Restoration of BringaTrailer 240z - HLS30-35883

[Namerow]

13 hours ago, inline6 said:

Free length is about .890" and it is only composed of just under 4 coils.

Hard to see how the Factory counted 5.5 turns for the spring, as it's shown in the FSM diagram.  I agree with your count:  just under 4 turns (and your long spring matches well with the one on the FSM diagram).

Your short spring looks like it's only 3 turns.  However, the wire gauge looks like it may be thicker.  Did you measure it?

Edited October 24, 2023 by Namerow

[inline6]

Yes, the shorter spring has a wire thickness of .116".  It may be possible that at the same installed height inside the rack, each spring is close to the same pressure/load.

[inline6]

Tonight, I swapped the short spring in my rack out for the longer one that matches the factory manual.  I also put one thin shim between the bronze bushing and the spring, and then, the thick and thin shims, in that order, and then the retainer. 

The factory manual specifies that you tighten the retainer screw "until it stops".  What makes it stop is that it bottoms out on the retainer (bronze piece).  Then, you back off the retainer screw 20-25 degrees.  I shifted the rack fully to one side, and then set the retainer screw per the factory manual.  Doing this, I feel, sets the spec for the rack in a "low wear" zone.  I think this would be closest to what the rack was like when it was new.  My rack doesn't have much wear that I could see, but when you are talking about "retainer floating play" (clearance between the retainer screw and the retainer) of .0035", I think it is best to set the distance the way I did for a used rack.  

I also replaced the coolant in the rear struts with 10W30 oil.  And I started to install one of the rear wheel hub/axles. 

    

 

From the factory, axles were not painted.  They were installed in a freshly machined state.  I decided to glass bead mine and then put a light clear coat on them to provide some rust resistance.  

I clear coated only one of the axles several weeks ago after both were glass bead blasted.  With that time sitting in my garage, the non-clear coated one started rusting noticeably - the clear coated one has studs installed:

    

 

New parts and the hardware for the brake shoe backing plates:

    

 

Starting axle installation "B" on spacer and on strut housing:

    

 

I believe this washer I am holding is the phosphorous copper washer mentioned in the TSB below.  It is pretty clear from the transfer of material to the axle flange where it was located.

 

Note that the torque setting on the rear axle bearing lock nut is far lower - only 93 to 124 ft-lbs vs. 181-239 for VINs HLS30-19584 and prior.

 

I am at the point of the axle installation where I need to add more grease.  I have filled the inside of the outer rear bearing, both sides of the inner bearing, and the inner oil seal.  Look right?  Thoughts on how much grease to put in the axle housing?  Do I fill the whole strut housing cavity, attempting to eliminate any air pockets?  

    

 

[Captain Obvious]

9 hours ago, inline6 said:

 Do I fill the whole strut housing cavity, attempting to eliminate any air pockets?  

I thought I was really smart when I did my wheel bearings and I came up with this elaborate plan to fill the entire housing cavity with grease. Even involved injecting grease with a large syringe:

Well after I completely packed the entire cavity with grease and put the whole assembly together, it was really hard to spin the stub axle. Way way too stiff.

I had to take it apart again and pull some (most?) of the grease back out. So short story? I would not do that. I would pack the balls of the bearings and put a little extra in there and call it a day. I would not fill up the whole thing. Sounds like a good idea, but it's not.

[emccallum]

It probably would get even worse when it heats up. I too didn't pack much in it. I would think its mostly for corrosion control. 

[Namerow]

On 10/24/2023 at 12:48 PM, inline6 said:

Yes, the shorter spring has a wire thickness of .116".  It may be possible that at the same installed height inside the rack, each spring is close to the same pressure/load.

Interesting.  Assuming the same material and coil diameter, the spring constant for a regular coil spring varies as the fourth power of the wire thickness.  At 0.116" vs. 0.102", the shorter of your two springs should be 67% stiffer (lb/in).   

The fully-compressed height of the short spring looks like it would be 3.5 x 0.116" = 0.41".  The free height looks to be ~ 75% that of the taller spring, so 0.75 x 1.035" = 0.78".   Full compression distance would therefore be 0.78" minus 0.41" = 0.37", so the preload force exerted at full spring compression would be 0.37 x 1.67K = 0.62K, where K is the spring constant of the longer spring. 

Using the same approach, the longer spring looks like it would have a fully-compressed height of 4.5 x 0.102" = 0.46".  Full compression distance would therefore be 1.035" minus 0.46" = 0.58", so the preload force exerted at full spring compression would be 0.58K.

