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BMW E39 Front Lower Control Arm Replacement
 
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Pelican Technical Article:

BMW E39 Front Lower Control Arm Replacement

Kerry Jonsson

Time:

4 hours4 hrs

Tab:

$200

Talent:

***

Tools:

22mm wrench, 16mm socket with ratchet or wrench, 18mm socket with ratchet or wrench

Applicable Models:

BMW 525i Sedan/Wagon (2001-03)
BMW 528i Sedan/Wagon (1997-00)
BMW 530i Sedan (2001-03)
BMW 540i Sedan/Wagon (1997-03)

Parts Required:

Lower control arm, fasteners

Hot Tip:

Loosen nuts as much as you can before removing joint

Performance Gain:

Tighter feel in corners, eliminate vibration and increase tire life

Complementary Modification:

Change radius arm bushing or whole arm.

BMW's reputation is built on performance, power, handling and reliability. BMW uses aluminum arms in most of their suspension systems and they offer strength and light weight. After many miles of harsh roads and spirited driving ball joints and bushing start to wear. Over time this can lead to vibrations, poor road feel and uneven tire wear. Rebuilding your front suspension can restore the handling, eliminate vibrations and extend tire life. The lower control arm is a sturdy piece of the puzzle but it does have an outer ball joint built into it so it gets replaced as a whole unit.

These fasteners are going to be tight and there is not a lot of room to swing the wrench. You are going to have to be patient and use some force to remove fasteners and components to rebuild your front end. Corrosion may hold a joint in even after you have loosened a fastener. Keep in mind the joint may pop out when you use a removal tool so keep your hands clear and wear protective gloves.

Lift and support front axle of the vehicle. See our tech article on jacking up and supporting your vehicle. You have to remove the front tires to perform this job.

The procedure to replace the lower control arm is the same for both the left and right side. In these pictures we will be alternating between the left and right side. We will note it in the caption just keep in mind the step applies to both sides. It is recommended you replace both sides at the same time to keep your handling neutral.

Replacing Front Lower Control Arm:
This is the front lower control arm (green arrow) that we are going to remove.
Figure 1

This is the front lower control arm (green arrow) that we are going to remove. The one pictured here is on the left side. Both arms have a bushing (yellow arrow) that mounts to the body and a ball joint (red arrow) that attaches to the spindle. There should be a warning label for tow truck drivers not to pull on these suspension arms with hooks for towing.

Here is a close up of the ball joint on the left side control arm attached to the spindle.
Figure 2

Here is a close up of the ball joint on the left side control arm attached to the spindle. Notice the cracks (green arrow) in the dust boot that protect the ball joint. This cracked boot will allow road salt, dirt and water to enter the ball joint and cause wear as the vehicle is driven.

Start by removing the inner bushing mounting fasteners.
Figure 3

Start by removing the inner bushing mounting fasteners. Once you have removed the nut push the bolt in the direction of the blue arrow to remove it.

Use an 18mm wrench or socket and ratchet to hold the nut (green arrow).
Figure 4

Use an 18mm wrench or socket and ratchet to hold the nut (green arrow). Use a 16mm wrench or socket and ratchet to loosen the mounting bolt (yellow arrow, hidden behind the subframe) and remove the bolt.

Spray the ball joint mounting nut (green arrow) with penetrating oil.
Figure 5

Spray the ball joint mounting nut (green arrow) with penetrating oil. This will make it easier to thread the nut off without loosening the ball socket

Thread the 22mm mounting nut (green arrow) off as far as you can.
Figure 6

Thread the 22mm mounting nut (green arrow) off as far as you can. It will not come out all the way because it will eventually hit the bottom of the strut. Avoid knocking the ball joint out of the spindle until you have the nut almost all the way off. If you only loosen the nut and the ball socket starts to come out of the spindle you will have a hard time threading the bolt off because the ball socket will just spin with the nut. If the ball socket does come loose you can remove the strut and use a 5mm Allen socket to hold the ball joint shaft still while you wrench off the 22mm mounting bolt. You can cut a 5mm Allen key short to fit under the strut and hold the ball joint shaft still while you wrench the 22mm mounting nut off if necessary.

