A car's suspension can make or break the enjoyment of the driving experience. If it's responsive and well tuned even a car with minimal horsepower can be fun to drive through the curves. But a loose suspension can take all the joy out of driving even if you've got a blown big-block or injected Mouse under the hood.
We recently got our hands on a vintage '70 Monte Carlo. The classic's front suspension wasn't in too bad of shape and appeared to have been rebuilt at some time, but the rear underpinnings were down right unsafe. In fact, after we had swapped some larger wheels and tires on it shortly after it was purchased, the suspension's shortcomings became readily apparent. As we pulled out onto a highway, the rearend swayed side to side so much that we pulled over to check that the lug nuts were tight because it felt like the wheels were coming off. A rebuild was definitely in the plans.
Our main objective for this rebuild was to establish a good starting point on which we could later expand. We will eventually upgrade to better brakes and suspension components, but the goal is to be able to test some of these products to find out how much of a difference they make. To do this we needed to build a good foundation. We contacted PST and ordered one of their Performance Polygraphite Super Front End Kits, a center link, a set of KYB shocks, a rear trailing arm bushing set, and coil spring isolators. For less than $700 we had everything we needed to get that old Monte down the road safely. As you will notice, we did not replace the springs or box the rear trailing arms-these modifications will come later.
We gathered up our parts and drove over to Sleeper Suspension Development to have the very capable hands of Jim Sleeper help us out. Sleeper has been working with some of the best-known hot rod and custom car builders for the last few years but has recently set up his own shop again. With a background in setting up race cars and high-dollar hot rods, Sleeper knows his stuff, so our Monte was a walk in the park for him.
Once we got all the necessary pieces from PST, they were given a coat of Eastwood's Spray Grey to make sure that the new parts would stay looking new for a while.
We started tearing the front suspension apart, beginning with the sway bar and immediately spotted one of our problems: The bushings were shot. The entire center link and tie rod assembly was next, and it was removed as a unit and set aside.
The brake caliper was hung from the frame with a stiff wire to prevent damage to the brake hose (although we ended up replacing the old ones anyway). With a jack supporting the lower A-arm, the rotor and spindle assembly was removed. The coil spring was next. Although old coils might not have as much spring as new ones, they can still cause damage coming out. If you don't have a spring compressor, it's a good idea to at least wrap a chain through the spring and the A-arm to prevent it from flying out. The jack can then be S-L-O-W-L-Y lowered, allowing the spring to be pried out.
The upper and lower A-arms were removed and set aside to be disassembled. While the upper arms were out, we inspected its rear frame mount since they are known to develop cracks.
After the A-arms were cleaned up a little, they were put in the vise to be disassembled. The upper arm's cross shaft bushings and the ball joint rivets were slowly knocked out using an impact chisel.
By switching to an impact hammer, Sleeper was able to remove the lower bushing by knocking on the side of the arm surrounding the bushing. It seems like the opposite of what needs to be done, but it works. Think of it as a ketchup bottle, if you tap on the neck instead of on the base, the ketchup will come out faster.
The outer metal sleeves of the new polyurethane bushings were lubricated with white grease and then installed along with the cross-shafts using a hammer and bushing driver. Sleeper applied some silicon lube on the bushing surface and then put a drop of Loctite on the cross-shaft bolts and installed them with the washers. If these were standard rubber bushings, we would've had to wait until the arms were back on the car and down on the ground to tighten them up to avoid preloading the suspension, but the polyurethane doesn't preload so we went ahead and tightened them.
The new ball joints and dust covers were bolted in place, and then the upper A-arms were ready to be reinstalled. Make sure you install them on the correct side. Here's the driver's side upper arm-notice the straighter side goes towards the front.
Before the upper arms were reinstalled, Sleeper put a quick weld on the heads of the crossmember to cross-shaft bolts to prevent them from backing out or loosening at a later time. The upper arms were then installed making sure to use the same alignment shims that were there with the old suspension.
The ball joints and bushings were pressed in the lower arms. Then to ensure that the bushing would stay in place Sleeper applied a tack-weld to them.
Before the coils are reinstalled, it's a good idea to replace the clip nuts that the shocks bolt to. When we reinstalled the coils, we swapped them side-to-side to compensate for some of the Monte's body lean and made sure to place the top of the spring around the raised portion of the crossmember and the lower end of the spring into the dimpled pocket of the A-arm.
Sleeper slowly jacked the lower arm up and installed the new shocks. Then, he bolted the spindle/rotor assembly back in place.
Here's why we removed the centerlink and tie rods as an assembly. We assembled the new parts and adjusted them to approximately the same length as the original parts so the alignment process would go a little quicker. We then installed the entire unit making sure to use the felt bushings for the centerlink. If you have to drive to the alignment shop, this should allow you to do so.
After all the nuts were torqued down and the cotter pins installed, Sleeper lubed the entire suspension. Don't forget this procedure!
With the front suspension finished we moved to the rear. We started by removing the lower trailing arms only. If you remove all the arms, the rearend will have nothing to support it from rolling forward or back and the reinstallation process will be much more difficult.
The bushings were removed using the same method of knocking around the outer edge until they popped out. The new ones were lubricated with white grease and pressed in. Notice the spacer to prevent the arm from collapsing while in the press. The same silicone lube was applied to the outside of the bushings, and then the arms were reinstalled using a punch to help align the bolt holes.
The upper arms were removed next and the new bushings installed. Here you can see the cause of our rearend troubles. The rearend housing bushing was completely shot, allowing one side of the housing to move back and forth.
After the old bushings were knocked out of the housing with an air chisel, the housing bushing ear was heated with a propane torch to expand it slightly. This made it easier to install the new bushings that had been stored in the freezer so they would be a tad bit smaller. They were then knocked in with a hammer and bushing punch.
We had to modify the rearend housing's driver's side thrust washer a little to get it to fit. This must be done when using a 12-bolt rearend. All that was needed was to remove approximately 3/16-inch from one side to allow it to clear the rearend's center section. With that done the upper arms were installed.
The coils were next. We replaced the worn out rubber isolators on the top of the springs with new polyurethane ones and installed the coils, swapping them side for side, making sure they were set correctly around the raised portion of the crossmember and housing pad. The new shocks finished the job. The Monte is now much more enjoyable to drive, doesn't have any suspension squeaks, and is ready to go to the next step when the time comes.