BMW E30 Replacing the rear subframe bushings

Well it was time to replace the subframe bushings on my eta. I could tell because I would often get a loud clunk when starting off, and when cornering hard I could feel the rear wheels change position. This would cause the back end to swing out. I decided to take the long route (remove the entire subframe) since I had some other work to do and I have a beater to drive so I could take as long as I wanted. Since the procedure was long, I've split it out to make it a little easier to follow each step.

One note, when putting it back together, don't forget to bleed the brakes and torque the axle nut once the car is on the ground.

Loosen the drive axle nut
Remove the muffler
Remove trailing arms
Remove the differential
Remove subframe
Replace bushings

A few torque values

M10 Subframe bolts ................................... 42 Nm ...... 30 ft-lb
M12 Subframe bolts .................................... 77 Nm ...... 56 ft-lb
Shock to trailing arm .............................. 72-87 Nm ...... 52-63 ft-lb
Sway bar link to trailing arm .................. 22-24 Nm ...... 16-17 ft-lb
Brake line unions .................................... 10-15 Nm ...... 7-11 ft-lb
Rear pad carrier to trailing arm ............. 60-67 Nm ...... 44-49 ft-lb
Rear caliper to carrier ............................ 30-35 Nm ...... 22-25 ft-lb
Upper differential mounting bolts ...... 110-123 Nm ...... 81-91 ft-lb
Rear differential mounting bolt ............... 80-87 Nm ...... 59-64 ft-lb
Driveshaft to differential ................................ 72 Nm ...... 53 ft-lb
Output flange to drive axle ...................... 58-63 Nm ...... 42-46 ft-lb
Muffler bracket ............................................... 14 Nm ...... 10 ft-lb
Front exhaust pipe to rear pipe .............. 22-24 Nm ...... 16-17 ft-lb
Axle nut ................................................. 195-210 Nm ...... 144-155 ft-lb
Lug nuts ........................................................ 100 Nm ...... 74 ft-lb

Parts list (and approximate prices)

2 Subframe mounts 46.00
2 Subframe locking nuts 4.52
4 Control Arm bushings 60.00
1 Exhaust gasket 3.50
2 Sets of Pagid Brake pads 43.00
2 Rear rotors 56.00
2 Rotor set screws 3.80
2 Rear sway bar links 35.50
2 Axle lockplates 2.40
1 can ATE brake fluid 11.95
2 Differential output flange seals 28.84
1 Differential rear cover gasket 2.57
1 Speedo sender O-ring 0.67
2 Crush washers 1.50
2 quarts Redline 75W90 19.54
Various self locking nuts 7.00

Total 326.79

Loosening the drive axle nut

Before starting anything, the Bentley recommends to loosen the drive axle nut with the car on the ground, so you don't topple it off your jack stands. However, this is where I hit snag number 1. Whoever worked on the rear end last (not me -- honest) didn't have a lockplate for the driver's side nut, so they decided that they were going to take out all their aggressions torqueing that nut down. The sucker wouldn't budge. The other problem was that with the wheel on, the nut was too deep causing the breaker bar to be at an angle such that when I was loosening the nut, the socket kept wanting to slip off. An extension would cause the same problem and this was NOT a nut I wanted to strip!

Note bad angle of breaker bar

Then I simply jacked a block of wood up to the muffler to keep it from falling on my face while loosening the lower bracket. Once the bracket was disconnected, I just removed the whole muffler assembly from the rubber hanger and it droped right out. Getting it off the hanger was causing me a little grief, so I just bent the metal tab on the muffler foward so it would slip right out.

Jack handle being used as cheater bar.

The passenger's side was easier as it had a lockplate and the nut wasn't nearly as tight. The lockplate was rusted in pretty good, but some prying with a small standard screwdriver and some pulling with needle nosed pliers did the trick.

Removing the muffler

Removing the muffer is probably one of the easiest tasks. If you haven't removed it for awhile, you might want to check and see how rusted the nuts and bolts are before you start. If they are in pretty bad shape you can spray some penetrating oil on them and let it sit for a couple of hours. I also always try and use 6 point sockets with rusted bolts, because I HATE stripping them. Since I had recently replaced my muffler, everything was in pretty good shape.First, I just removed the three nuts at the union behind the catalytic converter. I left the bolts in to help keep the pipe from dropping while loosening the braket around the muffler.

Nice focus eh?

Then I simply jacked a block of wood up to the muffler to keep it from falling on my face while loosening the lower bracket. Once the bracket was disconnected, I just removed the whole muffler assembly from the rubber hanger and it droped right out. Getting it off the hanger was causing me a little grief, so I just bent the metal tab on the muffler foward so it would slip right out.

