RebekahsZ Posted July 18, 2015 Share Posted July 18, 2015 (edited) Did a little bit of agricultural work at ZCON when I was supposed to be autocrossing. You might say, that in the heat of the day, I found the cool green grass to be preferable to the official driving surface. And thereby experienced a minor component failure in what I think was wheel vs the back side of the gator curbing. I was afraid to try to repair this and continue the driving events, thinking that by bending the clevis back straight, I might cause a crack. A show of hands: who would have had the balls to take this TC rod off, straighten it with a hammer and get back on the track? Edited July 18, 2015 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
rturbo 930 Posted July 18, 2015 Share Posted July 18, 2015 Uhh, I'd say you made the right decision. No way in hell would I try reusing that. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 18, 2015 Author Share Posted July 18, 2015 (edited) Here's a better photo. I'm starting to consider that those of us who drove the car may have gotten this TC rod bent a little out of line with heavy braking and curb hopping, perhaps finalized with a final off-track excursion after 7 or 8 spins (some on track, some off track, all thru either the S's, which have curbing, or one of the cone slaloms). I'm also willing to consider the possibility that the final off-track spin in a cone slalom was CAUSED by the failure, rather than the other way around. My wheels and tires look fine and are nice and round without rim damage. Which makes me skeptical that a single impact with a curb was to blame. Plus, the other side doesn't look 100% straight either. More updates as I learn. I'm certainly not upset nor eager to cry foul in any way-there was a team of angry drivers that were beating the hell out of the car, and everything has its limits. And I was have more fun than any of them, and I still am. Edited July 18, 2015 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
whatnow123 Posted July 18, 2015 Share Posted July 18, 2015 I wouldn't have drove on that! I am wondering how it happened, it was a "blunt force" as that would be plenty strong to just hold the wheel in place. And did I read your post right? You are letting other people (a lot of other people) drive your car? Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted July 18, 2015 Share Posted July 18, 2015 What size clevis end are you using, and what thickness is the plate for the curved attachment to the lower control arm? I have a very similar set-up, but my clevis has a 3/4-16 thread and my attachment plate is 3/8" thick. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 18, 2015 Author Share Posted July 18, 2015 (edited) 74-I will edit this when I measure to get you an answer. I'm kinda thankful for the way this failed, the clevis was ductile and bent rather than breaking, and I THINK the clevis and plate took the damage instead of the TC box in the rail. That's a real plus. So, I actually feel pretty lucky. I'm looking into the T3 rods next since I have his LCAs. I have to find my receipt, but I think these are from Datsun Parts LLC. Johnc turned me onto them. I like them, they are easy to work with and don't want to bash them one bit. I have an extra pair of tubes that allow me a lot more caster, and I already had plans to use those to try to keep the wheel straighter on landspeed. The flat steel plate bent at one of the drilled holes, a likely point of failure. If I can get replacement clevis-s, I may just cut new plates with more material around the bolt holes and get back to business. And sure, I let other people drive my car. They never fail to exit with a big grin on their faces. This sport isn't that fun all by yourself. Plus, I like to watch the car run. I should have been more selective (not with drivers, but with venue). This was supposed to be an autocross, but it was on a track, and I was personally topping 100mph at corner entries. My car sharing is really more based on a parking lot full of cones. Funny-I was definitely the cone killer of the event. If the MC at the banquet has any sense of humor, he should really roast me! Edited July 18, 2015 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
johnc Posted July 18, 2015 Share Posted July 18, 2015 That is a good type of faure as Keith mentioned. You will need to check the tube for straightness and cracks. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 18, 2015 Author Share Posted July 18, 2015 (edited) Yeah, John, I'm wondering if I should stick with them for that very reason. I just wish that little metal brake line that tucks under the rail had been 1/2-inch to either side-the TC rod put a nice little crush in it. A bunch of brand new RB600 is about to get wasted when I replace that crushed line. All the luck! Seems I can't change a side marker bulb without having to bleed brakes! Edited July 18, 2015 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted July 18, 2015 Share Posted July 18, 2015 (edited) That is definitely the preferred failure mode. Years ago, I had one fail by fracture (different set-up than I am currently running). Not a pretty thing. You can see the bent TC tube on the ground in front of the car. It had fractured in the threaded portion adjacent to the attachment at the LCA. Edited July 18, 2015 by 74_5.0L_Z Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 18, 2015 Author Share Posted July 18, 2015 (edited) 5/8" on the clevis thread size. 74_, what did you hit to do that? I just cleaned up my tires to go back in cool storage when they dry. The number of flat spots on the front tires makes me doubt the wisdom of "both feet IN!" I'm thinking that if you are headed off the track backwards, a better policy would just be "Left Foot IN!" I have spare used tires and they tend to age out before wearing out. So it's all good. Edited July 18, 2015 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
heavy85 Posted July 19, 2015 Share Posted July 19, 2015 Do you know where the ball joints on the chassis side came from? I'm guessing they are steering tie rods off something? Quote Link to comment Share on other sites More sharing options...
