Progress On Rear End

With the Subaru differential in hand, along with the rear differential mount kit, we were ready to make an attempt to install it in the car. The first order of business was to remove the OE studs that helped secure the differential in its donor car, as the Birkin would use bolts to mount the aluminum mounting plate.

There was some concern that the thread of the stud would not match up to the thread of the bolts supplied with the Birkin. After pulling one of the studs out, we found we were safe. (We make it sound easy - they are held in by loctite and may require heat. If you take heat to it, be sure to remove the brown vent from the top rear of the differential or it will melt.)

After both studs were out, we mounted the rear differential mounting plate with the supplied bolts. You can see the mounting plate to the right - the pic was taken when the studs were still installed in the diff. Notice the position of the plate. The side of the plate with the spacers face the rear of the car. Also, it's important to note that when you bolt the plate to the rear of the differential, the little spacer (shown on the bolt there) will go in between the differential and the aluminum mounting plate. The washer will go on the outside of the aluminum plate.

There is another plate that mounts to the bottom of the diff, which is held in by four long bolts, some brass bushings and some nuts. This is visible in the pics below.

Here, we have taken the cover off the center console, which is held on by several small 8mm nuts/allen screws. I would think it to be impossible to mount the differential without removing this piece. We're test fitting the lower mount to get an idea of how the differential will fit into and mount to the chassis. We found that the routing and mounting of the two fuel lines and electrical running to the back of the car would not allow for proper mounting of the diff. At all. Not. Even. Close. We snipped the majority of the cable ties holding these lines together and drilled out several of the rivets holding them to the frame and chassis. Once free, we massaged them into a shape that would accommodate the differential. Note that the notch in the back of this lower mount should face rearward, as it coincides with a flange on the diff itself.

Edit: There was really no need to drill out the rivets and go to the trouble we did. After mounting the diff, adding additional spacers in the rear and jumping through a bunch of hoops, we discovered four extra bolts and four extra spacers for the lower front mount of the diff. The spacers were about 1/2" long and went between the frame and the front diff mounting plate. Once in place, all the lines fit fine and everything went together well.

At this point, it was necessary to hook up the rear brake hard lines to the soft lines, which came attached to our rear hubs. The clearance between the hard lines and the bottom of the diff is minimal, but the hard lines can be bent a bit to ensure they don't actually touch the bottom of the diff.

With the fuel lines out of the way and the brake lines attached, we mounted the lower mount on the differential and lowered it in the car. It was easier to attach the lower mount to the diff first, as opposed to attaching the lower mount to the car first. Here is the diff mounted in the car.



Here is a pic of the hard lines under the mounted differential. The bolt holding the rear half of the lower a-arm (to the right in the pic) will interfere with the soft brake line, but the brake lines need to be mounted before the differential - at least to get them in the correct location.

We got the rear suspension together as well. More on that with more pics later.