Touring Brothers,
No rain today, so I took a vacation day to replace the Rear Suspension Subframe Bushings on my 1999 540i Tour.
These Subframe Bushings are the connection point between the Rear Suspension Subframe and the bottom of the Tours undercarriage. The Rear Suspension Subframe contains the shocks, air springs, differencial, axle, rear control arms, wheel hub, brakes and wheels. You know, important stuff. All fastened to the body with these four Subframe Bushings.
These bushings are a common failure point for E39 Tourings. I had read various posts that these Subframe Bushings start to fail around 80-100k miles. The E39 Sedans don't seem to have this same problem. My non-sport 540it has 81k miles on it. Upon a brief inspection during my rear shock replacement, I found the two front subframe bushings on the rear suspension subframe had developed cracks in them and that was enough for me to decide to replace all 4 of them.
In previous DIYs, I had replaced the rear shocks and front suspension components. I have been seeking to renew my overall suspension from a soft, loose, questionable ride to a firmer, tighter, quieter, confidence building, awesome daily driving experience. This DIY is one in a sequence of DIYs to renew my Ultimate Driving Touring Machine.
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Preperation: Tools and Consumables
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For this DIY, here's most of the tools and consumables I used:
Not pictured are 4 wheel chocks, a floor jack, clean shop rags, 1/2" ratchet, 1/2" Torque Wrench, 2" long 1/2" inch socket extension and deep 21, 22 and 24mm sockets. I also printed off a copy of the DIY instructions as reference while I was performing the task. The Bentley manual was not much use for this DIY.
I also did not have to use the Brake Cleaner in the picture for this DIY, although in different posts, it was recommended to have it handy, just in case...
I purchased the Subframe Bushings from EAC Tuning for $107 shipped each. Took about two weeks for delivery from the dealer.
The key to getting this job done is the Subframe Bushing removal tool. I was lucky enough to rent one from jase007.
The rental kit jase007 rents out includes: The Franklin bushing tool with DIY instructions, tool description/instructions, four subframe extension rods and nuts, Moly grease and rubber bushing emulsion fluid. Contact jase007 if you have a future need for the tool, as there is a waiting list. I waited about four weeks between contacting jase007 and receiving the tool.
I won't duplicate the instructions that come with the tool, as there's not enough room for one post, but will show the main points in the process. Jase007's instructions are well written and easy to follow.
This DIY took me 5 hours. I suspect the next install we do tomorrow will go much faster, as I took my time and stopped to take photos along the way today.
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Part I: Lowering the Rear Subframe
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First thing was to loosen the wheel lugs on the back wheels, chock both sides of the front wheels, and jack the rear end up and get the Tour up on stands.
Once the car was up and the back wheels removed, I sprayed PB Blaster into the top seam of all four bushings.
I also sprayed the rear suspension self leveling sensor connectors with WD-40. While letting the PB blaster and WD-40 soak in, I collected the needed tools and consumables.
I then disconnected the electrical connector from each of the self leveling sensors. The passenger side sensor wire was difficult to just get the clip off. I used a 10mm ratcheting open end to remove the one retaining nut to remove the sensor from it's mount, then was able to unclip the sensor. I reinstalled the sensor without it's sensor wire as I didn't want it hanging around and potentially get damaged while the rear subframe was being raised and lowered.
Next, I marked the old bushings with painted reference marks at the two points where the subframe arm that holds the bushing attach to the subframe bushing frame. I copied the reference marks to the new bushings later on during the bushing installation process. The importance of this mark is to line up the new bushing properly on a forward/aft orientation during reinstallation.
I then used a floor jack to lift up the rear subframe against the body. I used the differencial case as the lifting point with a jackpad on my jack.
Do not position the jack on the seam between the case and the case cover. Only use the diif case itself. Don't lift the car off the jack stands.
I uncliped the wheelwell clips that attached to the subframe bushing bottom retaining plate.
Next, I used a 25" 1/2" breaker bar with a 21mm socket to loosen, but not remove, all four subframe bushing attachment bolts.
