Is there a way to check if axle bearings are still good or need to be replaced? I have the axles out of the car. Do bad bearings make noise or vibrations when driving. Since I have them out now would be the time to replace if their bad. I have been chasing a vibration. thanks.

good question. Also whats the best way to set the end play? is there a spec?

The bearing will "roar" when they go bad. We had one in a 73 Dodge that got water in it and basically rusted out. The bearing should spin freely and cleanly as a front wheel bearing. They are lubed with grease and not the gear lube in the rear, so both the inner and outer seals must be good to keep the bearing sealed. On an 8-3/4 the spec I have for 68 model year is 0.013"-0.023" end play which is adjusted by the spanner on the passenger side of the rear and locked by a clip mounted to one of the backing plate studs.

If you can't remember changing them, just change them. I had a scare on a trip to Los Angeles. Started to make noise. Got mine from Dr Diff. Front and rear. I got the "green" ones.

Thanks for the responses. Maybe I should just change them, that way Ill know their good. Could anybody give me a quick run down on how to do it. I know I need to use a cut off wheel on something And then get the old bearing pressed off and new green bearing pressed on? Is this correct? Any help would be appreciated. Thanks.

Yes you will need to cut the old ones off. On an 8 3/4 you use side cutters like for a cotter pin to open the outer bearing cage, then cut a notch in the inner race with a grinder to make room to remove the rollers one by one. Then the outer race and bearing cage can come off. Then you use the cutoff wheel to cut down the inner race almost down to the axle. One shot with a hammer and chisel will split it. You also use the chisel to notch the pressed on collar in a few places so it expands and will slip off. Notch it parallel to the length of the axle shaft.
The green bearings don't use the stock end play adjusters.

If you have never done it before you are in for a treat. Multiply the time allocated by 4 and you might be close. It is a real PITA. I actually like using a Dremel with the smaller reinforced cutoff wheels as it gets closer to the "cheek" of the axle when cutting the race and splits easier. It is hell on a Dremel though...

If this is a street car you might want to get some opinions on using the "green" bearings. They aren't meant for cornering so you might be repeating this process. It depends on how much you drive it (I wouldn't use them on a street only car).

Yes it's a street car, 8 3/4" rear. Are the original style bearings still available? Seems like everybody is using the green bearings for replacements. I do know that some have concerns about lateral forces. Can I still get the original style bearing?

I just got mine done with stock bearings a few months ago

The new Timken tapered bearings ARE still available for about $50 each. Knock offs can be had for abouyt $36. These are NorCal prices.

I just cleaned and repacked my old originals a little while back.

the oe tapered ones do get loose in the race. If yours NEED replacement I would get some new tapered Timkens rather than the greens

New adjusters are not available, so that's why new axles have Green bearings installed and are marketed as being better since they don't require adjustment.

Honestly, I have never understood the logic behind the adjuster argument... What's so difficult about adjusting a bearing? Especially on the rear... I mean lets face it, there's only the one!
It's a piece of cake...

In my car it sounded like I was driving over the steel grating of a draw bridge- or rumble strips. Very attention demanding growl.

If in doubt change them out...

What others have said about using the Green bearing on the street they don't like lateral loads very much. The inner and outer seals are or were available last time I looked just be careful and save your retainers.
Has anybody packed their wheel bearings with synthetic grease and do the seals hold up?