Over the last 30 years, I don't know how many times I've had axles in and out of an 8.75 - probably close to a hundred as I've mixed and matched gears, brakes, or complete axles under A's, B's, and C's. I really don't remember having any real trouble, so I hope I'm just overlooking something simple and stupid.

I'm getting my Sport Fury ready for the road, and the axle & rear wheel bearings are really all that's left to freshen up. I've got everything back together, but when I install the axles, both sides stop with a "clunk" with about 3/8" to 1/2" space between the bearing retainer flange and the brake drum backing plate. The studs on the ends of the axle tubes just barely poke through the bearing retainer holes. Enough to start the nuts, but WAY too far out to tempt fate and use them to snug the axles down. In fact, putting a little torque on them makes the bearings get tight.

Both sides have about the same gap.

Both sides are stock 68 C-body axles.

Diff is a 742 SG with 3.23 gears and clutch-type SG unit - thrust block is in place.

I thought that maybe I had gotten the splines out of line when I rebuilt the SG several years ago, but a spare axleshaft I have drops in with just a little wiggle. Splines engage about 1.25" on this SG, another untouched SG, and a couple of virgin open diffs... so I'm *pretty sure* that the diff isn't the problem.

So, what the heck am I doing wrong? I'd really like to get this old girl buttoned up this weekend so I can get her on the road for the first time in 9 years.

Thanks in advance for setting me straight,

Clair

The splines in the sure grip MUST have gotten out of line some how.

Are those the same axels that came out of that housing? I would some how check the depth from the flange to the block in the center and compare that to the axel, also does that housing have the internal axel seal and is it driven in deep enough so not to hit the bearing retaining ring? if all checks out then it has to be a mis alignment with the sure grip splines.

The wheel bearing lock ring can contact the inner axle seal if the seal is not driven into the housing far enough.

Thanks, guys,

The splines in the diffs are - or appear in every way to be - in line. The extra axle (original to the car) drops in equally to each diff I checked. In each case, the axle slides in about 1.25".

The test axle is the one with left-hand thread lugs, I have another 68 Fury axle assembly that I swapped lugs on to RH thread. I compared both and they seemed to be the same.

The axle bearings are unchanged, they all felt good and cleaned up well.

The inner axle seals WERE changed, and both seemed to install up to the point that they seemed to bottom out. I used a proper seal driver, and they went in nice and straight.

I'll see what I can do to verify that the bearing locks are not contacting the seals.

Thanks for the leads, guys, keep 'em coming!

Clair

You said the "thrust block" is in place with the SG, but could both of the thrust buttons? fallen out/dislodged and be blocking the axles from seating?

For reference https://board.moparts.org/ubbthreads/showflat.php?Number=5161729

are the spiders lined up? some have 2 piece spiders on one side,and I have had them not line uo,and must be assembled w/ a axle to make sure these are lined up.this might be the issue...the pros might weigh in....mike

The thrust buttons are in place on both SG's - in the "good" one, the one I went through years ago, I replaced the buttons with the Mancini / Mopar kit back in ~1990-ish. In the "mystery" one, the original roll-pin appears to be holding the buttons in place, but they're both present and accounted for.

Checking again tonight, the axle dropped in to both diffs. Flipping each diff over and checking one side right after the other, the second was always a little snug. A little wiggle on the axle and it would go, but I'm wondering if there just isn't any wiggle left when putting it in the axle housing?

Hmmmm.......

Clair

Once you get both axles installed and tighten correctly try using two straight edges off of the axle flanges and measure out from the axles flanges straight forward and then on the back side also, I use 16 inches form center each way, to see if the axle housing is bent If it is bent it will be either wider on the front or rear and than the other way, same thing up and down also Let us know what you find, my Duster rear end was narrowed and the axles would not slide in easy after the narrowing. It ended up bending the pasenger side axle housing (after several years fo racing the car)bad enough to rip the ladder bar mounts off of the housing

I am having the same problem with my 742 also just on the passenger side ...Your splines are probaly not aligned with each other.Good luck because I am having a heck of a time getting them to align.

OT, How did you take that pic?

iPhone... holding a drop light in my left hand, zoom in a little with the right hand, move the light around as needed to get the edges to show up. For REALLY small stuff (like the watch parts I tinker on in my "spare" time), I put a jeweler's loupe in front of the camera lens and it works great. Even a cheapo $10 loupe from Harbor Freight works like gangbusters.

Now if I can get the carb on my leaf blower rebuilt, I might have some time to tinker on the diffs again...

Clair

Every now and then I have a tense moment when one won't go in, and I KNOW it's the same parts that came out...last one I got a wood block and a 5 lb 'persuader' and used a few judicious taps on the axle center register.The outer bearing shells were a bit reluctant was what ended up to be my problem.

And the winner is:

DR DIFF!!

It was almost immediately obvious that the bearing lock ring had made contact with the seal. In this pic, you can see the ring scraped in the coating on the seal:

68_Fury_Axle_Seals-01 by clair_davis, on Flickr

Here's how deep the seal is SUPPOSED to be installed:

68_Fury_Axle_Seals-03 by clair_davis, on Flickr

I think my "proper" seal driver was just as big, or perhaps slightly larger than the seal, so when I heard it bottom out, it was the seal DRIVER that had bottomed out, not the seal itself. Fooey. About 10 seconds after I saw the ring on the seal, it occurred to me that I did NOT bring my seal driver kit with me (the car is 70 miles from my home, so I have to pack everything I need for the job). Fooey isn't exactly the word I used here. Fortunately, I had plenty of brake parts cleaner cans sitting around, and those are nearly perfect drivers based on my cheap ba$tard experiences in the past. These seals were TIGHT, and this is what the thin can looked like after the operation:

68_Fury_Axle_Seals-02 by clair_davis, on Flickr

After the seals were fixed, a quick test of the axle showed that it dropped right in and the flanges mated up properly... next to test with the diff in place, too. With the diff held in loosely - just enough wiggle to help if I needed it - the axles were next. Absolutely NO drama this time. Clunk. Clunk. Axle shafts in. Tighten the diff nuts, tighten the axle flange nuts, set the end play, lock it down, fill with gear oil and SG additive, bolt up the driveshaft, done.

68_Fury_Axle_Seals-04 by clair_davis, on Flickr

And then it was time to round up the kids and head home... Driving will have to wait until next time I visit my folks, probalby over Thanksgiving.

Thanks again for all the help!

Clair

you have obviously never seen an aerosol can explode.

Other than intentionally.... No, I'm probably fortunate about that. I'm also kind of anal about ventilating my used spray cans before disposal, so this one had been punctured several weeks ago. Pretty sure there was nothing in there to combust, but it's a good point you make.

Clair