The next step, is to replace the bushing retaining bolts with a extension rod and nut combo that is longer then the attachment bolt. 4 rods will be placed in place of the original attachment bolts. The longer length rod will permit the suspension subframe to be lowered 2.5" to permit the bushing tool to have enough room to operate.
When placing the extension rods in place, they must be screwed in only hand tight about 2". I used the original subframe bottom plate with the extension rods. I placed the bottom bushing retaining plate on the rod, followed by one of the kit supplied nuts.
The front and rear bushing bottom retaining plates are different. The ones for the rear have a rubber pad on the bushing side of the plate. The front plates have no pad.
Leave the retaining plate and nut about 2 1/2 inches lower than the bottom of the bushing. When all four are in place, SLOWLY lower the height of the floorjack to lower the subframe on to the extended rods. I needed 2" of clearance for the bushing caps that go on top of the actual bushing for removal or subframe bushing retaining ring for reinstallation.
Prep is done. Now on to removing the first bushing...
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Part II: Removing the Subframe Bushings
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As part of the kit, there are both jase007's instructions as well as the use instructions from Frankin Tool company.
The main thing in both the removal and replacment of the bushings is to keep the main shaft both clean and well greased. This will keep friction low, generated heat down and preserve the tool itself. Because of the pressure involved in removing the bushing, power or air tools cannot be used to operate the tool as they will damage the tool. Only hand wrenchs or ratchets can be used. Clean the main shft before your first use and check it before every subsuquent use.
Place the small bushing removal bearing cap on the top of the old subframe bushing. Thread the main shaft of the tool through the bearing and screw it into the top cap bearing. In this shot, you can see why you need the 2" of clearance. Now is a good time to grease the main shaft using the Moly grease included in the kit.
There are a pair of collets that fit into indentations on the bottom of the old bushings. Then the main body of the bushing receiver goes over them, followed by the ball bearing and nut assembly.
Once the removal sleeve and ball bearing/nut is assembled on the bushing tool, it's time to crank the bottom nut on the tool. I used a deep socket 24mm with a 1/2 ratchet to crank the nut. While cranking, you will hear tearing sounds as the previous emulsion tears away from the subframe assembly. About halfway through the removal, I sprayed the top of the bearing seam with WD-40 to help the bearing slide through. When the deep socket will no longer work, due to the shaft pushing it out, use a 24mm box or open end wrench to complete the removal.
When the bearing reached the bottom of the receiver, I rocked the tool from side to side to remove the last portion of the bearing. This pic shows the tool with the bearing within. Disassemble the tool to remove the bearing.
The first bearing is now out. The next step is to prepare and install the new subframe bushing.
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Part III: Subframe Bushing Installation
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Installing the Subframe Bushings uses two other caps, the main shaft and the ball bearing/nut assembly to press the bushing into place.
First, clean the inside of the subframe bushing frame. Since I used PB Blaster and WD-40 to loosen the bushing, it actually cleaned the inside of the subframe bushing receiver. I just had to wipe it clean. Here's a view looking from the bottom of the Subframe Bushing receiver ring, up to the bottom of the body connection point up before I wiped the ring out.
Transfer the reference marks from the old bushing to the new bushing. Again, the importance of this is to line up the new bushing properly on a forward/aft orientation. There are a pair of arrows on the top of the bushing to orient as well, but they cant be seen during installation, hence the suggested markings on the new bushings.
Place the bushing tool cap with the notch in it. The notch aligns and locks into a ridge on the Subframe Bushing mount.
Check, clean and grease the main shaft. Thread the main shaft up from the bottom and loosley hand tighten. Use the included rubber emulsion liquid on the upper part of the bushing. The emulsion lubricates the bushing for reinstalling then dries to secure help secure the bushing in-place.
Position the new subframe bushing followed by the end cap and ball bearing/Nut assembly. The end cap has two raised tabs on it that fit in the bottom of the new bushing. Align the painted reference marks on the bushing to the subframe arm reference points per the Tool instructions.
