jac113

iTrader: (4)

Hey guys,
I'm looking at getting this used complete "disc" rear locally as a replacement for the drum rear which I assume is a stock 2.77 limited slip. The car is an '89 Iroc, non G92 and the replacement rear end is off of a '88 Iroc.

My only issue is that the 82-88 calipers seem to have a reputation for being problematic. I'm not sure exactly why but have read this in several different threads. The only reason why I want it is mainly for the brake set up b/c I already have a 2.77 BW 9 bolt but the previous owner kept all the brake hardware. I bought that one as a replacement for my 3.42 rear on my 92 but now that I have an 89 with drum rear I want to swap for disc.

Basic question is am I defeating the purpose of buying an extra rear for the rear disc set up if the 88 calipers are garbage anyway? I've even checked with the dealer for the reccomended replacement calipers and they're discontinued.

any comments on this brake assy are apprctd. some my wonder why i'd want to go from 3.42 to 2.77, and I sometimes think the same way but saving gas nowadays is a plus as is the fact that the complete disc rear is $150.

thanks.

JamesC

iTrader: (5)

While the old-style J65 set-up is often maligned on the board, I personally experienced no issues with it. New rotors, calipers, pads, lines--and with frequent use of the parking brake (as in every time you shut the car off)--and I'd think you'd be fine. That said, Ed Miller sells a 'no-hassle' drum to disc conversion for PBR's. Might be something to consider.

JamesC

jac113

iTrader: (4)

Thanks James.
Before I commit to another 9 bolt I wanna make sure I know what I'm getting myself into.

So please correct me if I'm wrong and here's what I have or gonna have in a few hours. One 92 camaro with pbrs and one 89 with drums and both 10 bolt diffs. I already have a 9 bolt with no brakes and am scheduled to get another complete 9 bolt later today.

What I want is interchangeability so it sounds like I can swap the complete 9 bolt in the iroc with the prop valve and be on my way....right.
For the 92, in order to go with the 9 bolt on the other bare-no breaks axle i'll need Ed's backing plate to put the pbr's on the 9 bolt.....right?

Finally, in case I have to rebuild the 9 bolt iron caliber would I be able to get parts from most local parts stores?

Thanks
JC

InfernalVortex

iTrader: (4)

The PBR brakes are better and look better. That's the 89-92 ones. Larger discs, aluminum calipers, etc etc.

The old iron caliper rear brakes work fine Im sure, especially with 20 years of knowledge on how to prevent them from being problematic. But a v6 engine still works to get the car around, too. I dont want something that just works. If all you want is something that works there's nothing wrong with the old style calipers.

JamesC

iTrader: (5)

The 82-88 J65 system (rotors, calipers, pads, combination valve) is identical for both 9- and 10-bolts--and thus interchangeable.

The 89-92 J65 system, where rotors, pads and calipers are concerned, is the same for both 9- and 10-bolts. The exceptions here are that the backing plates are different between the two systems and, though it has nothing to do with whether the rear is a 9- or 10-bolt, there are two combination valves for the years in question: one with M1.0 (fits early 89 down) and the other with M1.5 (fits late 89 up) tube nut threads. This latter won't fit the earlier cars, of course.

A J50 system will require axle flange modification or Ed's kit and the correct combination valve for a specific system--that or an adjustable.

Since the 9- and 10-bolt systems are the same, check out the 10-Bolt FAQ sticky at the top of the page. The brake info (master, combination valve, speedo gears, parking brakes cables and so on) is toward the bottom.

JamesC

jac113

iTrader: (4)

Ok good, I can take advantage of the deal then. With only purchasing two adapter plates and whatever hardware I need to correct the fittings I can have full interchangeability. The complete rear that I'm going to get today comes with the prop valve so will only have to deal with the older fitting issue.
On my 92, if I decide to gear down I just need to get eds backing plate.

Thanks for clarifying.
JC