The auction on ebay http://cgi.ebay.com/ebaymotors/ws/eB...tem=1857295584 says that only the 89 9-bolts came with a PBR disc option. Why not the 90's and up? Did they stop putting in the pbr's or the 9-bolts, or what happened?

 

Yes, the '89s were the only 9 bolts with PBRs. GM switched to 10 bolts in the '90 and up rears, which did have the PBRs.

Ed

 

Wow, Now I feel special. I got a PBR caliper setup and then updated to a posi 10 bolt.

 

You meant down-graded to a 10-bolt, right? Considering the 9-bolts are stronger than the 10-bolts. Aw heck, just remove a bolt and you are good to go. LOL

Lon

 

It all depends on how you look at it. I blew a ring gear on a 9 bolt and it cost me $370 for a new ring and pinion set. Then just try to get the right bearings for the axels or carrier. Then get them pressed on the axle. Oh by the way did I mention the posi units on those suck ***. Parts are sooooo hard to find. So maybe they're marginally stronger but I'll take the parts availability along with the performance upgrade parts over the 9 anyday!!

Thanx

 

I'll agree a 10 bolt has less expensive and more readily available parts. I didn't realize the question was "which is cheaper to repair?". Yes, I''ve replaced the ring and pinion (3.45 ratio $125 used), axle seals, bearings and had the bearing retainers pressed in. Yes, small parts (seal & bearings) for a 9-bolt can run 3X more than for a 10-bolt. And YES the 9-bolt posi is superior to the 10-bolts. You can rebuild the posi on a 9-bolt by refacing the front of the cones and you can shim it for how hard you want it to hook up.

Lon

 

For $125 I can get a new name brand ring and pinion set. I can make a 10 bolt posi hook harder than a 9 with some shims and a little trickery too. I would compare it to putting a Dana 44 in place of a 12 or ford 9. It's a question of wich is the smarter long term decision.

 

So if 89 came with PBR's and 9-bolt, does this mean the calipers would be a direct bolt on for my 86 9-bolt?

And they make 3.45 gears for these 9-bolts too? What cars/years came with this option?

 

Nope. The '89 PBR's use a different backing plate. If you can find the backing plates or adapters (which AndyZ28 is working on) you can do the switch.

You'll also have to modify the rear brake lines and e-brake cable. The pre '89 cars use an "opposing" caliper set up on the 9 bolt rear end. The driver's side caliper is on the trailing edge while the passenger side caliper is on the leading edge. In '89 GM changed the design and both calipers are on the trailing edge.