Trailing Arm Bushing Replacement

[artwangler]

I recently recently up-graded the trailing arm bushings on my '74 911. Here are two things I did that worked for me.


1) to remove the 'outer shell' of your old bushing from where it is press fit into the aluminum tailing arm, you can make a simple tool from a bolt, two nuts, and a washer. The bushing comes in two halves that are pressed in from either side of the aluminum arm. There is a very thin gap where the halves do not quite meet in the middle. In order to press out the steel shell of the bushing, you need to get a 'pushing' tool into that gap. A drift punch does an ugly job. Instead, grab an 8mm bolt, about 3" long. Thread on a nut, about 3/4", then a thin washer, then another nut and then tighten the nuts to hold the washer securely. The outer edge of that washer should be thin enough to fit into the gap between the two halves of the bushing shell. It ought to give you a solid purchase to tap on the edge of the steel shell. (Once the shell begins to slide out, and the gap gets bigger, you might want to change to a bigger bolt and a bigger washer to get even more grip on the thin edge of the shell.) If the shell won't come loose, avoid introducing open flame onto the aluminum. (Aluminum softens at a fairly low temp and can bend easily when struck.) Instead, get a can of Dust Off from the office supply store. If you turn the can up side down, you can squirt its liquid contents directly onto the steel. This will flash freeze and shrink the steel shell. If you decide you need to heat the aluminum too, use a heat gun on low, or a hair dryer on high. Once it is warm, squirt more liquid Dust Off onto the steel inner shell and quickly apply force with your custom tool while the two materials are still at dramatically different temps.

2) When you re-install your trailing arms, with their renewed bushings, into the mounting brackets located on the torsion bar tube, you may find it is a very sung fit. Perhaps too snug. In order to spread apart the sides of the brackets, you can make a simple custom tool. You'll need a carraige bolt, about 1/2" by 3 1/2" (any bolt will work, if it has treads along its entire length,) also, two nuts and two beefy washers. (The washers from you old bushings are perfect, if you can separate them out.) Slide the bolt through one side of the bracket, then place on one washer, then 2 nuts, then the other washer. Now push the bolt further until it pokes out of the hole in the other side of the bracket. By spinning the nuts in opposite directions, you can spread open the bracket enough to fit the trailing arm with its fat new bushing. (One side of the bracket is heavy steel, the other side is thinner. So, only one side of the bracket should actually move. Thereby keeping your geometry correct.)

I hope this is helpful.

[jjeffries]

Am about to do this, thanks for the advice. The best mechanics always find neat ways to get the job done with minimal damage, pain and frustration. Your solutions fit that definition. John in CT.

[Tidybuoy]

Thanks for posting this! I'm doing my '74 this weekend.

Question: I'm assuming I have to remove the banana arms from the car as I have not been able to get the ends of the arms out of the carrier.