Well, were to start here. I’ll start with an overview of my plan. For the rear I will be using 318ti trailing arms out of a ‘98 318ti. I ordered trailing arm bushings and rear shock mounts from Ireland Engineering; and Ben had some AKG subframe mounts laying around so I picked those up cheap as well. As you saw before, I went with IE stage 3 springs, and because of this I ordered 15 mm rear spring pads from bimmerworld (to help get rid of the reverse rake look). To complement the IE3’s I got some Bilstein Sports from FCP Groton as well. So, Lets start with the rear subframe.
-My first mission was to strip down the rear subframe and paint it red to match the front. Once again I brushed and pressure washed the subframe to prep it for paint. Sprayed it with the same primer, and painted it red using a basic Rustolium deluxe base-coat.
Here is a photo of the subframe painted:
-With the subframe painted, it was time to install it. Installation is pretty self explanatory and I didn’t take many photos, but here is the low down for those of you who want to know. The urethane bushing are slightly smaller than the oems so a press is not necessary. The subframe it self has male channels, and the bushings have a female channels. This means, you can’t really mess it up, the bushings only really go in one way. Slide the bushings in from either side, throw the race in and you are all set. With that done you can bolt the subframe right on in.
Here is a shot of my subframe installed:
-With that done, we now have a base to work off of. My next objective was to tackle the trailing arms that I had gotten. I got my trailing arms for Prussian Motor Sport in PA, and they gave me a pretty good deal.
Here is a photo of the trailing arms as they arrived:
First I did my usual cleaning process; wire brush, pressure washer, etc. With that done, I went to town on the oem bushings that were still in the arms. To get the bushings out I decided a torch was the fastest and most efficient way (sorry to all you tree huggers out there). Using an acetylene torch you can melt down the rubber, and eventually push them out using a large screwdriver.
Here are a couple picture of the process just for fun :
With the old bushing out, use a small wire brush to remove any left over residue form the melting process. Now it’s time to install the urethane bushings. Ok, well I found out there are many different ways you can do this, but there is only one really easy way. I searched all over and couldn’t find any instruction on what was the best way to install these bushings so I pretty much did trial and error. Since I had never installed trailing arm bushings before, I figured you just put one side in with the race, and then press the other one in from the other side. Well, that didn’t work so well, even with a 20 ton press (No, i did not apply 20 tons of pressure to my bushings…). So after some different methods I found one that worked perfectly.
First, a couple things to remember: 1- use a good quality grease, preferably with teflon (I used Quicksilver 2-4-c, a marine grease with a teflon base). 2- Install the bushings with the smaller side towards the inside of the trailing arm (it will not fit otherwise. 3- Do not apply an excessive amount of pressure, if it is too hard, check the housing and make sure it is clean, and if it is, use some more grease (you run the risk of ruining your expensive pieces of plastic…).
So, here is how i did it in the end. Take the two pieces of the bushing and coat them with grease. Then coat the bushing housing on the trailing arm with grease. Then Use a C-Clamp and some washers to press both pieces of the bushing in at the same time (NO RACE!). They should go in fairly easily.
With the bushing pressed all the way in, take the race and use the C-Clamp to push it into the bushing (make sure to coat it with grease as well). Once again, it should not take too much effort.
Press the race all the way in until it is flush with the ends of the bushing.
-With all of the bushings finally installed, I moved on to trailing arm paint. I laid a couple coats of primmer down on them, and then some black paint followed. You will see here later that the painting was done pretty late at night and I missed quite a few spots . I’ve done some touch up since then.
These are photos of the painting process:
While the tailing arm paint was drying I tool the few minutes needed to install the rear shocks with the Ireland Engineering rear shock mounts. The process is not very difficult; simply throw the shock mount over the top of the shock and thread the nit onto the top of the shock. Bilstein says to torque this nut to 16 ft lbs; however, I went a bit tighter to really bush the urethane bushings out into the solid aluminum. with that done, hold the shock in place with one hand, and reach into the trunk and put on the gasket, stiffening plate, and nuts that hold it all together.
Here are a few photos of the rear shock mounts from IE:
So, With the trailing arms painted and the bushings installed. It was time to bolt those bad boys into the car. Well, once again (of course), that posed to be more difficult than expected. With nearly solid bushings, expect to spend a bit of time forcing them into the mounts on the subframe. The only real advice I can give here is a bit of finesse and some inevitable brute force. However, I did find it helpful to bolt the trailing arm up to the rear shock, that way you can move it around just enough, but you don’t have to hold the trailing arm up while installing it. Once you get the holes of the races lined up, slide the bolts in, and you are good to go.
Here are a couple photos of the trailing arms installed (my newly painted subframe did get a little beat up, but nothing a little touch up can’t fix):
-Now, with the trailing arms finally installed, I installed the springs. To do this, you will need to unbolt the rear shock (assuming you bolted it up as I suggested). With the trailing arm hanging install the spring pads in their proper location, and then throw the springs in there with the proper orientation. With the spring installed, I had to apply a reasonable amount of force to bolt up the rear shock again, if you didn’t use 15 mm pads, this won’t be an issue; however, I was able to do it by hand.
Here are the pictures of the spring installation process:
Now the rear is ready to take some brakes and wheels! Thanks for reading guys!
-Noble
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