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Should I be worried about my axles/halfshafts?


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Ok so I've got some basic tire on my can now and I'm like some input on what I can expect out of the rear components in my 260 with what I want to throw at it.

 

I have an early '74 260z with an open r200 (I THINK 3.90) diff...i believe the halfshafts/axles are out of a 280...but may be the stock ones from my car. I'm running a ~500hp(crank) 383 and a built/kitted etc TH350(shifts pretty damn hard). So far everything has held up well under pretty aggressive driving..I just put brand new street tires on it and can finally start to grab OK in 1st gear. My driveline was also custom made and should be one of the stronger parts in my drivetrain...leaving the axles as the weakest link i think.

 

My question is this...how likely am I to hurt any of the axle parts with these street tires and my automatic? Both on the street and at the track (assuming i hook pretty well)? Have any of you broken them in the middle of a pass? (not off the line). I also would like to put maybe a 150 shot on the motor, as the motor was running on nitrous regularly in the previous car. I'd be looking to squeeze probably in 2nd gear...and I'm wondering if even that might be enough to shock one of those parts enough. Any input is greatly appreciated. Thanks!

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Yes, you should be worried about your half-shafts.  They were not meant for the kind of torque and shock load that a V8 engine produces from a stop.  I don't see how you can grab ok in first on street tires if you are pushing 442 rwhp (per your sig).  I have an LS1 in my car and with 245's that have a  340 treadware I can light them up on command from a stop (as in leave smoke at a stop light without revving up to the stock stall).

 

I have a 3.70 LSD in my car as well and after two scary incidences in the past 2 months, after driving the car for 2 years, I finally made the switch to CV's so that I can put stickier rubber under me.  I never put anything stickier (like drag radials) on my car because the half-shafts were the weak link.

Edited by ktm
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You'll be OK until they fail.  Might want to put some sort of safety loop around them, they tend to tear up control arms and brake lines.  They can fail at any time.  After I broke a driveshaft, I marked the new yoke with some parallel lines so that I could see it twisting, hopefully prior to the point of failure.  After one night at the track, when I inspected it, it had twisted a probably 15 degrees (I replaced it before failure), so who is to say whether if that last little twist, that proves to be too much, would be at a stand still?  I have a buddy who broke a stock axle on a 2-3 shift without NO2, but it was with a manual trans.  Its not a matter of IF, its a matter of WHEN.  My racing buddy had a cross shaft get cocked inside his one-legged R200, and when it did, it locked that wheel long enough to break an axle at the outside yoke.  He was half way down the track when it broke.  It didn't do much damage-we had another diff and axle on it in a couple nights and were back at the track the following weekend.  Don't do burn-outs, and if you feel wheel hop, get out of it.  I run CV axles; even so, this year I plan to install axle safety loops and build up a spare set of axles to keep in my truck when I go to the track.

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Something has to give, i prefer the halfshaft to go before the differential .

 

I don't.  An open diff is cheap.  A half-shaft spinning wildly around knocking out brake lines, fuel lines, etc. is a hazard not only to him but others around him.

 

I used my tires as a safety valve.  They would spin before putting any serious shock load on the half-shafts.  The problem there, though, is that they'd spin when I really did not want them to which led to a few embarrassing situations..

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I don't.  An open diff is cheap.  A half-shaft spinning wildly around knocking out brake lines, fuel lines, etc. is a hazard not only to him but others around him.

 

I used my tires as a safety valve.  They would spin before putting any serious shock load on the half-shafts.  The problem there, though, is that they'd spin when I really did not want them to which led to a few embarrassing situations..

I'd be inclined to agree...This was why i wasn't worried so much up to this point...as I would shred the tires (both) loose with my open rear end whenever i hit about half throttle in 1st or 2nd gear. But since I've gotten these new tires...I'm actually able to lay into it pretty good about halfway through first if I roll into it steady. My main concern now is the shifts. My tranny has a custom shift kit in it that is VERY aggressive..and my main concern is shifting into 2nd on the juice and disintegrating a an entire axle assembly. I would kind of prefer to blow the diff up...seeing as the rest of the car would be less destroyed.

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Would I be better or worse off welding my diff? I know it would distribute power to 2 axles instead of one...but i can also see how it might add to the stress they see under normal driving.

 

 

I would think it would compound the problem. The open diff takes torque away from the wheel with more traction, therefor putting less stress on the axle. To make the situation worse, when taking tight turns, you're then putting a lot of torque into axles with no differential action. As much as it takes until a tire breaks traction and starts skipping.

Edited by m1ghtymaxXx
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  • 3 months later...

I recently broke a half shaft on my 78 280z. Stock l28et with a tune. 10lbs of boost. 211hp and 240tq. It broke the day after I had it tuned. It banged up my brake line a bit but it's an easy switch. I don't understand why some people are saying that a broken diff is better than a halfshaft.....what am I missing?

