Replacing E28 Lower Control Arms
Replacing E28 Lower Control Arms
by Steven Jay Bernstein, BMWCCA #83901
I attended a Driver's School at
New Hampshire International Speedway in October 1994.
With a high mileage car, I underestimated the actual costs of the school. While the $90 entrance fee was
reasonable for anyone considering attending, one must not
forget to consider the
preparatory costs as well as the costs of repairing
damage. The obvious
lemma is that the more time/money invested prior to school, the less
time/money required after school.
I broke this rule. After not replacing the original lower
control arms (containing lower ball joints and lower control arm bushings)
with 227k miles on them, I blew apart a wheel bearing. So, instead of spending a gorgeous
weekend in the mountains after the school ended,
I found myself repairing my broken car.
The E28 front bearings are expensive to buy, but they do last
about 200k miles. They're even
more expensive when your car has ABS (my 1983 doesn't).
I limped home and spent the better part of Saturday searching for a new
wheel bearing, and Sunday in the Zen Buddhist exercise of conquering the
Having suffered some pain, and learned a bit, here is the definitive
procedure. If you have reasonable mechanical competence, this is surely a
do-it-yourself job. I can add this one to the list of "why did I ever
consider paying someone to do this??" jobs.
NOTE: This work was done with the rear
wheels on ramps, and the front
wheels on jack stands (with the floor jack remaining in place... just in
case). A lift indeed isn't required, although it would have made the job
a bit easier.
- Conquer the thru-bolt at the bushing. If yours is rusty, replace it.
It's an M12 x 1.5 pitch x 77mm long. Loosen the bolt, although don't
remove it yet. Leaving it in place makes it easier to loosen and to
remove the ball joint.
- Without removing the brakes (unless you are an idiot like me and blew your
wheel bearing, too 8^)), remove the 3 17mm bolts at the bottom of the
strut tower. This will allow you to access the locking nut holding on the
ball joint. It will also allow you to twist around the strut tower to
give you adequate access to this nut. This was not intuitively obvious to
me, and it ended up being very helpful once I figured it out.
- The original nut is the typical cotter-pin style that was made in the
early 80's. The new one has the plastic insert. While the ball joint
is still pressed in place, a 22mm socket on a 1/2-inch drive breaker bar
or torque wrench works quite well. An offset box-end was recommended,
but I found it to be unworkable.
- Once this nut is removed, the difficult work of removing the ball joint
begins. On the driver's side, with a judicious amount of Rost-Off (liquid
wrench to you yanks), a ball joint fork, the heat of a mapp gas torch (with
a wet sock protecting the thrust arm joint's boot), and a large hammer
applied strategically to one end of the lower control arm, it popped out.
If you have to apply excessive force, you should support the bottom of this
assembly since it isn't being supported by the strut tower (with those three
bolts removed). I used my old wimpier floor jack to counter the forces of
the blows on the lower control arm. On the passenger side, I cursed in
three languages! 8^) But seriously, this one was
a humdinger. The trick was to put the nut on the top of the ball joint so
that it is held on by maybe a few threads. Then, put back those three bolts
holding the assembly to the strut tower. They won't go in fully, because
this nut will hit against the bottom of the strut tower. This is the
key - I found that if you tighten these down, the strut tower presses the
ball joint right out of the socket!!! Simplicity itself.
- Installation is the reverse of removal. Get your torque specs from your
favorite manual. And follow Don E's advice about tightening the thru
bolts with the car on the ground and you'll be all set.
One side note: If you ever need to replace a wheel bearing, don't panic,
as I did, if the inner race pops out of the new wheel bearing before you
tap it onto the spindle. The solution to reinserting it is the following,
thanks to our friend, Roland Freund:
Remove the rear seal. Then remove the bearings, carefully, in its cage.
Then slide the bearings around the race and reinsert it. Reinsert the
seal, evenly. Fortunately, if the outer race comes out, you can insert
it by simply placing it in the hub at an angle, and it slips in place.
Also, another hint: To tap the new hub/bearing assembly onto the spindle,
*don't* hit the hub or the outer race will surely pop out. Take the
1-13/16 (or 46mm) socket that you used to get the nut off, place it over
the outer race, and tap away.
Thanks to Roland Freund for his technical advice, Jim Conforti for his
moral support and male bonding (he usually torques electrons and
passengers 8^)), and Charles Karnati for the 1-13/16 socket and the
©1997 - Steven J. Bernstein All rights reserved.
Steve's Home Page
Steven Jay Bernstein
P. O. Box 11242
Hauppauge, NY 11788 USA
Saturday, July 19, 1997