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Rear Suspension Rebuild - my experience - pictures - very long
Compliments of kbsilver @ bimmerfest.com
This write-up is my experience and what was learned from a near total rebuild of the rear suspension of an E39.
It is not a complete DYI, just what I experienced and learned along the way. Perform any of the described procedures at your own risk. It will hopefully be helpful to anyone contemplating a E39 Rear Suspension Rebuild. Pictures included for clarity and explanation purposes. All component terminology is indicated in the 1st picture below. Just about every component in the picture was replaced except for the swing arm, wheel bearing carrier, and the bolts. Also changed were the sway bar end links not shown in the drawing. The only wearable parts not replaced were the 2 inner bushings of the swing arm. But have never read of anyone needing these replaced.
Background – 2000 540iT with 100K miles. Dealer indicated one Upper Rear control arm (wishbone) was bad as well as both sway bar end links. Price was $650 parts and labor to change these 3 parts (did not include alignment). I decided to just do everything, as it was only a matter of time before other parts would need replacing, requiring an alignment each time. According to these boards I was overdue for the rear swing arm ball joints. Ordering from a few of the common on-line locations I was able to get all the parts for $620, delivered.
While this is a Touring, except for the air spring, and location of the shock, is exactly the same as a sedan. Actually the air spring makes it easier because you can just bleed off the pressure allowing for easy movement of the parts and eliminating many of the forces you would normally have to fight to change the ball joint. This is a good write-up for changing the ball joint, which describes in detail this process: http://www.beisansystems.com/procedu..._procedure.htm
I did purchase a few tools, most importantly the rear ball joint tool. After reading all the problems others had trying to use an improvise tool, thought would get the right one. It’s not a real BMW tool, made in China, but is of excellent quality, and most importantly worked very well. Am considering making a rental tool package for others doing this job.
Down to business - what I experienced and learned:
The right tools make a world of difference. The wrong tools will slow you down, a lot.
16MM and 18MM tools were very commonly used. A ratcheting 16MM open end/box wrench would be very helpful (I should have bought one). 5/8" works in place of 16MM.
I needed to also purchase a 24MM socket for the nut on the swing arm/ball-joint assembly.
All new self locking nuts were included with the new parts, EXCEPT the nut the above for on the swing arm. Purchased new ones from the dealer. This nut required 190 ft/lbs of torque, my wrench only goes to 150. Used the borrow a tool program from AutoZone for a larger torque wrench.
All the parts purchased (except one) were Lemforder brand. This is the OEM supplier. (There are some very cheap parts available but with the amount of labor involved, was not willing to chance it). On the Lemforder castings something was ground off each of them (can be seen in the picture). On the parts I took off the car, it’s the BMW roundel in that spot (obviously they do not have separate BMW/aftermarket castings). This was my confirmation these truly were the OEM parts. The integral link was febi (all that was available).
Clearance is very tight for much of the hardware. In some cases impossible to use a torque wrench.
Was all set to just use my impact wrench and speed off all those rusted bolts. Forget it, not enough room to fit on any of the bolts (except to take the tire off).
Had my front-end tool kit out expecting to have to use a tie-rod/ball joint puller to get the wishbone and traction strut off. Nope, they fall right out once the nut has been removed.
I needed to remove the shocks to get clearance for some of the hardware. May not be required on a sedan. If it’s in the way, remove it. Much quicker to remove the shock than fight it being in the way.
The single most difficult part (for me) was getting the bottom nut off the sway bar link where it attaches to the swing arm. Same for both sides. No clearance.
The second most difficult part was trying to get the new lock ring back on the ball joint. After realizing the best I was going to do was gash my fingers, purchased a lock ring (not snap ring which is different) pliers which solved the problem.
The old lock rings become rusted to the ball-joint and takes a few minutes to get off (you will destroy them in the process).
With the ball-joint tool it really only took about a minute to remove, and another minute to install the new ones. Amazing what the right tools will do.
First side took about 6 hours (including a run to purchase the lock ring pliers), second side took about 3 hours so plan accordingly.
In the end the only really worn part was the single wishbone. Boot was cracked, lots of play in it. The other side looked like cracking was not far away. Most other parts did not look that bad (including the sway bar end links I was told were bad by the dealer). The touring with air springs is very stiff and does not use a lot of the suspension travel. This may explain why many of the parts last longer than on the sedan. Replacing the integral link was probably not necessary, does not look like it would ever wear out.
More or less the steps:
With a full tank of gas (any maybe a driver), measure the distance from the center of each rear wheel to the lip of the quarter panel. You will need this measurement later.
Jack car, secure on jackstands, remove tires
Disconnect the height level sensor(s). If you have Xenon’s or air suspension, you have these sensors. They are easily broken thus should be the first thing disconnected, last thing reconnected.
Mark the position of the eccentric bolt/washer on the traction strut (part #1). You will want this in the same position when you are done to keep alignment reasonable.
Spray penetrating oil on all the parts you will be unscrewing
Loosen/Break free all the bolts. Be sure to loosen the big nut on the swing arm before deflating the air springs (if applicable, lots of torque required, you need the spring force to hold things in place)
Remove the ABS sensor/Brake wear sensor from the clips and remove the plastic wire holding fixture from the wishbone.
Remove the shock if needed.