So (if I got my math right)... At full compression, the shorter spring will be exerting about 0.62 / 0.58 = 7% more preload force, compared with the longer spring.  That's pretty close.  In fact, they're probably the same.  The shorter spring will be more sensitive to turning the adjustment screw in and out, and it will get from max. preload to zero preload a lot faster...  but I can't see that being an advantage. So, why?

[inline6]

Thanks for the math.  

I suspected that at the installed spec, they may have very similar installed loads.  I am guessing a production run change occurred.  As to why, perhaps the shorter spring with thicker wire is more durable - less likely to fatigue?

 

Edited October 26, 2023 by inline6

[inline6]

14 hours ago, Captain Obvious said:

I thought I was really smart when I did my wheel bearings and I came up with this elaborate plan to fill the entire housing cavity with grease. Even involved injecting grease with a large syringe:

Well after I completely packed the entire cavity with grease and put the whole assembly together, it was really hard to spin the stub axle. Way way too stiff.

I had to take it apart again and pull some (most?) of the grease back out. So short story? I would not do that. I would pack the balls of the bearings and put a little extra in there and call it a day. I would not fill up the whole thing. Sounds like a good idea, but it's not.

Thanks for this info.  I was thinking to jam pack the thing.  However, I saw the factory manual picture which indicated only a few areas to grease.  I am having a hard time believing that, comparatively, a small amount of grease packed onto the bearing is sufficient for 4 or more trips around the globe, mileage-wise (25,000 miles around at the equator).  

So basically, the amount of grease I already have on the bearings and the seal... plus a little in the cavity to keep it from surface rusting is the way to go?

 

Edited October 26, 2023 by inline6

[Namerow]

8 hours ago, inline6 said:

However, I saw the factory manual picture which indicated only a few areas to grease. 

You'll see the same thing in the FSM for the front wheels...

I wonder if this has to do with the centrifugal force that acts on the grease when the wheels are turning at speed?  There are two grease 'reservoirs' here: one formed by the pocket in the center of the wheel casting, the other along the wall of the dust cap.  In each case, the grease will try to flow out to a region with a larger diameter.  This would have the pocket inside the wheel casting feeding the inboard bearing and the grease in the dust cap (notice the slightly conical shape?) feeding the outboard bearing. 

Or... maybe it's not so much a question of having the grease actually flow as it is one of creating some pressure on the grease in the bearing cavities.

If it's not one or the other, then the idea of putting grease into these two reservoirs seems kind of mindless.  It might also explain why it's not a good idea to over-pack the wheel and the dustcap with grease (the pressure at speed might overwhelm the inboard grease seal).

Just my theory.  Probably only a chassis or lubrication engineer would know for sure.

[Captain Obvious]

10 hours ago, inline6 said:

So basically, the amount of grease I already have on the bearings and the seal... plus a little in the cavity to keep it from surface rusting is the way to go?
 

That's my read. I'm not sure I understand the concept either, but it seems to work. In ancient times, wheel bearing grease had strands of fabric or fiberglass included in the mix. Made it stringy with the intention of those strands would get caught up in the balls and pull grease into the bearings as they spun. As grease was expelled from the bearings, it would be pulled back in with the tangle of strands. However, newer wheel bearing greases that I've bought (newer being in the last ten years?) do not seem to have those strands included. Seems to be a smooth paste.

Couple theories, ideas, possibilities?

Maybe the grease melts into a liquid during use (when hot) and flows in and out of the bearing balls with ease? 
Maybe the grease just stays put where you originally smeared it?

I don't really think either of those last two really happen, but just tossing out ideas.

[grannyknot]

When you get up to the 280z, both the inner and outer wheel bearings are sealed inside and out, a bit of grease between the seal and bearing is all that is needed.

[inline6]

I was able to find the time to swing by a local Nissan dealer and pickup the throw out bearing collar I ordered last week.  This is the short collar - correct for use with a 240z clutch assembly:

re

 

I got new springs for that collar and the clutch fork as well for good measure, and I ordered a speedometer drive gear assembly.  The one I ordered has a red gear to match the 4.11 diff. gear ratio.

The throw out bearing was the last thing keeping me from installing the engine and transmission in the car... so, I did that tonight!  

 

It was a bit tricky to maneuver everything.  Engine and transmission are sitting on car dollies, with wood stacked to get sufficient height and stability for mating up with the car body coming down from above using my lift.  Having the assembly on wheels was important for alignment with the car body.  I shot some video, but it sucks.  Those Youtube people have talent.  I will explore editing them and see if I can salvage anything worth viewing.

 

Front crossmember hardware:
    

Transmission to engine and transmission mount hardware - one of the transmission to engine bolts is extra.  It only requires 4:

    

 

    

 

    

 

The engine is in!

 

 

Edited October 27, 2023 by inline6