Maximum Independence

To begin the bushing swap, we disconnected the battery, popped out the rear seat of our Mystichrome convertible Cobra, unhooked the ABS sensors, and pushed them down through the rubber grommets in the floorboard. Then the exhaust was removed from the flow tubes rearward.

To remove the brake calipers, unbolt them from the pad cage, disconnect the emergency brake cables, and maneuver the calipers through the control arms to the other side of the axle.

With the brake calipers on the opposite side, tie them out of the way, unbolt the bottom shocks mounts, and then support the differential and IRS subframe with a floor jack or two. Friends come in handy during this stage.

Unbolt the rear subframe bolts and allow the IRS unit to swing down to a stable position. Remove the front two subframe bolts and pull the IRS out from under the car.

An easy place to start the transformation is the rear antiroll bar. The MM kit includes new urethane bushings, and we also chose to install the company's adjustable sway bar end links.

With the antiroll bar removed from the IRS unit, replacing the bushings is a fairly simple proposition. Be sure to use the included plastic gloves when thoroughly greasing up the new bushings, as the grease is extremely sticky.

The adjustable end links are direct replacements for the stock pieces, and will allow you to adjust preload out of the sway bar. If your sway bar is preloaded on one side or the other, it does not work equally on both ends and your car may handle differently from left to right.

Now that you have some momentum going, it's time to tackle the tough part. Swapping out the subframe bushings requires you to file the pin inside the bushing crush sleeve, so you can slide the threaded rod that comes with the MMT-6 subframe bushing removal tool.

If you don't have that tool, you can drill the bushing and walk the drill bit around the outer edge. This method leaves more rubber inside the subframe for you to clean out later, so we got the tool and drilled a few pilot holes to help the tool work easier.

You need to lube up the threaded rod with antiseize or grease of some sort, as you'll be exerting a lot of torque on the tool to get the bushings out.

With the bushings out, clean the inside of the subframe shells completely. We used a wire wheel on a drill to hone them out. We've also heard of people using brake hones successfully.

Break out your latex proctological gloves, grease up the bushings inside and out, then insert them into the subframe. If they are tough to get in, you may need to hone out the subframe a bit more. Ours went in without a hitch.

Once you have swapped out all four subframe bushings, it's time to move on to the lower control arm bushings. Maximum has another handy tool for these, and it works more easily than the subframe bushing tool. Chalk that up to the factory's bushing installation method. Follow MM's instructions for adjusting the control arm bushing shims, and you're almost ready to reattach the control arms.

Before you can do that, though, you need to check and see if your car is equipped with these support washers. If so, you'll need to grind them out with a die grinder or cut-off wheel. A hacksaw will work in a pinch, as you only need to break the tack-welds.

Removing the upper control arms begins with marking the eccentric upper bolts. This way your camber won't be FUBAR when you put it back together.

To remove the upper control arm bushings, grind off part of the original bushings.

With the rubber bushings out, clean the inside and outside edges with the supplied Scotch-Brite pad.

Next up are the differential bushings, which we opted to replace with MM's MMIRSB-40 aluminum bushing kit. Plug the vent tube and tilt the IRS up on its backside. Remove the subframe crossmember and the front differential bushings.

Unbolt the spindles and pop out the axle shafts per the instructions. Then you can unbolt the rear differential mounting bolts and hoist out the diff.

You'll need to remove the driver-side tie-rod end to access the rear diff bushing.

Install the new aluminum rear diff mount followed by the differential itself.

Maximum sent us both urethane and aluminum bushings, but we went straight for the stiff stuff. No need for deflection here. Be sure you employ the same bushing types fore and aft, as a mismatch will not properly control the dynamics of the floating rear differential.

With the subframe, control arm, and differential bushings installed, it's time to pop the IRS back beneath the Cobra. Prior to that, we deburred the torque boxes to protect our new bushings from being torn up by excess manufacturing slag.

Raise the IRS evenly and install the front bolts first. We used MM's low-profile bolt kit for the rear, which offers greater tire clearance and protection.

The adjustable tie-rod ends are next. Remove the top nut and tap the ball joint out of the spindle. Then just unbolt it from the subframe.

Maximum's adjustable tie-rod ends allow you to readjust the bumpsteer curve of the IRS, as the factory setting will not take advantage of the stiffer bushings and subsequent reduced movement. While we don't have the opportunity to spell out how to adjust the bumpsteer curve in a couple of captions, Maximum provides good instructions on how to do so with its bumpsteer gauge (MMT-4).

Wheelhop no more-our Cobra's IRS is as stiff as you can get short of a solid axle, and we noticed no degradation in ride quality or increase in noise/vibration and harshness.