Okay so I just got my hands on a Borg Warner 9 bolt rear end. I want to know all about these axles and research isn't really helping me. What are these things worth I was told they are becoming harder to find. The one I got is a 2.73 posi with disk brakes. And how strong are these axles?

 

A 2 series one isn't worth much. Nobody that cares about swapping a rear, wants gears like that. Which is probably why you were able to get it, for what I assume was, "a good deal".

They are marginally stronger than the 7.5" 10-bolt, but not by a whole lot.

They are virtually ALL posi w disc brakes. Nothing special about that. If the brakes are the cast-iron Saginaw ones, then REALLY nobody in their right mind wants that.

 

The 9 bolt gear is actually a 2.77, not a 2.73. This will have a 2 series Borg Warner 4 pinion differential in it, which will not accept any gears other than the 2.77. You can not put 3.27, 3.45, 3.70 or any other gears in it.

 

That's not completely true...

It'll accept 3.08. :barf:

 

Mine is 3.27. 10 bolt is 3.23. Did you get them the wrong way round?

 

Who are you asking, about what?

 

They are stout rear ends as far as my experience has been. I have a borg warner 9-bolt with 3.27's, posi. It holds my 400 hp sbc just fine. I have a built TH350 with a hard shift kit and my back tires are 275/60/R15's.

Hope that helps.

 

Just wondering why you say, what is the difference and why such a huge problem, wouldn't any disk be better than drums ?

 

Yeah it'd be nice if the world worked that way, wouldn't it?

No, unfortunately, reality is somewhat different from "ideal" in this case. The Saggy brakes have many serious design shortcomings that make them, AT BEST, maintenance-intensive, and USUALLY, completely non-functional. I wouldn't put em on any car I own. There are ways to at least get em to work somewhat, but they'll never be the equal of modern disc systems.

 

89 is the only year good disc brakes (pbr) that were put on the BW rearend.

 

I got ya. Thanks. I guess my best bet is to part it out ?. and hopefully get enough to get a disk break setup.

 

I've never heard of the saginaw brakes, mine has the delco-moraines (which everyone also says are crap) but they perform much better than when I had the 10-bolt with drums in terms of stopping power. Sure I don't auto-x the thing but daily driving was almost a night and day difference.

I agree that they will never be the equal of modern disc systems, none of the disc systems that came on these cars will be (I'd hope 30 year old technology wouldn't be at least! haha)

 

Just wondering if anyone can clear up something for me, somebody in the post above said that there aren't any BW 9 Bolts with anything other than 2.77.

I found this rear end on CL and am thinking about buying it.
http://dayton.craigslist.org/pts/4330957168.html

Can anyone clarify?

 

9 bolts could be had in a few other ratios such as 3:27, 3:45, and 3:70. The rear you posted on Craigslist looks like an ok deal as long as the posi is good and the backing plates are still present.

 

It is between that BW 9 Bolt or this one:
http://dayton.craigslist.org/pts/4340581946.html

What do you think

 

I think your better off with the 9 bolt. $250 is a lot for an open rear and it doesn't even have PBR brakes. The brakes on the nine bolt will not cost that much and it is a stronger rear.

 

Well since it is apparently a 3 series because of the gear ratio, what brakes would I buy. The guy has no info on the car it came from and I'm not sure what cars these came off of.

 

9 bolts usually came on higher end cars such as 5.7 GTAs or irocs. If it came out of an 89 it would have PBR brakes but any other year car and it would have the iron calipers like that 10 bolt you posted. I need someone else to chime in because I am not completely sure but your best bet would be to swap the brakes from your current rear onto that one. If the guy does not know much about the rear, that becomes a great negotiating tool.

 

Yeah the brakes from your 2.73 axle should swap right over as long as you have all the parts. The 9-bolt posi will be a better axle than the open 10-bolt for sure. In fact it sounds like you'll have the exact same axle as me when it's all said and done.

It may be different on the '92 but on my '83 buying brake pads is super easy, because now that I have the 9-bolt (I think it's out of an '87) on mine the front and rear pads are the same part.

 

Well currently I have a 10 bolt from an LS1 with big rear disc breaks, posi and 3.42s lol

But I have to downgrade back to a third gen and I'm trying to get best possible performance with 3rd gen rear end.

I bought new wheels and tires and they won't fit right on my 4th gen because of the extra 2in

 

Oh, haha, that's a nice axle. Man, that stinks. It definitely won't be as tough as the 4th gen but should hold up nicely

 

Well since 10 bolt brakes apparently fit onto a 9 bolt, your best bet would be to swap your parts onto that 9 bolt. Not sure how much you have in your fourth gen rear but you may be able to sell off extra parts and do this swap extremely cheap. Selling the posi unit and gears will make up the cost of the 9 bolt and selling the axle shafts and backing plates will net a few more dollars.

 

You can swap over 4th gen brakes to a 9 bolt?

 

Whoops somehow I missed the ls1 brakes part.If I were you I would put up an ad to trade your ls1 brakes for a PBR setup. Ls1 brakes are desirable and someone might go for them. Otherwise search ls1 brakes on a nine bolt. There are a few threads were it has been done but I only skimmed through the posts.

 

Yes. Search Google or search here.