The rear bushings supporting the rear differential on my 2000 Legacy GT wagon were completely shot, so this weekend I decided to replace them. I read several articles on LegacyGT and other sites about replacing the stock bushings with the Whiteline poly bushings, but I decided to go with stock replacement bushings. The decision to tackle the job myself was easy: the Subaru dealer quoted "at least" $650 in labor to do the job, plus $25 for a pair of bushings. I bought the parts
Because there isn't much clearance under the car around the bushings, Subaru recommends pulling the entire rear suspension sub-frame. Going this route allows you to use a standing press to remove the old bushings and install the new ones ones. Though I've had most of the rear suspension out of this car at other times, I wasn't about to repeat that experience. Instead, I fabricated a simple bushing press from components I picked up at Home Depot: a 3' section of 1/8" C-section steel bar, three 1/2" grade-8 bolts (4", 5", and 6" lengths), and an assortment of nuts and washers.
I cut four 3" sections from the steel bar, center punched, and then drilled 1/2" holes through the center. I used two sections on each end for additional stiffness. If you have a welder, you might consider welding the sections back-to-back. The c-section is important for two reasons: it provides clearance for the center of the bushing so that you don't damage it during installation and it stiffens the press. Here's the result:
Put the car up on a lift or jack stands, drop the exhaust, protective belly pan, driveshaft and the rear differential. Next, remove the old bushings. Several articles mention burning out the centers of the bushings with a torch. Mine were so far gone that I just pushed the centers out with my fingers:
Removing the rest of the bushing is a pain but, if you are patient, it is not too hard. I used a hack-saw blade wrapped in a shop cloth to cut each bushing housing. A small reciprocating saw with a fine tooth blade for steel would have made this go a lot faster. Be careful not to cut into the suspension sub-frame. I also draped a shop rag over the ends of the half-shafts to prevent metal filings from eventually getting into the rear differential.
Once the cut is made, it is a simple matter to drive out the remainder of the bushing with a punch and dead-blow hammer.
The new bushings are a slightly different design than the originals. There are additional bumpers at the top and bottom (red arrows) that should keep these bushings from being over-extended, hopefully making them last longer.
It can be difficult to start the new bushings into the receiving sleeves. I found that the new bushings were about 0.025" out-of-round. I used a c-clamp to gently compress the bushing from the sides to restore them to round. I also used a bench grinder to taper the leading edge of the bushing a bit.
The bushings must be installed in the correct orientation. I used a permanent marker to mark the outside of the housing to indicate the proper orientation. There is an up-arrow imprinted in the rubber of the bushing, but you won't be able to see it once you install the press. The bushing also has a front and a back. The side that protrudes from the bushing the most faces the front of the car.
To install the bushing, use a rubber dead-blow hammer to lightly tap the bushing into the sub-frame, keeping it straight. Putting a small amount of axle grease on the leading edge of the bushing may be may be helpful. Install the homemade press as shown below and start turning! You will need to switch to shorter bolts as the bushing is pulled into the sub-frame.
If you aren't using both plates on each end, you should install the extra plate as you drive the bushing home to avoid bending the C-sections.
Reinstall the rear differential, driveshaft, belly pan, and exhaust and enjoy smooth shifting again!