rear end grinding

[androopa]

1991 legacy - AWD-
how do i know if it is wheel bearings or CV joints which need to be replaced in the rear?

when i am driving i have a low pitched grinding which is constant at all speeds. it is hard to tell which side it is coming from but when i make left hand turns it does have the popping sound from the rear passenger side--the boots look good and clean on both half shafts.
when i turn the wheels by hand it sounds like i may have some noise coming from the drivers side rear wheel...maybe a bearing? i just dont know how to tell the diff between a bad bearing or CV joint--and i would like to make sure due to the cost of each part.
i already changed the brakes and rotors-and removed them when turning the rear tires just to make sure they were not making the noise.
i had a vibration also in the rear but i changed the u-joints(drive line,) and that problem is fixed and the rear diff fluid is good clean and free of shavings

[Legacy777]

Bearings tend to give you a growl/howling sound

If I had to guess, I'd probably say bearings, but that'd just be a guess. Have you tried jacking up the rear and shaking the wheel to see if there's any play?

[androopa]

not so much movement in the tire or hub assy. --so i'm going after the bearings and almost have it all apart-
now when i get that axel out how can i tell if the CV joint needs to be replaced also...what are some basic signs that i should be looking for to indicate needing to be replaced?

[beatersubi]

If its cracked or ripped anywhere or if the rubber is showing signs of being dried out.
Those bearing will need to be pressed out and into the hubs.

[kimokalihi]

I had 3 wheel bearings out in my 90 NA L wagon. It was a lower howling noise. The previous owner told me it was the rear diff but he was wrong, the rear diff was in great shape. The car has 275 thousand miles on it but the rear diff was in excellent shape.

I replaced the wheel bearings and the noise was gone. Instead of replacing the bearings themselves which requires a press, I just hit up the junkyard and for $25 a piece I replaced the entire hub assemblies. I would recommend that. Only problem is if you get another bad one from the junkyard you have to take it back off and exchange it which did happen with one of them but it was still worth the money I saved.

The dealership wanted $1,400 to replace all 4 wheel bearings! Les Schwab wanted $700! I did it for $75. Make sure you bring one of those forks and a sledgehammer to remove the lower control arm because those bolts that pivot are ALWAYS rusted in real good. I didn't have a fork so I had to sit there for about 15 minutes pounding the living shit ouf ot the control arm until it broke loose. That control arm was not in good shape after that!

[androopa]

KIMOKALIHI--thanks for what you said
i am having trouble with that control arm bolt but i got it spinnin so i know with a few whacks it'll come on out

so my C/V boots are dry lookin, but not torn or greasy--is there anything to be lookin at for wear and tear once i get them removed? which will be today.
i know that they are old--i'm guessing that they have over 100k on em. what is the general milage a C/V joint usually gets befor needing to be replaced/

[kimokalihi]

Oh I forgot, a great trick I figured out while beating the shit out of the control arm at the junkyard was to find something really solid like a big rock or solid metal part and put it under the hub assembly so that bolt is resting on it. That way when you beat on the control arm the suspension won't absorb the blow. That was really holding me back until I did that. I couldn't find something the right height though so I located a jack in the back of the car and jacked up the control arm and put a large object under there and let the jack down. After that it was nice a snug on there and it only took a few good wacks with that small sledge I had.