Last summer I was driving my car and my buddy was behind me.... he started flashing his lights and motioning for me to pull over....So I do and he tells me " Man your rear drivers side wheel looks like it's going to fall off" ... as I never felt anything at all I said to him " lay off smoking crack bud..." lol... but to be sure I let him drive my car and I followed behind him in his...

Holy crap.. he was right... the drivers side wheel did look like it was wobbling bad...it appeared to go side to side...

So here is what I did to try and diagnose the problem.

1. First thing I checked was all of the wheel lugs... jacked the car up to take the load of the wheel and checked the lugs. Yup all good. I even removed the lugs and made sure the wheel wasn't on wrong... nope all checked out here.

2. Next I jacked up both sides of the rear and put it on axle stands. Started the car and put it in gear so both wheels would spin... sure enough, drivers side looked like it was going back and forth.....the passenger side looked whip straight. Thinking a bent axle I decided to pull the drivers side wheel off again and just look at the rear rotor/caliper assembly moving. Yup, while the axle is spinning you can see the rotor wobbling causing the caliper to "float" back and forth(although less noticeable, this would be expected as it is a smaller "wheel"... So I then pulled off the rotor and caliper and just looked at the flange and axle and there was a very very small wobble (again to be expected as this is a smaller "wheel" again).

3. So I say to myself... ok I have a bent side axle... but I wasn't convinced that the rim wasn't bent. So I pull of the passenger side wheel and mount it on the drivers side and I put the drivers side wheel over on the passenger side. Start the car up again and now there is no wobble in either (well there is a very very slight wobble on the drivers side, you would never see it if you weren't looking hard for it)!?!?!?!

Anybody have any suggestions here???? I have no vibrations at all at any speed and if it were a bent side axle I would have though that I would feel something...and I would have thought that if the wheel was bent I would see it wobble on the passenger side... could it be a combination effect?? Slightly bent rim coupled with a slightly bent flange?

I'm baffled!!!

 

I'd say you should drop the coin for a rearend up grade. There is a tech article here that details what you'd need to do. Might as well go ahead and do it. You'll have a stronger rearend.

https://www.thirdgen.org/newdesign/t...nguprear.shtml

 

Good. I'm getting tired of all the "regular" ones...

Take a close look at the rear wheel bearings. If you have a Saginaw 10-bolt, you'll probably have to remove the center housing cover and 'C' clip that holds the axle in place. If you have a Borg 9-bolt (and I'm guessing that you do), all you have to do is remove the four flange mounting bolts behind the brake rotor, then slide out the axle and bearing. check the axle with a straightedge or mount it between centers on a lathe to check for runout. You may have a bent axle or just a worn bearing.

As for "upgrading" a Borg Warner rear ends, there isn't really much you can do to make them better. They are already a lot stronger than the factory Saginaw axles, so all you need to do is repair what you have. If you need a replacement axle, you might have a little difficulty finding one in a salvage yard. The Borg axles don't last long there, and not many actually hit the market. You can either have the axle straightened, or try to get parts at http://www.9bolt.com/

 

I do have the 9 bolt rear end...

So how does the side axle come out? Wouldn't I have to remove the differential cover and "let go" something in the center? Maybe a clip or bolt or something...

Or will the side axle come out without removing the diff cover...

 

yup. just remove the 4 bolts on the backing plate and voila. axle comes out

 

In the spring when it's time to pull her into the garage and do an oil change, etc etc... I must jack up the drivers side and pull that side axle out....

How hard is it to replace the bearings? Are they expensive?

 

The bearings aren't that hard to replace. But you should probably find a shop that has a press and let them do it. The bearings are pressed on. Some people opt to do it with a hammer. First they take the old bearing off, then slide the new one on as far as it will go. Then put the outer race of the old bearing on top of the new bearing. then they slowly tap it down, working around the whole bearing, not just hammering in one spot, and softly and slowly. it's a little bit slower of a process, but it can work. Personally i wouldn't do it this way. but if there is no other way, well you gotta do what you gotta do. But try to find a shop with a press first. Good Luck
p.s.- the berings aren't that expensive, but you should change the bearing and the axle seal at the same time, both should total about 26 bucks

 

First...I appreciate the comments...it all helps in trying to figure this out...anyway I was thinking (ut ohhh... lol )


If a side axle was bent what way would it appear to wobble? I would think that it would wobble up and down, not side to side....my side axle does not wobble up and down at all...

Here is my theory... please feel free to comment on my theory...

1. The flange with the wheels studs is bent slightly, thus causing the side to side movement...

2. The wheel is bent slightly as well...

3. When the slightly bent wheel is placed on the slightly bent flange both effects combine to make a larger appearing wobble....

4. When the slightly bent wheel is placed on the good side axle the wobble is not noticeable

5. When a straight wheel is placed on the slightly bent axle the wobble is not noticeable.....

Once I get my wheel checked I will be able to confirm my theory :-)

 

Personally I usually opt for the hammer method As long as you are carefull it really is not a problem, and saves money which is important to my peer group (college students lol). IMO the harder part is knocking out the old races....well assuming you don't have I think its called an impact hammer. If you dont have one you have to get behind the old race with some sort of metal rod (A flathead screwdriver will work...just don't expect the screwdriver to be perfectly stright, or unmarked afterwards) there are usually 2 places where I guess what you'd call the seat for the race is cut out. Line the screwdriver up and tap, switch to the other tap...keep going until you can get the screwdriver on all 4 sides of the race where you then alternate between the points. The key is to be patient, and drive the thing out straight. Then as mentioned before, push the new race into place as best you can, place the old race upside down on the new race, and now you'll be hitting the same side of the old race as you were before only to put in the new one. It will be a little difficult but the old race should just pop right out, if it doesn't use a little force, it will give I have done this for my pinion gear bearings (where I learned about doing this) and in my steering column. I dont change many bearings, but I don't think I'll forget about it. I have seen waaaaaaaaaaaaaay too many "mechanics" thinking they are hot stuff change the bearings but not the races which does nothing and drives me insane everytime I see it happen. Thus if I need bearings done, I will do them myself.