New thread since its not a brake problem..... ended up raising the car up from the rear end..took my rear wheels off and put the car on Drive with the rotors tightened on......

When i put the car in Drive... I noticed the whole rotor would Wobble which was causing the pads to hit back and forth and make a squeaking sound....The wobbling disc looks bad .....the right side doesnt wobble...
I even changed the rotors from left to right,,but its still only the left side with the wobble..doesnt sound like a bearing, only sound i hear is the pad coming in contact with the rotor every time the wheel wobbles.

I read this in another thread on here about 9 bolt borg warners
""All 9 bolt rears for f-bodies use 28 spline axles.
Another advantage over the 10 bolt is it uses pressed on tapered axle bearings allowing the axles to be bolted in instead of using c-clips.""


Now my question is....what part do i need to change to fix this ??
The mechanic said its the Left side Axle Shaft that is bent... ?? As i stated before i have a 1989 Borg warner 3.45 rear end disc posi...

Is it possible for the axle shaft to be bent?

 

bent axle quite possible,car sliding into a curb real hard or involved in an accident likely cause...you will need to obtain a used axle with the bearing still in good shape and install(check the bearing race in the end of axle tube too to make sure it is still good)If the axle bearing is damaged,a new one can be installed but a press and special tools may be needed-i have never replaced a 9-bolt axle bearing,but in addition to the pressed on bearing there is also a retaining ring pressed on after the bearing.

 

I did get hit ..someone backed into my rear left quarter panel..(my dad)..didnt really squeak then,,,up until i put the new rotors and pads..maybe they were so wasted before that it wasnt coming in contact.

I have this link...i dont want to go through the hassle of finding a used one. i found this link....

http://www.newgmparts.com/parts/1989...diagram=MHP100

so i guess from this diagram i will need #1 #2 and #3......which would be the axle shaft, axle seals and axle bearing ?

 

would take a major impact to bend the axle,but since the rotors are new best to check runout right on the axle flange before getting the new axle-a lot of new rotors are junk chinese crap and have major quality problems...If you get the new axle(looked like G-body rearend shown in exploded veiw,doesen't show all the 9-bolt parts) you may still need to salvage the axle retainer plate off the old axle if that is not avalible new.An axle shop could press on the new bearing and retainer ring.

 

Stock Delco's I assume - how did you 'tighten' the rotors without the wheels on - there's no retaining screw or bolts, just the wheels and wheel nuts hold them in place if I remember correctly - am I wrong? There's nothing to stop it running out of round without the wheels on.

Also - maybe some crud caught between the rotor and hub?

 

i just found this video it sounds looks exactly alike !


sorry if this is a dumb question? if the axle flange is bent...do i need to buy the whole axle shaft? ...or can the axle flange be bought separate ? is this it http://www.gmpartsonline.net/parts/1...ANION%20FLANGE ??

 

Doesn't take a "major impact" at all to bend an axle... they're surprisingly fragile.

It's quite common, really.

Only solution is to just change them out. Problem of course, is findong a good one. AFAIK on the 9-bolt it doesn't matter what year you get, any from out of one of these cars (85-89) will be the same. The left one is different from the right in that model of rear.

Worthwhile to verify that the rotor is OK though; just swap them left to right and see what happens.

 

Take the rotor off & do the on-jackstands drive thing.
If it wobbles laterally, get a new axle. If it wobbles vertically or fore-aft, check the bearings; if fine, get a new axle. If it doesn't wobble visually, check the rotor centre opening to the indexing hub of the axle.

If you order online instead of going to a local supply house, make sure you communicate explicitly the RPOs, ring gear bolt count, axle spline and gear ratio. That way if they send you 10-bolt parts, you have some recourse.

 

thanks for the info sofaking....so this one will be it right?
http://www.newgmparts.com/parts/1989...diagram=MHP100
with the 7.75 ring gear...? ...from what i read thats what the 1989 9 bolt has? i did try swapping the rotors and its the same thing.

 

Yup, sounds like it's axle time; yup, what we call the 9-bolt, GM calls the 7.75"; and yup, the thing in the pic looks like it ought to be the one. No promises on whether it will actually appear if you order it, but best of luck to ya if you decide to try!!

 

thanks sofaking...one last thing....any other places you would know of that i can order from?

 

No idea... good place to start would be the site you linked to. www.gmpartsdirect.com might be another.

 

Does your car vibrate, shake or wobble driving down the road? I guess another thing you could do is remove the rotor and put the car in drive on jack stands and see if the flange is bent. Could be tricky to do that since you couldnt press on the brake with the caliper off the rotor. Might be able to see if its bent just by having someone turn the right side wheel and watch the left side axle flange. A bent axle or flange I would think would shake or vibrate wildly while driving. If it drives ok but the brake pedal pulsates like crazy, I would look at a rotor issue like something behind the rotor causing it not to lay flat against the axle flange. Something to look at before tearing into the rear.

 

ok this is the last ? for you really......is the axle shaft all i would need when replacing it? ...or do i need to replace the axle seal or can i reuse the one there?

 

its not exactly smooth but is noticeable at speeds over 65 70...car doesnt pulsate when i brake.

 

Gotta replace the bearing and the seal. They come out with the axle, and even if they don't get destroyed trying to get them off the old one, they're 20 years old now with however many miles on em. And of course the bearing took the same hit that bent the axle. So yeah....

 

ok thanks...and thanks for the website you gave me...its actually cheaper than the website i had.

 

Moser makes replacement axles for the 9bolt