Hey Guys, new to the site. I have a 70 Olds "O" style 12 bolt rear in my car with 390's. I am doing a body off on my car which is not an Olds but has the rear. I have been told they are strong rears but have also been told a 12 bolt Chevy is stronger, not sure myself. I am installing a 4 wheel disc conversion kit in the car. I have to replace the backing plates anyway so I have to pull the axles so I cant just clean and paint the rear which is out from under the chassis. The rolling chassis is ready to go together except for the couple of things I need to do to the rear. First, when I removed the cover I found that one ring to carrier bolt was broken and of the other 9 bolts, eight were loose and able to turn by hand. The fact that I didnt find and gear damage or bolt head in case has left me to believe the guy who last touched the inside of this rear screwed up. I will be removing the carrier and replacing all the bolts and using the rear with a Tremec. The next thing is when I removed the axles, they had two different types of bearings, one side had enclosed bearings and the other had a roller bearings and the ends of the axle tubes were shaped accordingly. Is this normal? I am planning on replacing the bearings and seals. What is a rear like this worth to a guy with an Olds because if changing to a Chevy 12 bolt is better and works out maybe thats the direction to go. I know a website that carries all the parts, are there any others?
Thank you in advance,
Bill

 

It sounds like an abortion. Do both axles have a seal on the outside of the bearing,on the shaft itself,or is the seal pressed into the axle tube on eaxh side? So far,it just sounds like you have 2 different brands of axle bearings,and someone didn't use red Lock-Tite on the ring gear bolts & torque them properly.

 

Also ARE the bolts left hand or right hand thread. THIS also could lead to a loosening problem.

Another thing part of the bolt could be in the pinion return oil trough... BLOW that out with air and see what comes out. WEAR eye protection.

If the bolt is left hand thread any 10 bolt 8.5 bolt will work to replace that bolt.

You might want to remove the ring and see if the rest of the bolt can be removed once the ring is off some of it maybe sticking up and you can grab it with some lock pliers and spin it out.

Good luck and let us know how it all turns out. Jim

JD

 

It is left hand thread and I was planning to remove carrier and ring to get bolt out, as far as the bearings the bearings and seals are on the axle, seal on the outside. I will add some pics in a while.
Thank you,
Bill

 

Here are a couple pics.

 

Yes,you have 2 identical axle shafts,but 2 different brands of axle bearings.No real problem there. The part number for the axle bearing is SET-9 or A-9,depending on brand. The seal is # 712146.

 

But they are shaped different as is the insides of the axle tubes so each side only fits its axle. Am I missing something here because to me its round hole square peg.

 

I just spoke to super cars unlimited and he cleared it up. The one side basically fell apart and the outer piece is still stuck in the tube. I will check that tonight.

 

Just checked and pryed piece out, I didnt want to poke around before. Not sure what I was looking at. I guess the different brands is the reason for the different blocking plates. Thanks for the input guys. Is Supercars the guys to buy from?

 

You can get parts & kits from myself,or Monzaz.

 

As Brian said you have to completely DIFFERENT type of axle bearings. MANY companies built bearings back then to take care of these cars.
You have one that is a barrel type bearing the other ( the one with its race still in the housing is a tapered type bearing. Just pull the race out of the housing before you install new bearings. Usually the A9 bearing set is available unless you can find new old stock from other brands like Bower, Timkin, etc.

You are fine as long as you resue them back in the same sides.

Hope this helps

Take care, Jim

 

Brian, would that be the same axle bearings & Seal for a 12 bolt "O" 3.23 rear?

 

Yes,the 70 O-axle has the SET9 or A9 axle bearing,with the 712146 seal.

 

Thanks Brian............