Several forum members have successfully swapped front Gen2 3.5L calipers and caliper brackets onto their Gen1 3.0 trucks using the original Gen1 3.0 rotors. It was suspected that the Gen2 3.5L rotors and dust shields would also swap, but no confirmation. They do--the only modification required is the dust shield. The Gen2 dust shields need to be trimmed to allow the lower portion of the Gen2 bracket to mount on the Gen1 knuckle. The rotors swap directly. Also, it looks like the Gen2 hubs can be swapped on a Gen1; there are just a few differences.

Difference #1: the Gen1 has notches which appear to have no function in 3 of the six points where the locking hubs mount. Gen2 on the left, and Gen1 on the right.

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The Gen1 hub looks slightly bigger in diameter in that picture but it's an optical illusion; the measured circumference is the same.

Difference #2: the top portion of the hubs have some differences in grooving. On the Gen2 the optional ABS ring would mount in that area. Since the Gen1 wouldn't use the ABS ring, it probably doesn't matter. Gen1 on left, Gen2 on the right.

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Note the dimension from the top to the bottom of the hubs are the same.

Difference #3: the Gen2 has a thinner ring where the wheel mounts. Therefore the wheel would be slightly farther in (about 3mm) toward the frame if used on a Gen1. Same picture above.

Here's a comparison of the rotors. The distance from the hub mount to the top of the rotors is the same, but the working portion of the Gen2 is obviously thicker, with wider cooling vents in the center. This is the thicker Gen2 3.5L rotor. 27mm as compared to the 22mm Gen1 3.0L rotor.

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Also, the hub bolts for the Gen2 3.5L are shorter than the Gen1 (46mm vs. 55mm) The bolts from the Gen1 can't be used to mount the Gen2 3.5 rotor because the threads don't go down far enough for the nut to secure the rotor.

The road test after installing the full Gen2 3.5L brake setup (calipers, caliper support, dust shield, rotor) went great. I didn't do any agressive braking because I haven't broken in the pads yet, but even light braking seemed improved over the original setup. <img src="/forums/images/graemlins/kewl.gif" alt="" />

1990 Monty LS 3.0 A/T LWB. KYB front shocks, OME rears and coils. 33x10.5 BFG Muds. 5.29, 2.85, RD110, RD46. 2 bouncys. Aisins. Monte Disco swaybar disconnects. GenII t-arms, idler arm, UCA's, V45W front brakes. 2in BL.