Tighten the 24mm nut with a 24mm deep socket, followed by a 24mm box end wrench when the socket is no longer deep enough. Tighten until the bushing is snug, but not overly tight.
The painted reference marks I made should line up with the end of the arm that is welded to the bushing retaining ring.
Once the new bushing is in-place, replace the extended rod, bottom retaining plate and nuts and repeat the removal and installation process to the other three bushings.
*** Just a note, on the 540it, the rear drivers side Subframe Bushing mount won't lower as low as the other mounts due to the exhaust system in the way. There should be just enough room to lever the mount down to slip the top caps in-place. I used a 24mm open end wrench as a lever and got the required clearance with little effort or strain. For Dinan E39's installation, he had to remove the Dinan exhaust from it's rear mount to permit the required clearance for his modified exhaust.
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Part IV: Completing the DIY
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When all bushings are replaced and all extension rods are in-place, use the floor jack to again raise the suspension subframe back up to the body. Be sure you only raise the rear suspension subframe and not the car off the stands.
*** On the second tour we did, we had to help align the rear subframe assembly back up to meet the body attachment points by jiggeling the rear suspension so it would travel up the rods. We also moved the jack pad further back towards the end of the differencial case to push the rear of the rear suspension up. Do not position the jack on the seam between the case and the case cover. Expensive damage may occur to the cover on improper positioning.
Once up, replace the extension rods, one by one with the original attachment bolt and lower retaining plate. Be sure to put the lower bushing retaining plates with the rubber pads on the rear bushings.
Once all are original attachment bolts are reinstalled, check again to ensure the car is solid on the jack stands before tightening the bolts. Torque the attachment bolts to 120 ft/lbs.
Reattach the self leveling connections back onto the sensors.
Reattach the wheelwell clips to the bushing lower plate.
Remount the wheels and torque them to 80 ft/lbs. It was a good time to clean the inside of the style 5's again while they were off the Tour.
The emulsion liquid on the bushings needs 3-4 hours to set. Jase007 recommended to let it set overnight, so I'll test drive it tomorrow morning. Good time to clean the underbody.
Tomorrow, I'll take the Tour for a short spin before we work on the next Tour. It will be interesting to see what type of handling and ride change it will make.
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Part V: Observations and comments
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So, all four of my subframe bushings were cracked and empty of fluid. The front two were cracked both top and bottom and the rear bushings were cracked in the bottom. My 540it only had 81k miles. (New bushing on left, one of the busted ones on the right)
Mileage seems to be indifferent as far as bushing damage. My bushings at 81k miles looked as bad (or worse) than Dinan E39s at 120k+. I wonder if they actually fail closer to 60k miles than 80k.
On my test drive, I notice swifter response to throttle pedal inputs. I mean, it feels like the rear end of the Tour is sticking so much better than before with no hesitation. We reasoned that when the bearings wear out, on accelleration, it would allow the rear suspension to pivot for the travel of the damaged bushing before the the body set. Definately a more solid feel and setting up for a turn no longer has a hesitation or shifting feel to it. The rear end definately feels more planted. I didn't have any noise associated with the bushings. Dinan E39 did have some body ratteling noise which was eliminated with this fix.
For me, it is a noticable improvement, similar to the experience of replacing my rear shocks a few weeks ago.
Update: It poured rain today, it was a DSC kind of day. I had a 45 mile sprint each way to take care of a chore. The Tour was much more planted and stable through both legs. On the return trip, I followed some wet twisties home and the Tour's stability was definately noticible. The Tour is more neutral. stable and set in it's path.
This was not a difficult DIY at all, thanks to the really cool bushing tool and great instructions by jase007. He's got the better DIY.
My install by myself took 5 hours. Dinan E39, Mike and I knocked his off in 2.5 hours. I encourage anyone who has the knocking or loosness in their Tour to take this DIY on.
Brake system overhaul next... Cheers!
Member
Originally Posted by pjamesturner
AFT47 Touring Rear suspension bushing removal tool available
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