Axle 8 3/4 end play adjustment

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rigrunner

rigrunner

rigrunner
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i've done some searching and can't find exactly how to do this. Can someone explain how the procedure is done? I see what you adjust it with but don't know how to turn it. Is it something you tap around with a hammer and screwdriver or what?


Also...do I need the foam seals where the axles bolt to the backing plate? There was one on the passenger side but nothing on the driver's side. Can I silicone this w/ ATV?
 
Remove the wheels and drums in the rear. Pull the right rear axle OUT as far at it will go. Probably won't be much. Take a rubber hammer and gently tap the left rear axle IN as far as it will go. Now go back to the right side and adjust the end play. I always go down to about .006-.010". At least, that's how I have always done it. I am sure someone will be along to tell me I'm all wrong and argue up a storm.
 
I agree pretty much with StrokerScamp but the clearence is the total amount of play of both axles combined so pushing one in or out makes no difference since they both have to move. There should be a little lock tab finger attached to a stud on the RH axle housing end. Remove that tab temporarily and turn the adjuster nut in or out to achieve .008-.018 end play although anything more than .012 is asking for a leak IMO. You should measure this with a dial indicator against the RH axle shaft for ease of adjustment. Push the axle shaft in all the way, "0" the gauge, then pull the axle shaft out as far as it will go. Read the gauge and adjust as necessary. your method will work... tap the adjuster with a hammer and screwdriver, chisel, punch, etc. if you need to. Sometimes they will turn with your fingers. The foam seal is nice if you can find or make one but not necessary. RTV will work too....it's just to keep dirt and water out of the axle bearing.
 
It makes a difference on a sure grip, Mark. You have the button in the center that the axles will bump against. Doing it like I described will get all of the end play on one side.....at least it works for me.
 
Thanks for all of the help! It is greatly appreciated! I couldn't find this information anywhere!
 
Not to high-jack, but this may be related down the road (no pun intended). Everytime I drove my roadrunner with the 8-3/4" rear, I heard a clunking noise, almost like a wobble, that seemed to originate from the passengers side of the rear end. The sounds occurs whenever I backed out of the throttle or have my foot on the brake (going down hills, around right turns; it quiets down around left turns). When i push on the throttle and the rear end is under load, the "clunking" noise goes away.
I adjusted the end-play as discussed above, but the noise did not go away much, if at all. I set the axle end-play on the passengers side axle to 0.014, using my dial indicator, after pushing in the drivers' side axle.

My question: Is this too much end play? Could there be something else making the noise come from the passenger side of the rear axle?

Thanks all. (Again, sorry if this is considered a high-jack.)
 
I like to go down to around .006".
 
To help 73SwingerBuild I had the same issue on my Demon. My own got worse and started growling....I end up having both axle bearings replaced with the green bearings that don't need adjustment....
 
Bad Demon,
Did that get rid of the wobble/clunking noise? I was considering that upgrade. I know the bearings can be bought for ~$90...
 
When you adjust the axle adjuster your pushing the bearing rollers against the race. As such you want no play. I've adjusted mind this way for ever and haven't had a problem.
 
73SwingerBuild yes it fixed the noise and wobble....Before I took the axle out to replace bearings I could slide the right axle in an out an the adjuster was adjusted properly......
 
............With the adj on the pass side u need to tap on the pass axle to push the drivers axle out to be able to adj the play out...then pull on the pass axle to check the play......remenber righty tighty, lefty loosey .006 is what i set them to.....kim............
 