Removing Trailing Arms

The first step is to remove the drive axles. This is pretty easy. Remove the axle nut, if you haven't already. I took an old closet dowel that was laying around and sawed about 8 inches off the end of it.
Then I put it against the axle and hit it with a mallet. Once you get the axle pushed far enough in, you can grab it from behind and pull it out.

In order to remove the rear trailing arms, you'll pretty much need to disassemble the rear brakes. The first step is to loosen the caliper bolts. Again, I recommend using a hex socket as opposed to an allen wrench. The allen bolts are 7mm and are in there pretty tight. They loosen fairly easliy with a wratchet though. Once the bolts are all the way loose, simply pull the caliper off the rotor. Don't let it hang from the brake line though.

Then you'll need to remove the caliper carrier. The bolts are 19mm. Using a good breaker bar, they break loose fairly easily. Once the bolts are completely loose, remove the carrier.

Next is to remove the rear rotors. I let the set screw soak in some penetrating oil for a couple hours. Again, you'll want to use a hex socket to remove the screw. It's a 6mm. Hopefully the screw will come out without too much grief. Once it was out I gave the rotor a couple of good whacks with a hard rubber mallet and it popped right off. This would also be a good time to replace your rear rotors and pads since they are already off.

There isn't really a good way to describe disconnecting the parking brake cable, but that's what you'll need to do next. Just make sure the parking brake is NOT set. Of course, you probably would have had a little trouble getting the rotor off if it had been set. Remove the lower return spring and spread the brake pads out a little. Once you do that, you'll see how to disconnect the cable. I would also suggest putting a paper towel under the brakes, because a couple small metal pins will fall and if you don't have anything to catch them, they might disappear forever.

Disconnect rear anti-sway bar from the trailing arm. It's one 13mm nut on the bottom of the trailing arm. This is a step that the Bentley forgets to tell you.

Bleck, that's a messy picture

Disconnect the brake line at the union towards the front of the trailing arm. You'll need a 14mm and 11mm wrench. I used flare wrenches so as not to strip any of the connections. Also, if you have a bucket handy, I would put it under the union before disconnecting, because brake fluid will drip all over the place.

Arrgh, nice focus

Now it's time to remove the bolts that hold the trailing arms to the subframe. All the nuts and bolts are 19mm and it's a very tight fit. On the very outmost nuts I used a 19mm flare wrench again, because it was the only wrench I could fit in there. Then I monkeyd with extensions and a wratchet on the inner bolts till I found a good fit. On the passenger's side you will have trouble getting the outer bolt out, because the gas hose is in the way. However, since I was dropping the subframe anyway, I just left the passenger side trailing arm connected and when you drop the subframe a little, it will give you enough clearance to pull the bolt out. Once all the bolts are out, simply remove the trailing arms.

As you can see, it's a tight fit.

Removing the differential

The first thing to do when removing the differential is to disconnect the drive axles from the output flange. For this you want to use an 8mm Hex socket, not the L-shaped allen wrench. Trust me on this one. I thought I would save 5 bucks by using my existing allen wrench and it didn't work worth a darn.

So, once I got the 8mm Hex socket I began the ardous task of setting the parking brake, climbing under the car, loosening as many bolts as I could reach (usually 2-3 a side), climbing out from under the car, releasing the parking brake, turning the wheel until more bolts were in the clear, setting the brake again, and so on. Once I got all the bolts completely loosened, I simply removed the axles from the output flange and suspended them with some heavy duty wire.

My differential's vain, so I got it's good side

Next I removed the 4 self locking nuts that hold the driveshaft to the input flange of the differential. I used pretty much the same procedure as above. Had I thought ahead, I would have loosened them when I was loosening the axle bolts.
They were a little too tight for me to loosen using the combination wrench by itself. I didn't have enought clearance to fit a cheater bar in, so I took a very large monkey wrench and tightened it up against the open end of the combination wrench. This gave me the leverage I needed to break the nuts free. Those who do this professionally probably think this looks a little wacky, but hey, it worked for me.

Is it my imagination, or is the garage slightly tilted?

The next task was to loosen the bolts that hold the differential in place. Remember that we are not actually removing the bolts yet, just loosening them a turn or so to make life easier later. The Bentley mentions that you need to remove the 2 front mounting bolts. Well, on my car there are actually four. The two bolts that are on the top have very little clearance and there was no way I could get a breaker bar up there, or use the trick with the monkey wrench, so I just had to use all my strength to loosen those guys up.

