfshafts in a 280 by installing the 240 stub axles into the 280. Make sure you use the 240 bearing spacer!!! The 280's spacer is about 1mm longer than the 240's and will bind against the bearings when the companion flange nut is properly torqued down to spec, causing the wheel to be completely locked up. I scratched my head for over 2 hours last night because i SWORE i had the spacers side by side and they were exactly the same, but they're not. A one hour job took me nearly 3 hours because i missed this and wouldn't want anyone else to go through my pain and suffering!!! lol. Quote Link to comment Share on other sites More sharing options...
johnc Posted March 31, 2004 Share Posted March 31, 2004 Well... the bearing spacer is designed for the hub the stub axles are installed in. Although I've never swapped 240 stub axles into a 280 hub, I've done the reverse and used the "B" spacer that almost always comes with thr 240/260Z hubs. I wonder if the 240Z stub axle is shorter then the 280 stub axle? Maybe you over torqued the stub axle nut? The manual says to torque the nut to 140 ft. lbs. and then measure the bearing preload with a spring scale pulling on one of the wheel lugs. Keep increasing the stub axle nut torque until you get a reading of 25 to 30 ounces on the spring scale. Then stake the stub axle nuts. Quote Link to comment Share on other sites More sharing options...
Jersey Posted March 31, 2004 Author Share Posted March 31, 2004 The 240 stubs have to be a be a bit shorter, between the bearings anyway, by about the 1mm. Both the 240 and 280 different sized spacers had a "B" stamped on them. I torqued them correctly. Once i used the correct 240 shorter spacer, it was perfect. It will not work with the longer 280 spacer. I'm not sure if there's any ill effects of what you did by using the shorter 240 spacer on the longer 280 stub but, i'm sure you wouldn't notice the binding effect like i did after installing them! haha. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 31, 2004 Share Posted March 31, 2004 OK, because I am currently looking for 280 stubs, I am interested in this. John, are you saying that with my 280 stubs in 240 struts that I should use the 240 spacer? Seems like Jersey's experience would lead a person in the opposite direction, so that the spacer goes with the stub axle into whatever strut is used. Jon Quote Link to comment Share on other sites More sharing options...
johnc Posted March 31, 2004 Share Posted March 31, 2004 I'm running 280 stubs and companion flanges in my 240 hubs and I ran the spacer that came with the hub (didn't have the 280 spacer). I used the installation procedure listed in the manual and ended up with something like 205 ft. lbs. of torque if memory serves me. I don't think think the stub axle length is different, but there may be differences in the 25 spline and 27 spline companion flanges. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 31, 2004 Share Posted March 31, 2004 OK, so it looks like the key is really the bearing preload. Thanks. Quote Link to comment Share on other sites More sharing options...
johnc Posted March 31, 2004 Share Posted March 31, 2004 And why is this thread in the Turbo/Supercharger forum. Its moved to Drivetrain... Quote Link to comment Share on other sites More sharing options...
Jersey Posted March 31, 2004 Author Share Posted March 31, 2004 Sorry John, since i'm doing the turbo swap into the 280 and converting it to CV's, i put 2 and 2 together and posted it there. Might as well just end this topic. Bottom line, the spacers are different so use the right ones. Later. Quote Link to comment Share on other sites More sharing options...
Guest Steve-Z Posted March 31, 2004 Share Posted March 31, 2004 I, also, will be very interested in this, since I will be rebuilding my rear struts this summer. Here's how I think the bearings and spacers work, which is very typical for the spidles on lathes and mills: 1) the strut housing is bored from either side for the outer bearing races and there is a distance between the bearings where the outer races seat on. Call this distance "A" 2) the bearing spacer has to be the same as "A", within +/- 0.001 in, or the bearing will be too loose or too tight, at the thread torque needed to keep the assembly together. It looks like the spindle torque is compressing the spacer to obtain the desired bearing preload, which will eliminate any bearing slop and give a reasonable bearing life. I hope this makes sense. Steve Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 31, 2004 Share Posted March 31, 2004 The more I think about it, the more I think that the torque on the nut shouldn't change the preload. These are ball bearings, and the spacer sits on the inner race of the bearing. The spacers do not collapse and are not crush sleeves (pretty thick IIRC), so where is the preload coming from??? This is not like a tapered roller where you can set the cone further into the cup to up the preload. Am I missing something? Overanalyzing? Jon Quote Link to comment Share on other sites More sharing options...
