Good evening Bricksters. Recently, tired of listening to the rear axle clunk of my '83 245, I ordered up some new trailing arm bushings from FCP Groton. I also went through the trouble of building the Art Benstein special...the bushing removal and installation tool which is discussed elsewhere here on the board. Then, while browsing catalogues, I stumbled across mention that the urethane replacement bushings require that the old shell be re-used and a lightbulb went on. Sure enough, a message here on the board confirms that you just leave the shell in place, clean out all the junk and put the urethane bushings in. In fact, I was so impressed by the suggested ease of this operation that I ordered another set of bushings from FCPG, this time urethane. Following is a little tutorial. I have not been able to upload pix, but if you e-mail me at dpsam@sbcglobal.net, I'll be happy to send them all.

Chock wheels and use jackstands. Next, it's a good idea to take a moment and study the rear suspension. For the novice, the trailing arm bushings are in the axle housing, not the arms. To get to them you will be lowering the arms away from the chassis and axle. When we change springs in a 240, we get them out by unbolting the lower shock mounting and lowering the arms complete with the axle. However in this case, you must leave the axle supported so that only the arms drop. I put the big floor jack under the axle so it stays put. I recommend dropping the rear muffler from it's rubber hangars and suspending it so it is out of the way (lower) but not dangling, which stresses the whole exhaust system. I used a bungie hung from the bumper shock. Place another jack under the trailing arm so it can be lowered gradually (I did one side at a time). While it is supported, remove the shock absorber lower bolt (19mm in and out). Also unbolt the rear fixing bolt for the stabilizer (anti-sway) bar (17mm). You don't have to remove this bolt, the bar will slide out of the bracket now that the front bolt is out and the rear is loose. Now it's time to unbolt the arm. The bolt head and nut are 22mm. Use an impact hammer inside and a breaker bar with socket on the outside. Adjusting the height of the jack will allow you to pull the bolt out by hand. Now lower the trailing arm and you have access to the bushing. You may have to use a prybar to release the spring from it's upper perch to get the arm to drop far enough. Relax, you can push it back into place by hand. Don't unbolt the spring (unless you have other projects in mind while you are down there) Is the bushing bad? In most cases, if you had a lot of clunking out back, this is the culprit. I have heard of the bushings up front going bad, but I've never had to change any. Panhard rod bushings can also cause clunking, but it is higher pitched. Your first clue that the bushings are bad is if the center tube is offset severely to the top of the bushing. That is, unless your first clue was that the entire bushing was disintegrated and the center tube fell out on the driveway when you lowered the arm. If the bushing is intact, the center tube is bonded to the rubber, the rubber is bonded to the shell, the center tube is centered in the bushing and there is no cracking....someone already changed your bushings! Put it all back together and look elsewhere for your clunk. Maybe your dif is about to explode! Providing the bushings are bad, next project is to remove everything from the bushing shell without damaging it. The urethane bushings go into the old shell and it needs to stay where it is. If your bushing is already falling apart, pull everything out of the shell that you can with a pliers. If, like mine, yours are still somewhat stuck together, they need to be taken apart. The instructions with the bushings say to use a torch. I've also seen this on the board. However one needs to keep in mind that your emergency brake cables and their plastic sheaths are right there. Also your brake lines, calipers....and not to be forgotten, your fuel tank. Use a torch with care. For my car I heated the inside of the tube only, allowing it to be removed with a large channel locks. I used the asbestos shields they sell at hardware stores to protect walls from propane torch flames while you are sweating copper pipe. I put them over the calipers, the fuel tank and the e-brake cables to protect them from the flame. Not that I pointed the torch at them, but the bushings catch fire and the flame goes everywhere. The outside of my bushings was fairly intact. Rather than play the flame on the outside of the shell, I used a drill bit in a die grinder to eat out much of the rubber bushing. Then I chiselled out the rest with a screwdriver. There was still a lot of material bonded to the outer shell. This I removed with the wire brush in the die-grinder as suggested elsewhere on the board. In some areas I used a grinder bit in the die grinder. Tedious, extremely dirty and tiring. Took about forty minutes to get the inside of the bushing completely clean (because mine were still somewhat intact). By the time I was done, the suspension, the driveway and I were all covered in rubber dust and grime. Be careful while drilling out the rubber (if you do). The pieces of hot rubber can fly all over your arms and face, and it smarts. Use eye protection for sure. Next, it's time to put in the urethane bushings. Be careful, there are two per side and they are not alike. The bushing that goes on the road-wheel side of the bracket has a chamfered inner edge. That's because the shell is tapered on one end. You must put the chamfered bushing in from the outside (wheel) side of the car. The kit comes with white grease. Use a bunch of it in the cleaned-out shell, and put some more on the bushing, inside and out. Install both sides and then press the new, steel tube into the center from the differential side. I found that as the tube neared being fully inserted it began to push the outer bushing out. I put a few large washers on an old lower shock absorber bolt, slid it into the bushing, put another washer and a nut on the other end and used the impact hammper and a wrench to tighten it all up. This pressed the whole setup together into the bushing shell. Next, remove the shock bolt and use your jack to raise the trailing arm into place. Watch carefully to note at what point you put the bolt back in from the differential side. In case it fell out, dont forget to put the bracket back on the big bolt that accepts the rear stabilizer bar bolt! Don't bang on the big bolt if you can help it. You will damage the threads on the bolt. As for the rest, in the infamous words of Bentley, Hanes and countless others, "Assembly is the reverse of disassembly". Torque for the large bolts is listed in Bentley as 90 ft lbs (umph!). The shock bolts are 62 and the rear stabilizer bolts are 32. Its a good idea to have the car sitting on a level surface when you snug up the shock and stabilizer bar bolts. This way you can be sure the stabilizer is not preloaded or "tweaked". Take care to see that the rear stabilizer bolts are seated correctly in their brackets before tightening.

For me, the purpose of this test was to see if using the urethane bushings was really a great time saver over removing the entire old bushing, with shell. It is my humble opinion that the bushing press/tool might be faster if, like in my car, the bushings are not badly disintegrated. If the rubber is still mostly intact, the amount of work involved in removing it is considerable. On the other hand, if your bushings are an absolute mess and mostly free of the shell, the urethane bushings could be a breeze. As for performance, my wagon is now completely knock free out back. This car also has urethane torque arm bushings and I notice no unusual harshness in the ride (on KYB gas shocks to boot). In fact I noticed less road noise on the highway now that all the bushings are sound. The rear ride height is also where it belongs, no squat.

I'll be happy to answer any q's anyone has, just e-mail.

DS