The lower 2 front mounting bolts had enough clearance to fit a breaker bar in. It was a tight fit, but it was enough to get them loose and use a smaller ratchet later on. The rear mounting bolt is very easy to get at so that was no problem to loosen.

Yowza! That's a busy picture

With all the bolts slightly loose, it is time to support the differential and remove all the mounting bolts. Fortunately I already had a transmission jack adapter that I was able to use. I jacked the adapter right up to the differential so that it was supporting all of it's weight. I completely removed the 4 front mounting bolts first and then I removed the rear mounting bolt last. The last step before lowering the differential is to disconnec the speedometer sending unit. It's the little plug on the back of the differential. Finally, I lowered the differential, while holding the driveshaft foward so the differential input flange wouldn't get caught up on it.That's all there was to it!

Removing the subframe

Well, removing the actual subframe is actually pretty easy. First remove the two hex bolts on the side of the car. Once again, my theme for this is repair is what? "Use a hex socket". Ok, I'll quit with that already. These guys are 6mm. Then remove the 22mm nut that holds the support plate in.

Humm, are the evenflo boxes a giveaway that I have a baby?

Spray a little penetrating oil on the subframe pin from the top. You'll have to remove the rear seat to get at it.

You can see I've already popped the post up.

Once the oil has had a chance to do it's thing support the subframe with a jack. Then simply whack the pins from underneath with a hammer. For me it was about 3 whacks and they popped right out. I read in the FAQ's to put a towel over the bolts in the car so they don't don't go flying around your interior. I forgot to do this, but I didn't whack them hard enough to send them flying.

Once the pins are out the subframe simply drops out. You'll have to do a little maneuvering to get past the driveshaft, but it comes out fairly easily. I was amazed at how light it was (and I'm a pretty wimpy guy :-). The trailing arms surprise me with their weight as well.

Gratuitous rear suspension shot.

Replace Bushings

There were many different ways documented on Dale's site and others, on how to remove the bushings. I pretty much used Mark Fiumara's plan with a few differences because of the tools I already had and the parts that were available. First I lit a propane torch and heated up the metal around the bushing. I heated it until my garage smelled like somebody lighting up their tires at the start of a drag race. Then I took two large flatblade screwdriver and wedged them in-between the bushing and the subframe. Pry down as far as you can to get the bushing started. Then I took a 6'' puller and put one side on the subframe at the section where the bushing is indented a bit (this way the puller doesn't catch on the bushing), and the other side on the joint between the top and bottom of the subframe. I was a little concerned about damaging the metal, but the amount of force it took to press the bushing out was faily low so no damage was done.

To put the new bushing back in I took 2 2.5'' PVC pipe caps and drilled a 1/2'' hole in the center of them. If you can find a 2.5'' and a 2'' steel pipe cap like Mark recommends it would work much better, but I couldn't find any. Anyway, then I jam-locked two nuts at the end of a 1/2'' threaded rod, put a washer over the nuts and put one of the pipe caps face up over the nuts (That's the larger cap on the top, in the picture). Then I took the rod and ran it down the center of the subframe and through the center of the bushing. I put the other pipe cap on the bottom of the bushing with the rod through the center of it. I put another washer on the bottom of it followed by a nut. Then I just simply held the nuts at one end of the rod with a wrench and tightened the lower nut. This will squeeze the bushing into place. Oh, one other thing, before tightening, I liberally sprayed the bushing and subframe with lithium grease. Now as you can see by the picture the bushing is longer than the subframe so I hit a point where the bushing hit the pipe cap (this picture was taken after the bushing was already completely seated). If the upper cap were a 2'' pipe cap (what Mark recommends) it would be especially handy, because you could reverse it so it was pointing down and the bushing would fit inside it.

Since I could only press the bushing in part way using the procedure above, I had to finish it off with a puller. "Why didn't I use a puller to start with?" you ask. Well, because the puller wasn't long enough to fit the bushing and subframe.

This picture is upside down with respect to the previous one

I also replaced the trailing arm bushings. They were a little easier to do. I heated the trailing arm again just like the subframe. Then I simply used a 3'' puller with a washer to press the old ones out. I also had to cut part of the bushing that sticks out so the puller could grab onto the trailing arm. Otherwise it would just grab onto the bushing itself.

Geez, somebody needs to teach this guy how to focus

Pressing the bushing it was easy as well. I sprayed liberally with lithium grease again and used a 6in puller to press the new one in. The hooks on the 6'' puller were a little large and the bushing ran into them, so I just finished off with a 3in puller when the bushing got that far in.

David Boyd