j260z Posted April 1, 2004 Share Posted April 1, 2004 just to muddy the waters further...when i took my stub axles out of my early 260z, i found that i had one 240 and one 280 stub axle. both had the 'B' spacer in them, which according to my plastic calipers are 52.5 mm, but they both came with a 1mm copper spacer also?... i never had a problem with the axles when the car was running previously. i gave the 240 stub axle to my mechanic for a spare and got another 280 unit for the MML cv conversion but i'm sure i could get it back to do some measurements if needed (my current axles are still uninstalled). i also now have a spare set of 280 stubs that i personally pulled out of the struts which came with no copper spacer but do have the 'B' spacer. Quote Link to comment Share on other sites More sharing options...
260DET Posted April 1, 2004 Share Posted April 1, 2004 Steve's explanation seems to make sense, except for the bit about the spacer being compressed. It looks too solid to be compressed by the forces involved IMHO, also, being reuseable it is not a crush type spacer anyway. The proper, ie Nissan spec, ball bearings would be designed to take some preload I think. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 1, 2004 Share Posted April 1, 2004 How do you preload a ball bearing? If you push or pull on the center in relation to the outer race, that would just make it wear really fast, right? No preload on tranny bearings, or any sealed unit bearings used in front hubs that I'm aware of. I can't think of a single ball bearing that gets used as a straight axle wheel bearing that gets any type of preload. I'm not exactly the bearing guru, but I've been around a few and sold a few in the past couple years... just never heard of bearing preload on a ball bearing. Jon Quote Link to comment Share on other sites More sharing options...
260DET Posted April 1, 2004 Share Posted April 1, 2004 The factory procedure as outlined by Johnc involves preload doesn't it? How else is the specified drag arrived at if not through preloading the bearings then? Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted April 1, 2004 Share Posted April 1, 2004 ah haa.... I finally heard of another person discovering what I discovered, two different stub axles in their 260z!! I thought I was going nutts when I found a 240 stub, and a 260 stub in my 260. I have to bring up the fact again that their are three different spline counts/stubs in the early z cars.... Quote Link to comment Share on other sites More sharing options...
johnc Posted April 1, 2004 Share Posted April 1, 2004 I was down at Erik Messley's shop last night and he mentioned that the 240 adn 260 companion flanges come with a gold colored washer and the 280 companion flanges don't. That washer is exactly 1mm in thickness (measured one last night). I guess this adds a little to the mystery. I have to bring up the fact again that their are three different spline counts/stubs in the early z cars.... I only know of the 25 and 27 spline stub axles. What's the third one? Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted April 1, 2004 Share Posted April 1, 2004 I only know of the 25 and 27 spline stub axles. What's the third one? 26 Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 6, 2004 Share Posted May 6, 2004 New development. I just pulled the stubs out of my '71 spare struts tonight. I had a copper washer on the left side with a B spacer. On the right B spacer with no copper washer. So I guess the question is do I procure a washer, or do I use what comes out of the 280 struts, or do I leave it alone and reassemble. Any ideas? Jon Quote Link to comment Share on other sites More sharing options...
Guest LAYTON Posted May 6, 2004 Share Posted May 6, 2004 i am interested also im i have my stubs coming back from ross at mm right know and when i took them off the car (71) one had a extra washer that the other side did not im doing the z31t axel conversion layton.. Quote Link to comment Share on other sites More sharing options...
johnc Posted May 6, 2004 Share Posted May 6, 2004 What's most important is to get the preload correct. The FSM lists the following as the instructions for reassembly: ... 2. Relationship between the rear bearing housing and distance piece is shown in figure RA-24. 2a. Mark A, B or C is stamped on the top of the housing. Select a distance peice (we call it a spacer) having a mark coincided with the mark ont he housing. 2b. When a distance piece is resused, make sure that both end s are not collapsed or deformed. (Sometimes a copper washer is added by a mechanic if the spacer is deformed). 4. Tighten the wheel bearing lock nut and measure the preload and rear axle shaft end play. Adjust as required. 4a. Wheel bearing preload: 4.9 kg cm (3.9 in. lb) Rear axle shaft end play: 0 to 0.15mm (0 to .0057 in.) Wheel bearing locknut torque: 25 to 33kg-m (181 to 239 ft. lb.) Quote Link to comment Share on other sites More sharing options...
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