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Old 06-27-2003, 07:48 PM
trees trees is offline
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Ok, I have an up date since I have removed all the parts on the failed side. Tomorrow, I strip the other side. First, my dealings with Fat Mans Fabrications. I have been to their facility and will say they are a firsct class operation. They do have a design function and use prototypes and extensive testing. They also do structural analysis and Fatman himself is an engineer with lots of metalurgical background. I explained the problem to a technician, who looked up my record with the company and knew every thing I had purchased and when I purchased it. He proceded to tell me they had problems with some of these bolts in the past and my most recent kit had special 5/8 inch bolts built to made to their specifications so they could maintain quality control. They were going to send me all new bolts (5/8") , bushings, and ball joints, no charge, and that Fatman himself wanted to talk with me as soon as he could break away from some customers. He called me at the shop about an hour later and wanted all the details. He said this was the same type failure as 5 others and they had done metalurgical testing on them and determined they had received a bad batch of bolts that had not been properly heat treated. The part of the bolt close to the threaded end was softer than grade 5 and near the head and the fracture, it was closer to grade 8, which was indicative of flexing (working) hardness. Neither he not the technician tried to BS me and readily acknowledged a discovered weakness and had taken corrective action. He also offered to pickup the tow bill (did not have one) and will pay for the alingment when I provide him with the bill. After talking with him, I discovered the Carrera shock shaft is bent next to the eye and I'm sure there will be a new one here by the time I am ready for it. He did say this was the 6th 1/2 " bolt failure out of approximately 40,000 they have put in service, so their track record is really good. There is one thing I did not do on assembly that I should have done, and you can bet will be done in the future. I did not put any lubrication on the bolt because I did not consider it to be a wear item. This bolt is rusted in (the hole (Fatmans welds a thick wall tube inside the crossmember for the bolt to pass thru). The next ones will be installed with a good coating of Never Seize. For Chuck, the bolt had 3 hashs, signifying grade 5. I, nor Fatman, think grade 8 is the answer because while stronger in tensil strength, they are weaker in shear, which is what became lacking when the bolt work hardened. Going back to some of the other responses. I still think Fatmans is producing the strongest aftermarket units. His cross members are over kill, his thick walled tublar products are indestructable and the MOPAR ball joints are so much better than the flimsey OEM Mustang II. The bolt failure, for what ever reason, can occur on any other kit. Willys 36 is right in that the strut rod geometry of the origional equipment can not be beat ever by strut rod eliminators. Fatman did offer a solution to the cracking of the frame where the strut rod bracket is welded on and that is weld a 1/4 inch plate to the frame and then weld on a 2nd 1/4 " plate to provide the proper thickness for the strut rod bushings etc. This was to reduce the heat required to weld a 1/2" plate to the much thinner frame rail. Thanks for all the information sharing, guys.

Trees
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