viperredls1z Posted June 26, 2007 Share Posted June 26, 2007 If I had been inspecting this once in a while I might have noticed the crack that led to this failure. fortunately the tire was the only other damage. if you are running these control arms my advice would be to check for hair line cracks in the welds. as you can see in the photo mine was cracked for a while before it finally gave out. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted June 26, 2007 Administrators Share Posted June 26, 2007 Wow. Glad you're ok. One thing that bothers me about the design is the insertion depth of the threaded bung seems overly short. Not implying a longer one would have completely prevented it, but it would seem logical if it were longer and properly fitted, the stresses on the weld might be more manageable. Actual thread engagement might be an issue as well. I would not normally run less than at least 1.5 times the diameter of the thread engaged. Is this area bent?... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 26, 2007 Share Posted June 26, 2007 Dave, see those two threaded holes in the strut pictured above the broken part of the arm? Put bolts in there. It's a known ITS failure point discussed some years back by Dan Baldwin and katman as I recall, and putting a bolt in there essentially fixes the stress riser of the threads having been cut into the strut. With regards to this failure, the threaded section is clearly too short as Ron suggests. Whether or not that would have prevented the failure is something that could only be determined through testing. But a threaded tube end is 1.25" long if I remember correctly, and the max adjustment out of the threaded tube end should be about 5/16" on a 5/8" rod end. Your rod end looks to be turned out closer to 5/8". This would lead to a weakness in the rod end itself, but your failure happened at the arm (this time). Still, when you get your car running again you might consider turning the rod ends in a bit. If you need extra track width a wheel spacer would be a better way to go. What was AZC's response? How did you fix the arm? Have they changed the design? Quote Link to comment Share on other sites More sharing options...
mark Posted June 26, 2007 Share Posted June 26, 2007 THe inside of the arm looks pitted and rusty. Is it? Do you think this had a hand in the failure? Quote Link to comment Share on other sites More sharing options...
viperredls1z Posted June 26, 2007 Author Share Posted June 26, 2007 This is the repaired arm, the part in front is the threaded sleeve for the other arm. they are now plug welded in addition to around the circumference as the originals were. this is how all future arms will be made according to Dave from AZC. I did mine myself because I didn't want the down time of shipping both directions. Quote Link to comment Share on other sites More sharing options...
viperredls1z Posted June 26, 2007 Author Share Posted June 26, 2007 THe inside of the arm looks pitted and rusty. Is it? Do you think this had a hand in the failure? yes. I think moisture got in through a crack that I failed to notice, and the resulting rust helped speed up an inevitable failure. I don't think the rust caused the problem though. Quote Link to comment Share on other sites More sharing options...
MONZTER Posted June 26, 2007 Share Posted June 26, 2007 Do you think rosebud welds through the tube into the insert, and then overlaping the cross tubes would have helped, It sounded like a good when I was making mine, I hope so. cracks scare me... Quote Link to comment Share on other sites More sharing options...
DemonZ Posted June 26, 2007 Share Posted June 26, 2007 Looks to me the weld failed because not enough penetration. Quote Link to comment Share on other sites More sharing options...
jt1 Posted June 26, 2007 Share Posted June 26, 2007 I agree with DemonZ, the weld penetration looks suspect. Viper, can you post a straight on close up of the end of the tube where the weld was? John Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 26, 2007 Share Posted June 26, 2007 Do you think rosebud welds through the tube into the insert, and then overlaping the cross tubes would have helped, It sounded like a good when I was making mine, I hope so. cracks scare me... Looking at your first pic, I don't think 3/4" depth is enough on the threaded ends. From Aurora's website: Q What is the minimum thread engagement required to support the advertised load ratings in the Aurora Bearing Company catalog? A The minimum thread engagement is 1.5 times the major thread diameter unless otherwise stated. Unless I've done my math wrong (which is possible) you need 15/16" of threads inside the tube to fulfill the bearing manufacturers' requirement here. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted June 26, 2007 Share Posted June 26, 2007 Fascinating, especially in light of a string a couple of weeks back (cannot remember the name) included a brief discussion on modified OEM arms verses fabricated arms. Quote Link to comment Share on other sites More sharing options...
viperredls1z Posted June 27, 2007 Author Share Posted June 27, 2007 MONZTER those are some nice looking arms. Your design? Quote Link to comment Share on other sites More sharing options...
viperredls1z Posted June 27, 2007 Author Share Posted June 27, 2007 I wish now I had taken more pictures when this happened. this is all I have Quote Link to comment Share on other sites More sharing options...
viperredls1z Posted June 27, 2007 Author Share Posted June 27, 2007 Dave, see those two threaded holes in the strut pictured above the broken part of the arm? Put bolts in there. It's a known ITS failure point discussed some years back by Dan Baldwin and katman as I recall, and putting a bolt in there essentially fixes the stress riser of the threads having been cut into the strut. Thanks for the tip Jon Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted June 27, 2007 Administrators Share Posted June 27, 2007 Dave, Is that little rod dangling out the bottom of the strut tube an adjuster for your strut/damper valving? If you don’t mind, what dampers are running? Thanks, Paul Quote Link to comment Share on other sites More sharing options...
arizonazcar Posted June 27, 2007 Share Posted June 27, 2007 First failure I know of in 18 years and hundreds of parts made.....the design has been well proven and been highly reliable. I continue to have a lot of confidence in them. Even so I am incorporating a longer threaded insert into the current batch to reduce (eliminate?) the chance of a repeat. It is also being plug welded Carefull inspection of ALL racing components is essential in order to catch problems before they occur. viperredls1z's (Dave Kipperman) part failed after several years and thousands of race miles, it might have been caught earlier before it broke. Dave K. has been a long time customer, racer, and installer of my products and is one of my current BETA testers. I really appreciate his input and suggestions as hopefully the members of Hybrid Z do. Sincerely Dave Epstein Owner ARIZONA Z CAR 2043 E. QUARTZ ST. MESA AZ 85213 480-844-9677 dave@arizonazcar.com http://www.arizonazcar.com Quote Link to comment Share on other sites More sharing options...
viperredls1z Posted June 27, 2007 Author Share Posted June 27, 2007 Dave,Is that little rod dangling out the bottom of the strut tube an adjuster for your strut/damper valving? If you don’t mind, what dampers are running? Yes Paul, that's an extension from the adjuster. the shocks are the current AZC setup. Quote Link to comment Share on other sites More sharing options...
MONZTER Posted June 27, 2007 Share Posted June 27, 2007 MONZTER those are some nice looking arms. Your design? Thanks for the comments, Ya there mine, made just 1 set for my personal project Jeff Quote Link to comment Share on other sites More sharing options...
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