1993 SAS'd pick-up gets a front Spartan and a much needed check-up
(~107 BIG pics loading)
OCT 18 2014

Here's what Mark's 1993 SAS pick-up looks like as I work on his front 3rd at this moment. Nice weather :)



As received from Mark...good plastic tote with zip ties.

Lots of packing paper...Cola is very interested for some reason.

Looks like the Spartan Locker is in that package.

Front 3rd is there.

Bottom of tote has minor damage due to the 3rd's lip punching at the floor. It takes a lot more padding to
protect the tote floor ;)



4 cylinder Spartan and diff on the bench.




Those 4 pins are so much more stout than the other lunch lockers.

The first order of business is the pre-check. Backlash is checked on every tooth and was basically zero. See
the notes at the end of this link to see the recorded values.


The 304 means this is from a Yukon box. This "brand" of gear is ok but I do have my favorites and those are
Nitro and G2.

This wheel adjuster was not as tight as it needed to be.....If I tighten this side then I can increase the
backlash and the carrier bearing pre-load will also firm up much more.

This side would not even turn indicating the threads were likely out of alignment.

It's more obvious to me but the camera does not show it too well that the adjuster is "cock-eyed"....
pushed in more at the top than the bottom.

These 2 cap bolts were not as tight as they should have been...

...so I carefully removed the cap without disturbing the adjuster wheel. It was quite obvious that the
threads were off one.

Wheel threads were just fine....no damage.

A quick look at the carrier bearings shows that they are in perfect shape...looks like maybe the hubs
were never locked in yet.

Placing the wheel into the threads correctly shows that it still turns easily in the groove and no real damage.

Start the threads on the 2 long bolts... line up the bearing cap into the threads...

...it drops down just like it should...

....and a smack with the rubber end of the hammer makes a nice, solid seating sound indicating the threads
are now in harmony with the universe.

Now the bearing caps can be tightened and the wheels will now turn with relative ease.

Backlash is set to about .007"

This adjuster is rotated about 4 notches tighter than before....

...and this adjuster is a "don't know" because everything changed when the threads were re-aligned.

Paint is applied to 3 teeth and I'm using packing paper here to offer some resistance...

...while the ring gear is turned back and forth with a 17mm wrench.

Drive----nice...centered and slightly deep. My preferred condition.

Coast---surprisingly good.

Look at the tail of the comet....centered. Very good. (The right side is the tail)

This fuzzy pic of the 2nd tooth says the same.

And the 3rd tooth shows the comet about in the center from the face to flank direction.

Now to look at the pinion end ... For some unknown reason, the last installer decided to grind/flapper off about
a full 1/8" of pinion and some nut also.



This triple drilled flange will replace the old one.

The nut was not exactly "tight". No Loctite either.



Grey RTV was used on the outside of the seal and it appears to be in good shape. No big dents in it.

Push the pinion out...

It already had a good solid collar on it....a Marlin collar as indicated by the tall neck at the top.

The 10 ring bolts were tight and appeared to have a high strength Loctite on them.

The Aussie Locker is to be removed ....and a Spartan will be put in its place.

But first, to finish up on the pinion end. Remove the seal.

The solid collar had some chatter wear so I used a flat surface and 120 grit to sand it smooth.
I only remove .001" or less.

I checked all the way around the collar with this extra large set of 12" calipers and it was within .001" variance.

I tried the original 2.435" (collar plus shims) and the pinion pre-load was way too tight.....then added in
another .0035" and still too tight,...added another .002 and still kind tight....added .001" and perfect
at 5 in/lb pre-load. I can tweak the 5 into 10 just by tightening the nut a little tighter. That was
.0065" that was added to the collar.....that means the collar was not installed properly....means it
was effectively rattling around inside there.

Last chance to smother the bearings in gear oil.

The old flange was pretty rough over-all.

The seal surface did have a groove.

Glad that Mark wanted this new triple drilled flange.

Grease on the garter spring and grey rtv inside the bore.

This homemade seal installer works great. Made from an old race and an old flange.

A quick inspection inside to make sure the garter spring did not pop loose. All is good.

No anti-seize on this one...red loctite on those extra clean threads.

Ran it down hard with the electric impact and have about 7 or 8 in/lb preload.

I can get a little more rotation with the 150 ft/lb torq wrench and the double that it is attached to.

10 inch/pounds. Good.

Gonna be tough to ding that nut because of the limited surface left. The red loctite is more than sufficient
but the ding will still happen.

Ding!! Jeez....I needed a more tempered punch it looks like.

Surfaces checked with a big file and checked aok. Hmmm, too much flash in this pic.

A quick check of ring gear run-out shows less than .001 deviation. Very good. Definitely too much flash.

Now onto the Spartan install.

These Aussie springs come out fairly easy with the right slotted screwdriver.


But first, it's a good idea to drive out the steel dowel that holds the cross-pin in place.

The cross-pin came out and was a snug fit. Sometimes, these holes get wallowed out and egg shaped but
this one was as good as new.

Remove the remaining 3 springs.

Remove the drive couplers.

The Aussie is going back to Mark...less the steel dowel that does not belong in this pile.

Here is the Spartan ready to go in.

Sidegear couplers go in first....with NO thrust washer plates.

Loading the pins in place.

Push the pin down and insert the steel wire.


This is a pre-check that should be done and that is to measure the clearance between the crosspin and spacers.
Needs to fall in the range of .006" to .020".

.013" would not fit and .012 fit snug in all 4 places.....unusually consistent.

Drop the one coupler in place....

...and then the other. But, don't do as I just did and have the washer on the right side in backwards :)

It was easy to hold both couplers in place while pulling the wires out with the pliers.

Then slide the couplers til the pins snap into place.

....almost in place....

Bam!!! In place now. :)

The new Spartan cross-pin goes in place.

Tap the dowel in place.

Use a center punch to distort the round hole so the dowel never gets a chance to wiggle out.


Red loctite...

...and 75 ft/lb on all 10 ring gear bolts.

Put the carrier/case in place making SURE the adjuster wheels are in the threads correctly and tighten
the 4 long bolts also to 75 ft/lb

Set backlash while making sure there is good carrier bearing pre-load.

Medium strength blue loctite....

.....10 ft/lb on both lock tabs.

I measured 17 in/lb for the total preload. 17 is the start torq required to turn the pinion AND the ring gear.
Earlier, I measured the pinion bearing pre-load at 10 in/lb....so that means the carrier bearing pre-load
must be the difference between 17 and 10.....that be 7 in/lb for CBPL.

Drive pattern check--- Centered and slight deep.

Coast pattern--- Again, it's centered and slight deep.


Back to NJ