E30 & E36 BALL JOINT FAILURE Issue date: 4/02
This is an update to Tech Bulletin 02-97. Similar failures have been reported on E36 vehicles. This bulletin is extended to include E36’s.
Investigation into several Club Racing/Drivers School incidents during the 1997 season have revealed total failure of the Ball Joint Stud on the Lower Control Arm resulting in immediate loss of steering.
We recommend the following preventive measures (until otherwise noted):
1. When preparing an E30/E36 for club racing, start with new control arms.
2. Replace all steel control arms after 2 seasons of use or 20 events.
3. Replace all aluminum control arms after 2 seasons
4. Replace control arm if a ball joint has any amount of “up and down” play when squeezed with a large “water pump” pliers.
5. Replace control arm if a ball joint has any “side to side” play in it when grasping the outside of tire and shaking from side to side or up and down.
6. Do not re-use poly lock nuts
7. Torque ball joint stud nuts to spec!!
8. Re-torque nut several times during season. It shouldn’t turn–if it does, investigate why.
9. If an “incident” involving enough force to bend a road wheel occurs–replace control arm.
10. When trailering a car, do not tie car down around or thru control arms.
11. Use quality replacement parts. BMW original or Lemforder brand are the only ones we recommend. There are inferior quality control arms being sold by large, well known suppliers.
12. It is important to understand that the type of failure we have seen may be undetectable by in car physical inspection. Change the arms at the time and usage specifications listed above, not just with normal ball joint wear inspection.
Inspect the subframe tapered socket and area around the socket for cracks and elongation–use a mirror to see the upper portion (especially on the right side of car–we have seen many cars that crack in this area). This may cause ball joint failure.
PART NUMBERS FOR E30 LOWER CONTROL ARMS
Aluminum 31 12 1 130 823 left $244.00
31 12 1 130 824 right $244.00
Steel 31 12 1 127 725 left $115.00
31 12 1 127 726 right $115.00
Outer–control arm to spring strut with new poly stop nut 47 ft lbs, 65 nm
Inner–control arm to front axle carrier 61 ft lbs, 85 nm
To show that “hand or wrench tight” is not appropriate–here are a few more torque specs(notice the big difference in ft lbs)
Brake bleeder valves–all 7mm wrench size 3.5 ft lbs
Brake bleeder valves–all 9mm wrench size 4.3 ft lbs
Front wheel hub collar nut E28,E24,E30 M3 210 ft lbs
BMW has a handy pocket sized torque spec book available:
Supplement 13– part # 01619783691 $12.75
Binder– part # 01699099704 $ 5.59
Registers divider–part # 01699099705 $ 2.40
Remember that safety is always our first concern. Please take special notice to this bulletin and remember that your car should have a thorough tech inspection before every event. Drive safely and we’ll see you at the track!!!!!