Remove upper sway bar end link bolt (16mm socket). Use a 17mm open-end wrench to stop the shaft from spinning
Remove, install new wishbone. Do not tighten fully until the end. You need to use 2 wrenches on the part that attaches to the wheel bearing carrier. One to turn the nut, one to hold the shaft from spinning, see pictures.
Remove, install new traction strut, There is a mating eccentric washer under the nut, do not loose this, note how it came off for reassembly, Again do not fully tighten until the end. Same deal as the wishbone, 2 wrenches are needed for the part attaching to the wheel bearing carrier.
Remove the big bolt in the swing arm/ball-joint assembly. You need to get to get the forces off this bolt to be able to get it out (see Beisan systems link). If you have air springs, now’s the time to bleed it down.
Remove the other bolt in the integral link
Note you should never pry against the half shafts.
Jack up the carrier to separate from swing arm to get access to ball joint.
Remove the integral link
At this point you have maximum access for that nut on the lower part of the sway bar end link (the #1 most difficult item for me). This is the optimal time to change it. (There is a single washer that is used only on the lower joint, where it attaches to the swing arm).
Spray penetrating oil on the ball joint lock ring. Remove lock ring (you will probably destroy it)
Remove ball joint using special tool. Remember to use grease to lubricate the screw. Reapply grease for every use.
Use very fine emery paper (600+) and clean up the front and rear face surfaces of the ring where the ball joint goes (not the inner bore). Finish off with by cleaning well (brake cleaner works).
Use tool to install new ball joint (I found out it was possible to use the tool backwards during the install in which case it goes about 80% of the way and then it gets stuck. No harm, after panicking, turned tool around and finished with no problem).
Install lock new lock ring (again lock ring pliers recommended)
Install integral link (new or old). Re align sections and install the big bolt and use a new locknut. The sections need to be aligned well or else you will not get the bolt in. Wait until next step for final tightening.
Reinstall shock if removed
You are suppose to tighten everything with the car on the ground, suspension settled, full tank of gas, driver, etc. Unless you have an alignment lift at your disposal, this is impossible to do. Instead….
Jack up the assembly until the distance is the same as the car on the ground (measurement you took before). If with regular springs you may end up lifting the car off the jackstands. With air springs, cake.
With the suspension in the ‘normal position, now tighten/torque everything. You need to do it this way else you will put strain on the rubber bushings in all the components, possibly even tearing them just driving to get the car aligned if this process is not followed.
Connect/Install upper nut in the sway bar end link.
Install the cable harness on the wishbone and snap in cables
Re attach level sensor.
If you have air suspension, do not drop completely to the ground after removing jackstands or you may damage the air bags. Lower to about 1 inch lower than normal height, holding at this position with the jack. Turn the ignition on and allow the air system to pump up the air springs and the car should lift itself off the jack.
Have the car professionally aligned (4-wheel).
If anyone is interested in renting a tools for doing the ball-joints let me know. If enough interest will make up a kit of the ball-joint tool, lock-ring pliers, 1-1/8" socket for the tool, 24MM socket for the swing arm nut. Something along the line of $30 including shipping. (Would probably work it by asking for $130 via paypal, returning $100 when the kit is returned in good condition, 2 week rental time).
Parts Schematic Drawing
All the new Parts
Disconnected Height Sensor and traction strut eccentric washer marked
Using 2 wrenches to remove/install bolt on wishbone and traction strut
Jacking up to prepare to remove ball joint
Tool configured for ball joint removal
Tool configured for ball joint install
Nice New Parts
All the old parts
Tools purchased for Project (would be the ‘kit’) The 4 shells (2 have bearings inside) for the ball joint removal/install with the threaded high strength bolt and special nut, 1-1/16 socket, lock ring pliers, 24MM socket.
FCP Groton (a reseller not a manufacturer) does not use OEM Lemforder parts. They use some of those less expensive parts I was talking about (Karlyn is one brand). For me saving a few $100 is not worth it given the time involved. I ordered the parts from 3 different on-line suppliers to get the best price. In most cases Lemforder was the most expensive option (but not always). I expect to never work on the rear suspension again (on this car).
Minor update. Took the car in for an alignment, and it did need it, most adjustments (as expected) in the rear were out. Interestingly enough, it rides noticeably smoother. While none of the parts appeared to be worn enough to make a difference, guess it's just the sum of the parts. With the original parts (and the touring air springs), the rear suspension was near bone jarring on anything but smooth contiguous pavement. Now with the FSD shocks and all new rear suspension parts, ride is not too bad. Handling was never a problem, always excellent.
The vendor I orignally used (as recommended by Jason5driver) no longer has the ball joint removal tool listed, alternate is below (same tool, more expensive). However as most people only need this once, am willing to rent mine as a kit with everything else I purchased around the removal and installation of the ball joint. Just PM me if interested.
http://cgi.ebay.com/ebaymotors/BMW-REAR-ALXE-BUSHING-REAMOVER-INSTALLER-TOOL-1115_W0QQcmdZViewItemQQ_trksidZp1742Q2em153Q2el126 2QQcategoryZ35625QQihZ007QQitemZ170129733217QQtcZp hoto
Some corrections for Jasons instructions above:
Breaker bar + Pipe for leverage (needed for that 24mm nut)
It's a lock ring pilers (which is different than a snap ring which has little holes in it)
My wife was not willing to help (and it's HER car!)