84ZZ4

I don't know, maybe someone does.

I know the master cylinder will be different, since the '82-'88 drum rear M/C is the same part number as the one used on ALL '89-'92 cars.

Obviously, rotors, calipers, brake pads, and backing plates are different.

But what about hidden little pieces?

84ZZ4

Found some information on this. When I get around to it I'll probably copy it here: http://www.isthq.com/%7Edan/1LEbrake.html

ws6transam

Yes, that's my third-gen performance page.
I'll see what I can do to convert it to text for the FAQ. Since I'm the author, I'd rather you let me do it.


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'84 Trans Am WS6/L69
KB SFC, Moser axles, Torsen Diff. Poly suspension, Braided stainless brake lines,
5-point racing harness, Koni struts, 11-inch rear disks,Spohn Adj. torque arm,
Ported 305 heads w/1.94"intake valves, Comp Cams XE262H, Griffen alum. radiator,
Speed-sensitive steering conversion, underdrive pulleys & more. 1.05g skidpad verified.

ws6transam

I don't like to criticize the designers of the F-body, but they never did get around to making decent brakes for these cars until the 1989 1LE package. In fact, I think these brakes should have been on every single V8 RS, Z28 and Trans Am. My 1984 T/A had the original J65 rear disk system, which in my opinion, was never a very likeable braking system. They use the original 10-inch J65 disk brake system up to 1988. This year I finally ripped out the original rear disk system, and upgraded to the 1989-up J65 disk design. It's not a matter of removing the calipers though: I replaced everything except the hard lines. Master cylinder, roportioning valve, the works.

Here are the project notes for my J65 rear disk upgrade project. I installed these brakes in the later winter/early spring to correct what I percieved as a chronic list of problems with the original '82 through '88 J65 rear disk system. My plan was to have decent brakes that would hold up to the rigors of an open road race track. I eventually did get the car to Gingerman raceway where I happily went through half of my brake pad thickness. The race tires, brakes, and suspension changes resulted in 1.05 g sustained lateral acceleration, and enough braking forces to actually make my copilot queasy.

Here's the parts for the rear brake installation.

10 bolt axle housing, with disc brake flanges(Qty 1)
10087702 Rotor (qty. 2)
10132831 PBR Caliper, LH, Purchased used (Qty 1)
10132832 PBR Caliper, RH Purchased used (Qty 1)
14047782 Brake hose bolt (Qty 2)
10136853 Mounting bracket , LH (Qty 1)
10136854 Mounting bracket, RH (Qty 1)
Bracket shims (Generally one per side)
26013017 0.81mm thk
26013018 1.57mm thk
26013019 2.33mm thk
10164125 Emergency Brake cables, 1st design (qty 2)
Brake Pads, source for GM 1989-up 1LE application (Qty 1)
14089496 Combo valve, 1989 1st design: M1.0 tube nut threads (Qty 1)
18014286 Master Cylinder, Required only if replacing 1982-1988 rear disk system. (Qty 1)
(Same as the J50 option drum brake equipped cars from 1984-up.)
Braided stainless Brake hoses (Qty 1 Kit)
I used Earl's but the more popular one is Russells.
30" brake tubing for left side: (Qty 1)
Metric thread. Standard GM stuff. It will require a tube bender. The mounting of this tube and the brake hose will require you to braze a
bracket onto your axle tube.
axle gear lube. (Qty 2 Qt.)
differential gasket. (Qty 1)
Axle seals (Qty 2)
3/8" NF Grade 8 or better, 1.25" bolts with nuts, and lock washers, for the brackets.(Qty 8)
loc-tite 242.
Strong sense of self-confidence.
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To accomplish this install, you have to pull out the axles. I've never done it before, and it wasn't nearly as hard as I thought. You remove one bolt, and the center pin falls into your hand. You push the axle inwards, and the C-clip falls out. The axle now slides out. Take care not to crush your seal.
Aw, go ahead. mangle that seal! Resist the temptation to use it again! Get two new ones! Don't install them until AFTER you assemble one more time.

Once you get your parts, bolt everything up and install the axles. Install the centerpin, and tighten the lugnuts onto the rotors. Check your clearance on the bracket cage to the rotor. You don't have to put the calipers onto the cage, just bolt the cage to the brackets. You need equal clearance on either side of the cage; This is about .060". Insufficient room means that your rotors will get scored badly by the rubbing of the cage. Measure your required offset, then fabricate the proper thickness shims. The GM shims have been discontinued as of January 1999. I ended up making my own with a die grinder and a piece of .032" brass shim stock. Took about 60 minutes per shim. These are necessary to center the caliper bracket cage on the rotor. They fit between the mounting bracket and the axle tube flange. My right side brake needed one .032" shim, while the left needed the 2.33mm (.091") shim, which GM (luckily)still had in stock. Remove the axles again,
install your new seals and shims. Torque down your brackets with loc-tite, re-mount the rotors and cages, and re-check clearance. You can now proceed with the rest of the assembly.

Note that the routing of the new parking brake cables is over the top of the axle on both sides. The right side may need to be tied to the axle, and retained onto the body with a steel retaining bracket in order to clear the exhaust. If you skip this step, you may melt the cable on your exhaust causing premature failure.

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'84 Trans Am WS6/L69
KB SFC, Moser axles, Torsen Diff. Poly suspension, Braided stainless brake lines,
5-point racing harness, Koni struts, 11-inch rear disks,Spohn Adj. torque arm,
Ported 305 heads w/1.94"intake valves, Comp Cams XE262H, Griffen alum. radiator,
Speed-sensitive steering conversion, underdrive pulleys & more. 1.05g skidpad verified.

84ZZ4

Thanks, some of that stuff is bound to be a little different for me, since I'm installing onto a 9" rear instead of a 10-bolt... but the info is much appreciated.