 PST offers upper and lower...  PST offers upper and lower trailing arms for most GM musclecars using a factory four-link-type rear suspension. The bars feature a boxed construction that eliminates twisting, and have polygraphite bushings to reduce deflection. We only installed new PST lower arms and left the stock top units since it&8217s the lowers that cure most of the wheel hop problems. |
 Begin by supporting the car...  Begin by supporting the car off the ground with a pair of jackstands positioned on the frame just in front of the rear tires. Although the rear tires will be off the ground, you can ease installation of the trailing arms by using a floor jack to slightly compress the rear suspension. |
 If your car is fitted with...  If your car is fitted with a rear antiroll bar that attaches to the lower trailing arms (such as many GM A- and G-bodies), remove the bar. Our 1987 Buick had metric fasteners requiring an 8mm wrench and socket to remove the four bolts. |
 Remove and install the trailing...  Remove and install the trailing arms on only one side of the car at a time. Remove the stock arm’s rear nut and bolt (18mm wrench and socket on this car). If you can&8217t slide out the bolt after the nut is removed, press on the bolt end with your finger and use the ratchet to unthread the bolt out of the arm. |
 Removing the front trailing...  Removing the front trailing arm bolt is a bit trickier. There should be a factory access hole drilled in the frame, but you&8217ll need an 18mm or correct SAE-sized socket fitted to a 6-inch extension to get to the bolt head. Use a wrench to hold the nut as you loosen. |
 The stock lower trailing arm...  The stock lower trailing arm will likely be a snug fit, but some tugging should work to remove it. If not, you may have to use a prybar or a large screwdriver to remove the arm. |
 Our trailing arm mounting...  Our trailing arm mounting locations were grunge covered and scaly, so we used a piece of 100-grit sandpaper to remove the deposits that could complicate the new arms&8217 installation and possibly grind into the bushings. After light sanding, we lubed the mounting surfaces with hi-temp grease. |
 Check out the difference between...  Check out the difference between the flimsy stock lower trailing arm compared to the beefy unit from PST. The stock arm&8217s U-shaped construction twists during aggressive driving and promotes wheelhop. Also check the grease fitting, which is for periodically lubing the bushings. |
 The new PST trailing arms...  The new PST trailing arms are an even tighter fit than the stock arms. This may be because the stock arms&8217 bushings were worn out. Getting our arms in place required using a small block of wood and a hammer to tap them into position. |
 The PST trailing arms come...  The PST trailing arms come with new mounting hardware, so we junked our scungy stock metric bolts for new American SAE-threaded bolts. After installation, use a torque wrench to tighten the bolts to 70 lb-ft. Some shops recommend fully tightening the bolts only once the car is back on the ground. |
 Here&8217s one of those tricky...  Here’s one of those tricky steps the instructions don’t talk about--rear antiroll bar re- installation. Our bar was a beefy aftermarket unit that required a fair bit of positioning via a rubber mallet. Each time we hit the bar it would spring back, so we had a buddy waiting with the antiroll-bar-to-trailing-arm bolt so when we hit, the bolt could be quickly slid into position. Even if we had used the stock antiroll bar, we&8217d still probably have to use the mallet method because it was a tight fit with the beefier PST arms. |
 Check it out! Our new PST...  Check it out! Our new PST trailing arms are not only stylin’, but work great too. Of course, in the interest of magazine testing, we did numerous hard (turbo spooling) launches to test their effectiveness. The PST goods earned CC’s official "A-OK." CC |
Installing aftermarket boxed rear trailing arms is an effective suspension mod that most car crafters can do themselves--it's very common on rear-coil-sprung GM cars such as A- and G-bodies from 1964-1988. But as basic as this upgrade is, there is some stuff to consider that the instructions don't talk about. Recently, we installed a set of PST lower rear trailing arms on an 1987 Buick Grand National (a GM G-body), and here we'll tell you what the instructions don't. The arms themselves are different for the late-model A- and G-bodies than they are for the 1964-1972 A-body cars (Chevelles, Skylarks, and such), but the installation procedure is very similar. It's also the same for the arms from the many companies that sell 'em.