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Thursday, March 13, 2014

Tightening Control Arm Fasteners

Subject: Tightening Control Arm Fasteners
Vehicle Involved: All Vehicles

Condition: Preventing premature bushing wear

Repair Procedure: When installing control arms back on the vehicle after control arm, bushing, or ball joint service, it is important that the fasteners be tightened with the weight of the vehicle on the suspension so the control arms are at ride height.

Control arm bushings are constructed of a steel inner sleeve, a steel outer sleeve (in most cases), and a flexible synthetic rubber or polymer material in between which is bonded to the steel components.  When installed, movement of the suspension is achieved through the flexing of this material.  Being bonded to the steel, it has a limited range of movement.

If the fasteners are torqued with the wheels hanging – like when the vehicle is on a frame-contact hoist, jack or jack stands - returning the vehicle to a loaded position will place the flexible material in torsional tension.  In use, movement of the suspension increases this tension and premature failure will result.

1 comment:

  1. Lorenzo John5/21/2014 5:57 AM

    Thanks for sharing the article.You have properly explained the procedure of replacing the control arms.I used to find it difficult while doing my BMW Control Arm & Suspension Bushings but after reading this article, I tried and I was able to do it properly.