Rear Wheel Bearing Related

[Zed Head]

Anybody ever wonder how the crimps on the locknuts affect the torque reading?  Just something to keep you awake at night...

[grannyknot]

1 hour ago, Zed Head said:

Anybody ever wonder how the crimps on the locknuts affect the torque reading?  Just something to keep you awake at night...

Wouldn't they just cause a little more drag so it would require more effort to get it up to torque but the torque would be the same?

[Zed Head]

I was kind of joking.  If you had a beam type wrench you'd see the deflection when the crimps hit and could just add it on.  It's probably about 10 ft-lbs added to the 200+ spec.

[AK260]

I’m with zed head on this one!! I literally found myself hanging off a massive 300lbft torque wrench to get close to the spec’s max. OK, I do only weigh 73kg (160lb) but it’s all pure muscle and teeth!

 

The range in the spec is so wide between the years that I wouldn’t fret a 10lb here and there difference.

 

When you get close to the required min torque (say over 190lbft on mine) there is so little movement required to jump up 10lbft that I doubt it would really matter! Unlike you, I went peened nut as it was in the end a fire and forget situation. It’s one of those that you can’t really inspect that easily after a few miles and you never want to go loose. Strangely, by contrast the front bearings are practically finger tight at the correct torque and pre-load settings!

 

 

 

[adivin]

Just to add another wrinkle, I have the "noise-insulating" copper washer which calls for a reduced torque spec.  94 - 123 ft-lb.

 

[AK260]

Ah yes, forgot you had an earlier car.

I know others have had a lot of success with the 280zx nuts but I personally feel more comfortable knowing what a female dog that peening is to get off and therefore how it’s never gonna let go once bent into the flat. Also what is the torque spec for the 280zx v the 90lbft?

What is the thinking on the nut being designed for use with higher torque but being torqued to half that on an earlier car?

I don’t wish to complicate your life but this is one of those safety things that keeps me awake at night! Except of course for children coming in to tell me they had a successful moment in the loo, or their teddy fell off etc! Maybe when they are teenagers I get to wake them up in the middle of the night and tell them my ear plug fell off.

[adivin]

7 minutes ago, AK260 said:

Ah yes, forgot you had an earlier car.

I know others have had a lot of success with the 280zx nuts but I personally feel more comfortable knowing what a female dog that peening is to get off and therefore how it’s never gonna let go once bent into the flat. Also what is the torque spec for the 280zx v the 90lbft?

What is the thinking on the nut being designed for use with higher torque but being torqued to half that on an earlier car?

I don’t wish to complicate your life but this is one of those safety things that keeps me awake at night! Except of course for children coming in to tell me they had a successful moment in the loo, or their teddy fell off etc! Maybe when they are teenagers I get to wake them up in the middle of the night and tell them my ear plug fell off.

It is my understanding that the torque spec is the same with the 280zx nut.  Someone, perhaps the Captain, can confirm.

The difference is not that it's an earlier car, but that it is an earlier car with the copper washer installed that goes between the bearing and companion flange that makes the difference in torque spec.  I suspect the thickness of the washer changes things.  

[Zed Head]

I think the torque spec is so wide because the goal is to get the end play and preload in range by adjusting the torque.  They have set the specs. so that you have to fiddle with it until all three are in the ranges shown.

The reality is that nobody measures end play or preload so you might as well just pick a number in the middle of the range.  It will have the best odds of meeting all three specs., based on how spec. ranges are typically set.

Here's the 280ZX description.  I don't know when they added the part about replacing the distance piece, it's not there (I think) in the 280Z FSM.  That part just makes it even more confusing since they don't say what you're trying to accomplish by replacing it.  I think it's one of the worst procedures I've seen in a service manual.  It's from the 1982 FSM.  Torque...check..no good...replace... endless loop possible.

Edit - actually I see that they said preload OR end play.  Weird that one can be out of spec., apparently, if the other one is in spec.

Edited September 30, 2020 by Zed Head

[Zed Head]

1976.  Just "Readjust as required", but still specifying three ranges to hit, all at the same time.

[AK260]

Interesting. When I did mine, both sides were tested for preload and once I got past my issue with the grease seal, I found that the difference between 230 and 190lbft was minimal (but the force required on the torque wrench to go from one to the other was significant!), see below...

 

 

 

Why I thought.

 

 

Then I looked closer at the diagram and in effect the bearing centre races, hub centre spacer, axle shaft, washer and nut are becoming as one. The only thing the torque is affecting is compression / deflection in that centre spacer (“distance piece”) - which is a beast of a bit of metal.

 

I can imagine a copper washer being softer would “crush” more if tightened to those later specs.

 

As you say though, I didn’t bother with end play measurements.

 

 

 

 

 

 

 

[adivin]

Ak260, what was your grease seal issue?

[Zed Head]

54 minutes ago, adivin said:

Ak260, what was your grease seal issue?

Is this "meta"?  Still trying to get a good grasp on that word..  

 

 

Edited September 30, 2020 by Zed Head