Has any one swapped their 9-bolt for a 10-bolt rear? Will the 9-bolt's disc brakes bolt right on? I've got an '89 Formula that needs a quick rear end rebuild, but don't know anyone near where i live that can perform this on a 9-bolt, not to mention getting rebuild parts for it.

 

i would leave the 9bolt in there its stronger,been proved a bunch!

 

PBR rear brakes, which I assume you have, are swapable from 9-bolt to 10-bolt, but 10-bolt backing plates are required and you'll likely need shims. Check the following link for the part numbers and general info:

https://www.thirdgen.org/techbb2/sho...hreadid=246768

JamesC

 

Thanks James, excellent link and nice job on your brakes. I need to rebuild all four of my calipers as well. I know the 9-bolt is stronger, but i can build a new 10-bolt witth good axles and a new diff for about $300.

Do the required 10-bolt backing plates only come on disc brake-equipped 10-bolts?

 

There were obviously some PBR factory ten-bolts, which have the appropriate backing plates, but the simpler approach, in my view, is to purchase new from GM. The cost was minimual, $13.34 per.

JamesC

 

How much wider is the fourth gen rear than the third gen?

 

THE DIFFERENCE IS 4''..2'' each side..

 

i swapped my 10 bolt brakes to my 9 bolt. i also swapped 9 bolt brakes to a 10 bolt. i never noticed anything different as far as backing plates go.

 

The 9- and 10-bolt backing plates appear to be similiar, but the bolt pattern is different enough that they are not interchangeabe. See the above link for a comparison. The PBR's themselves, however, are interchangeable between the backing plates.

JamesC

 

oh...... i see
to think of it, i never changed the backing plates. very informative

 

James, if i buy the backing plates and shims, that's all i'll need other than the 10-bolt itself, right?

 

Right. You'll be able to swap everything else from your 9-bolt: the hard lines, soft lines, the driver's side hose bracket, the e-brake cables and cable guides (without these, the pass side cable will probably fry on the intermediate pipe). I list the part numbers for all those above should you need them.

JamesC