 

My u-joint snapped and the ear in the half shaft was twisted. Could this be a u-joint failure? It was a greaseable u-joint with the hollow center. Would I be better off purchasing solid ones? I'm not making nearly as much power as many others and I'm trying to understand why it snapped.

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What were you doing when it broke? Have you checked the diff to make sure it is fine? Sometimes an axle breaks because the spider gears in the diff lock and that effectively tries to stop that wheel. So, sometimes an axle failure is because of a diff failure. It doesn't take a lot of power to make the spider gears lock, rather it is a wear problem of the tiny cross shaft. Worn cross shaft lets spiders lock, which locks rearend which breaks axle. Look for pieces of your spider gears inside the diff.

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We rarely break diffs with a CLSD because the CLSD doesn't have a cross shaft. So when something breaks its the axle. The folks who say it is better to break a diff say that because when you break the diff most of the broken parts stay inside and unless you somehow break the case, all the oil stays inside. If you break an axle at speed, the axle flails around and trashes brake lines, fuel lines, whatever. And you wet the track down with oil, it shuts the track down for a couple hours and about 200 hardworking car guys that used to respect you now hate your guts cause you shut the track down.

Edited by RebekahsZ
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Hey Rebekah,
I was rolling in first and then hit the throttle and went to second and it snapped the u joint. I was wondering if it could have been a weak u joint. I'm not sure. Some people say it's better to stick with solid u joints. As of now I'm looking for a replacement half shaft. My plans are to get a clsd r200 and switch to cv axles. I would like to switch to cv first and then get the clsd. I've seen some peoples threads about the conversion but didn't see anything about cost. My car is also lowered but not extreme. I wonder if I had a binding issue. I'm at a loss. Not sure where to go from here.

Edited by rome03
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It was probably a worn u-joint in that situation. When had you last replaced them? Likely never, if you are like me. With that power level I would just replace them all and get back driving. Any u-joint should do. The solid ones are getting hard to find. Just slap anything in there. I'm site your axle didnt bind, never heard of a stock axle binding. Go to the salvage yard and get a couple spares and rebuild them. It will be like taking an umbrella to a ball game. Never rains when you are prepared.

Edited by RebekahsZ
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I had actually replaced all four of them three months ago. They were new. I did about a total of four launches from zero within that time frame. Mostly I would go hard on the throttle from a roll. I just picked one up today that I'm going to slap on so I can get back on the road. 

 

My car sits pretty low, the lower control arm is pretty much straight, it doesn't angle down. What do you mean by a stock axle not binding? You don't think it can bottom out if the car is low enough? I started to think that it could have been that because the u-joint didn't just snap off cleanly. The eyelet of the half shaft was also twisted. I though that since the car is low maybe it bottomed out......

 

Do you think I should shorten them just to be sure? Should I convert to cv axles instead? I know that I can run the 280zx or the 300 zx cv's but which one would require less modifications. I saw that they have adapters that bolt up to the stock 4 bolt flange on both sides and them bolt up to the 6 bolt cv axle.

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I had actually replaced all four of them three months ago. They were new.

 

I started to think that it could have been that because the u-joint didn't just snap off cleanly. The eyelet of the half shaft was also twisted. I though that since the car is low maybe it bottomed out......

 

Do you think I should shorten them just to be sure? Should I convert to cv axles instead? I know that I can run the 280zx or the 300 zx cv's but which one would require less modifications. I saw that they have adapters that bolt up to the stock 4 bolt flange on both sides and them bolt up to the 6 bolt cv axle.

The 280Z's were designed for half-shafts with R200's.  It would be odd if they were binding and even if they did I think it just pushes the strut outward, and/or causes the suspension to bind.

 

What brand of u-joint did you break?  Just for the record.

 

Might be cheaper/easier to find half-shafts like RZ suggested, that have the precision-fitted factory u-joints. Nissan put a lot of effort in to making the u-joint fit perfectly.

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Sorry, man, I'm out of ideas. Seems like you did everything right. I'd put it back together and try it again. At least you will get another data point. I dealing with the same think, kind of. I just broke a CV. If I look at the situation, it would seem that it was caused from going from 26x9 to 28x10.5. Was it the extra tire diameter or the extra width? Or did a crack start last year and it took a few more runs to break it completely? I don't know how to determine that.

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NewZed,

Yea I just picked up a halfshaft today. Im going to put it on and hope it doesn't happen again. If it does i'll start looking at alternatives.

 

Rz,

I saw the pics you posted, it just sheared off. I guess time will tell for the both of us ha. Im running 225's on 15 x 10's. I thought that all of that extra grip could be adding a lot of additional stress. Who knows. which clsd are you running?

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