StrokerScamp said:
It makes a difference on a sure grip, Mark. You have the button in the center that the axles will bump against. Doing it like I described will get all of the end play on one side.....at least it works for me.
Click to expand...
Sure grip or not, the center spacer performs the same function. It floats back and forth depending on axle shaft loads. Pushing the RH axle in all the way also pushes the LH axle shaft out against it's bearing race and vice versa. Too much end play can cause oil to "pump" out through the axle seal and in severe cases, noise, brake problems, and odd bearing wear. Too little clearence can overheat the bearing and cause it to fail.....sometimes by locking up and spinning in the housing and/or on the axle shaft.
 
cudamark said:
Sure grip or not, the center spacer performs the same function. It floats back and forth depending on axle shaft loads. Pushing the RH axle in all the way also pushes the LH axle shaft out against it's bearing race and vice versa. Too much end play can cause oil to "pump" out through the axle seal and in severe cases, noise, brake problems, and odd bearing wear. Too little clearence can overheat the bearing and cause it to fail.....sometimes by locking up and spinning in the housing and/or on the axle shaft.
Click to expand...

Does the open rear have a button spacer? All I've dealt with were sure grips. I know they have them.
 
oldkimmer said:
............With the adj on the pass side u need to tap on the pass axle to push the drivers axle out to be able to adj the play out...then pull on the pass axle to check the play......remenber righty tighty, lefty loosey .006 is what i set them to.....kim............
Click to expand...

Yup. Except I use .010."
 
StrokerScamp said:
Does the open rear have a button spacer? All I've dealt with were sure grips. I know they have them.
Click to expand...
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Yes, but it's a different design, one piece, and a lot bigger. You have to install it when you assemble the spider gears and pin. The pin goes though the middle of the spacer. Here's an example of one.....
 

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I didnt know the spacer was different on an open compared to a SG. I know back in 64 the open used a different thrust block than the SG (+.250) then it was the same for the 741/42/489 series starting in 65 regardless. read this and see if it makes sense:

"There was a difference in thrust blocks prior to 1964 that make center section interchange, as well as axle interchange problematic. The thrust block, or “axle shaft thrust spacer”, it thr block that both left and right axles butt up against inside the center of the differential. Prior to 1964, all open differentials used a thrust block was approximately 1/8″ to 1/4″ thicker than units made after 1964. The Sure Grip thrust block prior to 1964, however, was indentical to all 1964 and later Sure Grips and open differentials. In 1964, the thrust block width was changed to match the Sure Grip thrust block width..." sounds like they are all the same after 64?

I learned that you tighten the adjuster until 0 play, whack the axle in with a mallet. turn the axles a few times, tighten the adjuster again until 0, then back out to just a hint of movement, like a papers width.
 
pishta said:
I didnt know the spacer was different on an open compared to a SG. I know back in 64 the open used a different thrust block than the SG (+.250) then it was the same for the 741/42/489 series starting in 65 regardless. read this and see if it makes sense:

"There was a difference in thrust blocks prior to 1964 that make center section interchange, as well as axle interchange problematic. The thrust block, or “axle shaft thrust spacer”, it thr block that both left and right axles butt up against inside the center of the differential. Prior to 1964, all open differentials used a thrust block was approximately 1/8″ to 1/4″ thicker than units made after 1964. The Sure Grip thrust block prior to 1964, however, was indentical to all 1964 and later Sure Grips and open differentials. In 1964, the thrust block width was changed to match the Sure Grip thrust block width..." sounds like they are all the same after 64?

I learned that you tighten the adjuster until 0 play, whack the axle in with a mallet. turn the axles a few times, tighten the adjuster again until 0, then back out to just a hint of movement, like a papers width.
Click to expand...

That sounds right. BUt you know......what I've always wondered.........those original bearings are tapered roller bearings. In EVERY other application tapered roller bearings have to have preload. I wonder what makes things different in the rear axle?
 
StrokerScamp said:
That sounds right. BUt you know......what I've always wondered.........those original bearings are tapered roller bearings. In EVERY other application tapered roller bearings have to have preload. I wonder what makes things different in the rear axle?
Click to expand...
It's probably the length of the axle it's pressed on. When you heat something that long, it's bound to grow a bunch. Oh, and I don't preload the front bearings either. Just turn the nut finger tight and put the cotter pin in. I got 250K on my last trucks front bearings and the one I drive now has 152K and still has the originals in it.
 
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