Steering, Suspension and Wheel Damage Explained


Did I scare all of you with a reminder of geometry?  Or even worse trigonometry?  Remember being in High School and thinking, “I am never using this crap so why do I need to learn it?”  Well look at who needs that stupid geometry and trig now.  What?  You don’t realize you need to understand these formulas for triangles, squares and areas?  Three-dimensional measuring, that we all should be using every day to diagnose and repair vehicles, is all based on geometry.  But, unlike structural dimensions, steering and suspension component measurements add the dreaded trigonometry formulas to obtain the degrees of measurements to align the steering geometry.  We are going to look at the operations to diagnose and determine steering and suspension misalignment.

Advancements in smart auto-adjusting suspension systems, steering assist and autonomous steering systems require new understanding. Without an understanding of these components, applied impact forces, and vehicle designs, as well as additional reading, research and training, damage assessors and technicians are having a difficult time diagnosing the sustained damage to these components. In many situations, damage to these components goes undiscovered until the vehicle goes in for a wheel alignment, or technicians attempt to replace components and then discover the parts will not fit. Both situations are generally near the completion of the repairs and will cause more unnecessary delays.  Another issue, unknown to many due to lack of training and education, is that many OEMs are requiring the replacement of rack and pinion steering units if a tie rod sustains damage.  Some OEMs require adjacent steering and suspension components be replaced if only one suspension component sustained damage.  It is paramount that a collision damaged vehicle be properly diagnosed by performing a thorough examination of the vehicle.  How do you examine the steering and suspension components to verify if there is sustained damage and/or displacement?  One way would be to perform a wheel alignment check, but this could be an issue if the steering and suspension mounting locations are damaged or displaced and/or the structure of the vehicle is displaced.  The first operation to perform is a vehicle system scan, or pre-repair diagnostic scan.  This test will scan the vehicle’s electronic systems for any faults and or issues, and should be performed on all vehicles entering your shop.  This test will determine any issues with the vehicle’s electronic systems and, if any are present, assist you in determining which system faults are related to the collision event.  The next operation would be to perform some quick checks on the vehicle’s structure and mechanical components (engine, cooling, steering and suspension, etc…).  Before we get to the importance of pre-repair three-dimensional measuring to diagnose steering and suspension components, we need to address the importance of knowing what occurred in the collision event – like a detective would analyze it.  You need to put the puzzle pieces together to get a full understanding of what applied collision impact forces caused the type of sustained damage during the event.  Next, check the OEM repair manuals for required inspections after a collision event, and then determine what quick checks to perform.

Diagnosing Damage

It is important to understand the description of the event and the type of collision the vehicle was involved in.  For example, a vehicle traveling at 15mph on snow that slides into a curb and causes scraping of the rim and bending of the outer tie rod is completely different than a vehicle traveling at 30mph and impacting a pot-hole that bends the rim and the outer tie rod.  Many OEMs are utilizing aluminum to make the suspension components which react in a different manner than their steel counterparts.  During a collision event, the applied impact forces can cause the aluminum components to bend, deform and be displaced – not only at the point of impact, but very often to suspension components in the opposite area of the impact.  Damage is frequently not visible to the naked eye and requires mechanical or electronic measurements to confirm or deny sustained damage.  Damage assessors and technicians must never assume that damage is or is not present; they must confirm it by measuring.  They must also check the OEM repair and diagnosing information on procedures after a collision event and position statements on wheels, steering and suspension components.

Wheel Assemblies

Wheel assemblies (tire, rim, valve, TPMS sensors) need to be evaluated for the extent of damage sustained.  Most of the OEMs have position statements that state “no bending, reshaping, adding material, removing material, welding or heating of the rim.” Therefore, refurbishing a wheel assembly should not be performed if any of the above repairs are necessary.  Generally, only sanding and buffing or sanding and refinishing are allowed.  The extent of sustained damage is often unknown, due to micro-cracking to the alloy, that may be present and undetectable without Magnafluxing the rim, which may be cost effective, or X-Raying the rim, which is typically not cost effective.  As mentioned above, what type of damage did the rim sustain?  Are there light abrasions (scuffing, scrapes, scratches aka “curb rash”) or is there significant abrasions (gouges, missing portions, deformities)?  Is the tire disabled and if so what is the root cause?  Is the tire sidewall scraped, gouged and or breached?  What is the condition of the tire?  These are all questions to ask yourself during the analysis.  Wheel runout and radius tests should be performed prior to removing a wheel assembly to examine the steering and suspension components.  The damage assessor must work in steps and understand how to confirm or deny which components sustained damage.

