Xophertony

I just finished putting the 89-92 style (sometimes called “1LE”) brakes on a 3.23 Posi 9bolt rear end, and then putting that rear into the car. i decided to post up because in all my searching i found very little info on installing these brakes onto a 9 bolt rear. Tons of info on 10 bolts.

BACKSTORY:
I have a 1988 GTA. Came from the factory with discs and 3.23 posi. somewhere in its life someone switched it to a 10 bolt 2.73 drum rear. They did not switch the prop valve so the rear brakes were essentially just for looks

SUPPLIES:
To accomplish this swap I purchased Backing plates, re-built calipers, hard lines, earls braided steel lines, and rotors from Ed Miller (ebmiller88 on the site). I was very pleased with the quality of everything in the kit. I also purchased ceramic brake pads from NAPA.


FABRICATION AND MODIFICATION REQUIRED:
the mounting hardware included with the braided steel lines were not drilled for bolts, so I had to drill two holes in the aluminum mounts, and one of the mounts had a tab that had to be hammered flat. Both of those were easy. The only modification that had to be done to the rear end was some clearanceing for the banjo bolt on the left side. The bolt would interfere, or at least touch the lower "trac-bar" mount on the drivers side. to alleviate this potential clearance/vibration issue a 5LB sledge and a piece of one inch round steel about two feet long were used to make a small (1/8th - 1/4 inch) dent in the tracbar mount.

OTHER INSTALL TIPS AND INFO:
The only other hitch in the install was that the backing plates were mislabeled both on the handwritten labels AND on the "L" and "R" stamped on them. So at first I was very confused as to why my calipers and LCAs were occupying the same space. Once the mistake was spotted and the backing plates were reversed all went smooth as glass.

another thing to keep in mind; the EARLS brake lines come with the mounts that hold the steel lines to the rear end, but NOT the clips that hold the lines into those mounts. If you are doing an 82-88 disc to 89+ disc conversion all the clips you already have will work. If you are doing a drum to 89+ disc conversion you will need to find these clips.

alot of good info on the 10 bolt conversion, and EVERY part number needed for 9bolt or 10bolt conversion as well as alot of awsome pics of a 10 bolt conversion can be seen in this thread:
82-88 Discs to 89-92/Pics and Part Numbers


and this thread has some interesting facts about 89-92 discs as well. https://www.thirdgen.org/techbb2/sho...90#post2714590

Xophertony

i guess i'll link the two jumy pics i have as well.





pics of the "clearencing" are to blury to use, but there is not much to see. it's just a tiny dent in the mount to make room for a bolt. we just continued to hit it until there was no more touching.

ebmiller88

iTrader: (7)

Nice work...let me clear a few things up for you:

The bracket you had to hammer flat probably went on the other side, I make them side specific so that was probably the issue there. My fault for not labeling them for you.

On the backing plates, I label them differently for 9 and 10 bolt use and that's how you should have installed them, and that's why I think you had the clearance issue on the banjo bolt. Had you installed the plates as I labeled them, the calipers would have been clocked in a lower position in reference to the axle flange and the banjo bolt would have therefore been lower, and no interference.

I sent my parts out ready to bolt on and they need to go on as I label them, making install a snap. I should have labeled the brake line brackets for you, my fault. I also leave the small screw hole undrilled as the holes are located differently on drum and disc rears so you are able to put the bracket where you want to.

Ed

PS: Just an FYI, the driver's side hard line should go under the spring perch as pictured in James' thread.

Mongoose

iTrader: (2)

Man,reading that brought back memories of my swap.

Xophertony

ohhh.... you made the brake line brackets? i thought they came from EARLS.. nice. well, that explians that. also, if my rear end had both of them to begin with it would have been as simple as placing your spiffy aluminum ones in the location i removed the nasty steel ones from. and i just remembered, i did the uhm.. "modification" to your hard line bracket while attempting to istall the brakes backwards (calipers facing front of car instead of rear, before we realized the LCAs were in the way ) so it was deffinatly on the wrong side when i did that. meh.. thise little positioning tabs don't realy do anything anyway right...

as far as the calipers go, as the rear sits now the backing plate stamped "L" is on the right side with the "this side in" side in. they should be oriented axactly as you intended. as for the brake line... well.. dang. guess i screwed that up. i was basing it off of the routing of the badly mangled lines that came on the 9bolt. and most of that side had been cut off by some junkyard buthcher who took the caliper and left no survivors.

EDIT* i think we put that brake line on backwords... looking at where the bends are in the other thread, and where the bends are in mine, and remembering the slight tweaking we had to do to get it to fit... yeah... thats kinda funny. meh.. i'm not bleeding the brakes again it stays. next time i am going to hafta loose rear brake fluid i will route it correctly.

BTW just to clairify and restate: ED rules. Eds products rule. (his aluminum brake line mounts reduced my rear unspring weight ) and i will definatly be looking to him when it comes time to do front brakes.. (do those C5s fit under GTA wheels yet ) verry pleased.