Use a splitting fork to separate the lower control arm ball-joint from the spindle.
Figure 7

Use a splitting fork to separate the lower control arm ball-joint from the spindle. Be careful and use protective eyewear incase metal chips fly off as you strike the fork with the hammerÂ'. Installation is the reverse of the removal steps.


I find it easier to install the inner lower control arm bushing first, install the mounting bolt and tighten the nut a little. Then install the ball joint shaft through the mounting hole in the spindle. You are going to want to put some pressure on the ball joint so the shaft stays still or use your special shortened Allen key tool to hold the shaft still while your tighten the 22mm mounting nut. Once you have the outer ball joint tightened down go back and tighten the inner lower control arm bushing mount.

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Comments and Suggestions:
Tony Comments: The following is my experience on a 540i with only 175.000 kms, [about 109.000 miles], which may help anyone who, like me, may be faced with trying to separate the ball joint from the carrier, despite all the heavy hammering advice given on various sites.
The left hand side arm took only a few sharp blows with a hammer.
The right hand side refused to budge at all. A standard ball joint splitter was too small.
I purchased a pickle fork but that didn’t work either. By this time a number of hours had gone by and I needed to use a different approach. Continued heavy hammering was likely to do more damage than good.
Using a small Camping Gaz blowtorch I applied heat to the side of the carrier at the point where the ball joint enters the carrier.
After a few minutes the arm dropped free but it came away together with a liner, or sleeve inside the carrier which can be seen in the attached photo.

It didn’t seem possible to buy a new sleeve from the OEM parts site; it seems to be an integral part of the carrier, therefore it was necessary to separate the shaft from the sleeve.

I used a grinder to cut off the threaded shaft at one end and the ball joint with arm at the other end. I recommend using a diamond blade, as thin as possible, to avoid creating a burr where the cuts are made, which will obstruct the removal of the rest of the shaft.
I placed the shaft with the sleeve still attached on a workbench vice, applied a little heat, and hammered the shaft free.

The sleeve was put back into the carrier without any problem, a few gentle taps were required for the last few millimetres. The new arm was then installed as given in the description on this page.



November 5, 2017
  Followup from the Pelican Staff: Thanks for sharing your repair process and experience. These type of comments add so much to the Pelican tech community.
- Nick at Pelican Parts
 
Smoky540i Comments: Do you need to load the suspension with the vehicle's weight before torquing the bolts/nuts down?
June 23, 2017
  Followup from the Pelican Staff: Only on the control arm bushings. - Nick at Pelican Parts  
Christian Comments: when replacing the front upper and lower control armsBMW 540 E39, should you replace both the bolt and nut or just the nut at the bushing ends of the control arms.
April 28, 2017
  Followup from the Pelican Staff: usually just the self-locking nuts. BMW does suggest replacing both, but most folks don't. - Nick at Pelican Parts  
JDeGrafg Comments: I'm going to be doing all the arms under here except for the sway bar. Will I need to mess with the strut at all?
March 1, 2017
  Followup from the Pelican Staff: From memory, no. I think you will have enough space to loosen and detach the lower control arm from the wheel bearing carrier. The strut will actually hold the wheel bearing carrier and brake components for you while you perform the swap out. - Casey at Pelican Parts  
Nathan Comments: I replaced the Lowe control arms, they came with circs for lube but aren't ey already lubed new?
January 2, 2017
  Followup from the Pelican Staff: What vehicle? What brand parts? Can you share photos? - Nick at Pelican Parts  
Kai Comments: Does this job require an alignment afterward? What about after replacing the upper control arms?
May 26, 2016
  Followup from the Pelican Staff: It is suggested you have the alignment checked when replacing or removing any suspension components. - Nick at Pelican Parts  

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Page last updated: Sun 11/19/2017 02:05:35 AM