Did your car get in a wreck or are they rusted out? If yes, you need to replace the entire arm...Used: eBay or local junk yard or New Acura Parts.
If neither wrecked nor rusted out, you probably just need the 3" rear trailing arm bushing (highlighted). You need either a hydraulic press, some rental tools, and a helper OR take the arms off and bring them to a shop with a hydraulic press. Measure the lip top and bottom of BOTH sides of EACH bushing before taking them out. I used a digital caliper for this because the measurement is very small and very precise. Write these numbers down and check them when you (or your mechanic) are done. If the bushing is pressed in too far or too little, it will stretch out of shape something awful when you get an alignment and the bushings will have a VERY SHORT LIFE. Ask me how I know.
There are three varieties of 3" trailing arm bushing currently available...Chinese rendition of OE (e.g. Mevotech, Dorman, Moog, etc.), Chinese rendition of Mugen (e.g. former NAPA Chassis Part, AC Delco Professional), and polyurethane. I have Energy polys on everything but the TAB. They suck, but they do corner harder. The Chinese OE's are cheap, but weak. You can expect them to last 1-3 years before tearing again. The Chinese Mugen clones are physically heavier and you can expect them to last 4-6 years. If you get one with a "lifetime warranty" you'd better scan your receipt from wherever you got them because none of them have logos or date stamps on them and NO ONE will honor the warranty without a receipt.
Mugen clone...notice the meaty insides, rounded edge, and textured bolting bracket?
Chinese junk version of OE...thin, weak, rubber flashing errors, and no texturing on bracket.
Remember, after you're done replacing whatever (whole arm or bushing), go get an alignment.
In the event that by some miracle your TAB's are in great shape, the only other thing that can go wrong with the trailing arms are the rear bearings. Mine were surprisingly easy to replace when they started making the hollow scratching sound like they do when the bearings are starting to fail. For others who find this thread in the future...here ya go...
1. Removal #12...can also put a lug nut partially on and hit back of disc with rubber mallet.
2. Removal #14...rent a slide hammer to take the hub off.
3. Installation #2...will probably have to turn the brake caliper in and bleed some fluid off to make installing the pads & caliper easier. YouTube it.
4. Installation: all. ...rent a torque wrench(es) (or buy at harbor freight...1/2" & 1/4") to reassemble properly. If you don't have access to a 1/4" T/W, 86 INCH-lbs is hand tight, NOT gorilla tight.