The government mandated that the car manufacturers design vehicles that will protect the vehicle’s occupants in front collisions. Vehicle makers have responded by building cars that will absorb a great amounts of energy in frontal impact and along with frontal air bags, the contributes to much less injury and death. Look at the above picture and you will notice that front structure collapsed nearly 50 percent of its original length, but the passenger compartment hardly had any deformation. This was all accomplished by using high strength steels, internal reinforcements, crush zones and laser welding (Example-The front rail on a Toyota Camry has 3 different thicknesses of metals attached using laser welds). The Federal Government started to look at side impacts and rollovers more seriously in the mid 90’s. Our first encounter in the body shop was door intrusion beam. These parts were constructed of ultra high strength steels. The insurance institute of highway safety as part of their crash ratings began to test for rolls over and side impacts.
IIHS devised a test by placing a weight on the “B” pillar and measured the amount of crush.
The standard of 2009 was 3 times the weight of the vehicle and in 2012 it will be 4 times the weight. To achieve a 5 star rating, vehicle manufactures began increasing the strength of the “B” pillar reinforcements. Toyota uses steel with a MPa rating of 590 and the Volvo XC 90 reinforcement rating is 1100Mpa. Let’s look at welding and the affect of heat on Advanced High Strength Steels (AHSS).
Looking at the above picture, you will notice the weld, silver metal and the black oval ring around the weld. The black oval ring is called the “heat affected zone” In I-CAR’s Damage Analysis 8, there is a demonstration on the affect heat on ultra high strength steel. The UHSS was changed to mild steel by heating the metal to 1200 degrees Fahrenheit. The temperature in the HAZ can reach up to 2000 degrees, which will weaken or destroy its ultra high strength properties. Realizing this fact will help understand
Why some manufacturers require that the entire reinforcement is replaced instead of sectioning the part. To better understand the drastic changes that started in 2009, I will demonstrate the start to finish process of a “B” pillar reinforcement in a 2009 Toyota Camry.
I contacted Joe Di Donato, the lead instructor at the Toyota University in Torrance, California about documenting the removal and replacement of a “B” pillar reinforcement. Joe, who I consider to be one of best instructors in the country, accepted the challenge (of baby sitting me for 3 full days). I printed out the repairs from Toyota’s Technical Information System (TIS) along with all pertinent Collision Repair Information Bulletins (CRIB).
1. Vehicle is placed on a frame bench
2. Vehicle is measured to determine the extent of damage
3. Upper body measurements are taken
4. Replacement outer panel is placed into position and marked.
5. The outer Roof panel and post cover is cut and saved. The welds on the inner “B” pillar reinforcement are exposed
6. Clean and expose all spot welds as outlined in TIS removal document. I started to remove some spots welds that did not need to be removed. I also missed a couple of spot welds on the bottom of rocker panel. Again, you need to look at removal document prior to beginning the repairs. I would suggest that you mark all spot welds on the car as well as the data sheet.
7. Mark the outer rocker at the sectioning location and cut.
8. Remove the entire piece as a single unit. Again I did not follow the instructions and tried to remove all the damaged parts separately. This took a lot more time.
9. Clean all the mating surfaces.
10. Apply weld thru prime to all bare mating surfaces.
11. Measure the thickness of the metal
12. Weld some scrap metal from the removal process and perform a destructive test. We welded a number of scrap pieces at different thickness settings. The welds looked good, but all failed the destructive test. We discovered that there was not enough amperage on the circuit that we were plugged into. We move the machine to a different plug (85amp circuit) and we were able to get a good weld that passed a destructive test.
13. Test fit the inner “B” panel reinforcement,
14. Weld inner “B” panel reinforcement to the out rocker reinforcement (We reused the old one, but I would recommend that you use a new outer rocker panel.
15. Weld upper portion of the “B” panel reinforcement to the roof panel.
16. Apply epoxy primer to all bare metal. We mixed up some epoxy primer in a cup and applied it with cotton applicator (outline in the TIS).
17. Weld the outer rocker panel reinforcement to the vehicle. Use only an open butt weld. Toyota does not recommend a butt weld with backer on any welded joints as per CRIB #176 (revised).
18. Set outer “B” panel reinforcement on vehicle and mark plug weld locations. Perform practice welds and conduct a destructive test prior to welding on the vehicle.
19. Measure as per dimension sheet in repair manual,
20. Weld outer “B” panel reinforcement with squeeze type resistance spot welds and MIG welds as outlined in the Toyota Repair Manual.
21. Apply weld thru primer to all mating surfaces.
22. Apply semi rigid foam as outline in the Toyota Repair Manual.
23. Weld in outer access panel.
24. Set outer “B” panel and rocker cover on vehicle a mark the cut location.
25. Cut panels using cut and join technique.
26. Weld outer panel with stitch method and STRSW.
27. Dress all welds.
28. Apply epoxy primer to bare metal
29. Apply body filler
I was visiting a local collision center and they had a 2010 Toyota Prius on a frame bench. The parts had arrived and the shop had both doors off. I asked the shop foreman what procedures he was going utilize in the process. He explained the tech was going to repair the inner “B” panel reinforcement (pulling with a frame tower). I went into TIS and pulled down all the repair information and CRIBs pertaining to this particular repair. CRIB #175 (revised) states “Because occupant safety is such a high priority, HSS & UHSS occupant cabin reinforcement repair is not recommended.” If goes on to say not to use hot or cold straightening methods. The original estimate now needed to be changed and additional parts ordered. This delay could have been avoided by printing out the necessary documentation for this repair at the time of writing the estimate. The easiest way to get this info is directly from the Toyota web site. Go to oem1stop.com and click on Toyota. You can subscribe for 2 days, 30 days or 1 year.
Here is another point from CRIB#175 revised. “Do not section 980 MPa and 590 MPa strength rated pillar reinforcements. Another reason why Toyota states that the “B” pillar reinforcement on a 2009 Corolla, Prius and Camry are replaced in their entirety. The Venza on the other hand has a laser weld near the bottom of the reinforcement, which separates the upper portion of 590 MPa steel and lower portion 440 MPa steel. The “B” pillar reinforcement can be sectioned using an open butt joint on the lower portion of the panel. I-CAR has just introduced a new class called TOY 01 and it is a must for repairing today’s Toyotas correctly. Another class that I would recommend for estimators, appraisers and body technicians is I-CAR’s POP 01. This class deals with the OEM’s recommended repairs for Toyotas, Hondas and Pontiac G8. Lastly, I would like to discuss the training program from Toyota.
Toyota University has a number of excellent classes. You can take a classes on refinishing (2 day hands on class), Color matching, Hybrids, Non-structural repairs (2 day class) and structural repairs (also 2 day class). I attended recently the Toyota structural class with Joe Di Donato. The first day we went over the theory of the Toyota Structural repairs and the second day we install a rail section in a Camry. The class uses the latest equipment and Joe is an excellent instructor (not as good as me, but real close—just kidding). The class in open to anyone. All you need is a SPIN number (get it from your local Toyota dealer) and sign up on line and that is it. The best thing of all is its cost. Dirt cheap for what you get. Hope that I was able to give a better insight into the repairs of Toyotas.