How to adjust 8-3/4" axle bearing preload?

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'74 Sport

'74 Sport

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Aaron and I just finished putting his Duster's 8-3/4" rearend back together with new everything. This one came from a '69 Charger, so it has the bearing preload adjuster on the passenger side axle.

I need someone to reply who is very well versed in how this adjuster functions - what it does and how it does it. The axles have way too much end play, so I need to know how to go about making the adjustments.

I believe it is also supposed to have a clip of some sort under one of the retainer flange bolts that keeps the adjuster locked down. If so, it is missing and I need to know what one looks like (any pics appreciated).

Thanks,
Jerry
 
You`re supposed to have about .013 end play as set with a dial indicator. To procede without a dial indicator you can jack up the rear end of the car, remove the wheels, tap the left axle with a hammer to seat it, (next on the right side) adjust the end play to zero then back off the adjuster 4 notches and tighten the lock nut. That should yield between .013 and .023 end play. Repeat if necessary.
 
You can probably take some sheet metal and make a tab. Just something with a hole to fit over a stud and a protrusion to fit into one of the notches.
 
Longgone said:
...(next on the right side) adjust the end play to zero then back off the adjuster 4 notches...
Click to expand...

I assume you mean the end play is measured on the adjustable right side?
How does the adjuster do its job? Do I turn it clockwise or counter-clockwise to tighten (remove end play)? What does it have to do with the left side axle end play? What's going on inside the differential?

The adjuster has alternating tabs turned down towards the axle shaft. The other tabs I guess are left upwards to provide a surface to tap with a punch/drift to rotate the adjuster. Turning it counter-clockwise backs the adjuster outward towards the axle flange; clockwise moves it inward towards the axle tube.

Am I wanting to back the adjuster out so that the turned-down tabs to make contact with the nearby machined lip on the axle, or does that not have anything to do with removing end play? Or do I want to move it inward (what that does I'm not sure).

The rearend is off the car sitting on some jack stands. What do I do to check the end play, just pull out on the axle flange with my hands, or do I need pry out on it harder with something?

Hang in there with me, I'll get this thing figured out with a little more help.

Jerry
 
You have to turn the adjuster in or CW, this in turn pushes on the axle/race which pushes against the axle thrust button inside he carrier (hopefully your carrier still has these ) you will know if they are there or not because by turning the adjuster in it will remove any end play or in and out motion of both axles. If every thing works as I stated above what you want to do is remove allend play then back the adjuster out one or two notches. As you will notice these are tappered axle bearings, the adjuster places the race against the tapered rollers, ideally you want as little play as possible without overtightening them. Drive the car 5-10 miles then jack it up to check the end play again, make sure there is very little in and out motion. If you take the time to do it right you will have many miles of trouble free driving. Also you are aware that you need to pack your bearings in grease? They do not lubricate from the rearend fluid. IE: the inner axle seals. I hope this helps you.
 
Great explanation. I understand completely. The machine shop that pressed the bearings on for us also packed the bearings. Fortunately, he knows MOPAR axles and knew about the adjuster - cleaned it up nicely so it spins easily. We also had him press in some right-hand thread lug bolts on the left axle while he was at it.

I think we can handle it from here guys. Thanks for the info.

Jerry
 
SGBARRACUDA said:
Oh I forgot, I have a axle lock tab if you need one.
Click to expand...

Thanks for the offer, but if you could send me a pic of it, I might be able to make something similar that will serve the purpose. I can see that it just needs to keep the adjuster from backing out.
 
'74 Sport said:
Thanks for the offer, but if you could send me a pic of it, I might be able to make something similar that will serve the purpose. I can see that it just needs to keep the adjuster from backing out.
Click to expand...

Here is a picture of one on ebay. The item number is 170320537637
 
That doesn't look too hard to make. I'll give it a try.
Thanks for the link.
 
to check the end play, you basically first hammer the axle in as far as you can on the right (adjuster) side. Hook up your dial indicator so its reading the "in and out" movement of the axle shaft. Then pull the axle toward you lightly and read the measurement. that is your end play. Keep tightening it up after that until you get within spec. once your done, install the lock.
 
Wouldn't you know it?? Haven't had the rearend buttoned up for more than a week and have to pull it apart again....

to install some 3.23s. \\:D/

A buddy of mine wanted me to go in halves with him on a B-body rearend he wanted to buy for a Charger he's building. Made the 1-1/2 hour trip up near Ft. Worth, checked it out, and made a deal with the owner for $350. My buddy keeps the axle assembly and I get the gears and brake stuff - he is installing 11" ones from his stockpile.

As it turned out, we got 3.23s in a 489 open housing for $175. Not too bad I guess, especially since that was exactly what Aaron and I wanted for his Duster anyway. From what little I know about gear sets, they look perfect - no unusual-looking wear patterns, broken teeth, leaking seals, etc. I hope that we can simply drop them in and enjoy the ride. With the help we got from you guys on this thread, it's a walk in the park to swap them out.

By the way, when you get brake hardware "kits" from the auto parts stores, they don't come with EVERYTHING you need to install drum brakes - like all the extra springs, plates, etc. And some of the parts they do have won't work - like the self-adjusting star wheel.

Thanks for the help,
Jerry
 
Check out NAPA. They have a maxi pak which is the hold down and return springs. They also have a separate self adjuster kit which has the star wheel, cable and other self adjuster hardware.
 
loggone has directed you exactly perfect he knows by his reply i agree have done the same.....many times..
 
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