Steering and Suspension Components

Measuring suspension components can be done comparatively with mechanical devices, such as tram gauges (long measurements) and tape measures (short measurements) to determine displacement.  A speed square can also be utilized to take comparative measurements of components from an undamaged assembly to compare to the suspected damaged assembly components.  If components are found to be displaced or misaligned, then we recommend electronic three-dimensional measurements be taken of the structure of the vehicle, the mounting locations for the steering and suspension components and of the steering and suspension components themselves.  This can be performed with three-dimensional structural repair measurement equipment from manufacturers, such as Car-O-Liner (Vision X3 or Point X), Matrix Wand, or similar.  If wheel alignment equipment is available, and the structure is within specifications but one or more of the wheel assemblies show indications of displacements, we recommend a four-wheel alignment check be performed to determine which components are misaligned.  If a pre-repair wheel alignment check can be performed the technician can utilize the data to determine which components may have sustained damage.  Performing these procedures will ensure that the technician knows what requires replacement.

Many vehicles have multiple electronic assist components and electronic controls that must be initialized and re-set after component replacement or just disconnection and removal for repairs.  Systems, such as automatic cruise control, lane departure and accident avoidance systems work with the steering system, through an array of different type sensors that all communicate to computer modules that assist and or control the vehicle systems or even the vehicle itself.  Additionally, many vehicles have a backup camera and most of them work with or off the information provided by the steering angle and/or yaw-rate sensors or side view or rear-view mirror cameras.   These systems must also be checked during the analysis process, typically through a scanner through the Data Link Connector (DLC).  Some OEMs require sensors to be replaced in the area of damage, even if the sensor housing or lens show no visible sustained damaged.  Some OEMs require panels, deformed in the collision and normally repairable, to be replaced if these type sensors mount to the panel.

The Operations to Follow

Today’s damage assessors need to become para-engineers due to the changing complexity of vehicle designs and components.  This industry needs to raise the bar on education and training.  The general driving public is relying on us to ensure their vehicles are repaired safely.  Too often, we inspect vehicles post-repair or during accident reconstruction and discover incorrect repair procedures attempted or unrepaired damage, where they were a contributing factor in the subsequent collision event.  Many times, we find that wheel assemblies, steering and or suspension components failed in those investigations.  Failure of these components, that sustained damaged and undetected during the previous repairs, can have disastrous results, and all the liability rests solely on the repair facility.  Always follow the OEM repair procedures and protocols.  Making a business decision to appease a third party can expose you to a huge financial loss, if you were negligent.  Here is a general overview of some Operating Procedures you may want to adopt, after the vehicle is put into the blueprint/triage process:

  1. Wash the vehicle
  2. Install steering wheel cover, seat cover and floor mat
  3. Take photographs of the vehicle
  4. Mileage, any MILs, interior from both sides, Public V.I.N., V.I.N. label, registration, license plate, trim level identification, etc
  5. Overall four corners, front, rear, left and right sides
  6. Overall photographs of the damaged panel and or component, then two to three zoom-in photos of the damage
  7. Perform a Pre-Repair Diagnostic Scan, print the report (hard copy and PDF)
  8. Take some preliminary measurements utilizing quick checks, tram gauge, tape measure, gap gauge, etc… This includes the body panels, closure panel operation and wheel positions. If misalignment is uncovered the vehicle will require electronic three-dimensional measurements
  9. Check the body panels with a film Mil thickness gauge and record the readings
  10. Start disassembly of vehicle and categorize reusable components and components requiring replacement. Take photos of the process and any uncovered damaged components.  Wrap and protect all reusable components and store all components. Additionally, take notes on which OEM procedures must be obtained
  11. Prepare the vehicle for diagnostic electronic three-dimensional measurements print the report (hard copy and PDF)
  12. Recheck which components, bolt-on and weld-on including structural components will require replacement and which OEM Procedures to obtain
  13. Obtain all OEM procedures for the repair and print the report (hard copy and PDF)
  14. Prepare you damage report
  15. Check the damage report operations with the technician
  16. Send a replacement parts list order to the dealer for price and part number verification and any additionally required components and or hardware
  17. Make any adjustments on component prices, additional items and part numbers to your damage report

We hope this assists you in understanding how to check steering and suspension and wheel damage.  Look for more articles dealing with the blueprinting/triage process and the operations required to ensure a smooth hassle-free and efficient repair.