tube80z Posted July 19, 2015 Share Posted July 19, 2015 I've done a few sets like that and used Subaru inner rack ends. They are metric but look very similar. I've seen some Triumph or MG products that were similar but probably standard threads. Keith, the clivice is a standard part you can order from speedway or summit. For the plate I'd recommend a higher grade steel than mild. My local steel supplier has a plate they call formaloy 4040 or something very similar that is a lot stronger than mild steel but will still bend rather than brake. For any 0.25 inch brackets I like to use it. One option for these is to make the hockey stick out of an old TC rod. You will need to grind for clearance to make it work with a 5/8 clevis. Your next step up is 3/4 and a thicker hockey stick and it may not bend. But that means something else might. Cary Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 20, 2015 Author Share Posted July 20, 2015 You guys are giving me great advice and I really appreciate it. I think I want to stay with the same kit and just replace the clevis(s) (clevi?)(clevae?)(clevises?) and the hockey sticks. I'm registering tube80z's steel alloy recommendation, any other alloy suggestions in case my local supplier can't get it? I'm wondering what the minimum order is gonna be-probably a 4x8 sheet-argh! I guess if I bend another one I will make a big change, but as you said, the damage will just get pushed farther down the line. I really wish I knew HOW this occurred-I didn't feel us hit anything solid at all as we were spinning, and I wasn't freaking in the passenger seat or anything like that-I had my eyes open and my brain engaged the whole time. If anything, I was probably laughing cause none of my friends could stay on the track any better than I could. Quote Link to comment Share on other sites More sharing options...
KAZU Posted July 20, 2015 Share Posted July 20, 2015 You can see in this figure how it happened. Combination of TTT lca with Datsun Parts LLC TC rod was bad. I also have Datsun Parts LLC TC rods with lengthened Nissan lca. It survived major crash which bent shock rod and wheel rim. More thread engagement than yours. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 20, 2015 Author Share Posted July 20, 2015 (edited) Hmmm. I went with the T3 LCA to allow use of a spherical bearing so that I could easily change caster. So, perhaps even braking forces are putting that clevis in a bending moment via the small moment arm created by that offset described in your diagram, and not just a compression force. I see your point. I wonder if the bend started in the dog leg or the clevis. I really appreciate the input. Maybe a gusset or stiffener in the flat plate of the dog leg would help. The TTT T-C rod still used a flat plate dog-leg... I'm starting to wonder if threshold braking alone could have initiated this bend, or maybe threshold braking into a gater/corner curbing? I was smackin' me some gaters even when I wasn't leaving the paved surface. I was trying to win, so I was hitting the gaters under either steady state throttle or acceleration. The very first off-track of the day was by someone else and left two straight black marks right thru the esses, At least 2 gaters were crossed head-on with locked front brakes. Edited July 20, 2015 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
KAZU Posted July 20, 2015 Share Posted July 20, 2015 (edited) TTT TC rods look like stronger, at least no clevis threaded shaft. Adjusting threads are located the other end where the bend moment may be ignored. But their fixed angle dog-leg do not allow adjusting the tread width and caster angle. My guess is that the clevis shaft bent slightly under the threshold braking which worsened the situation. Already bent clevis got bent more easily. Finally under the hard braking or the corner carving the LCA rotation was stopped by the ball joint motion limit, then both the clevis and dog-leg bent simultaneously. Edited July 20, 2015 by KAZU Quote Link to comment Share on other sites More sharing options...
tube80z Posted July 20, 2015 Share Posted July 20, 2015 You guys are giving me great advice and I really appreciate it. I think I want to stay with the same kit and just replace the clevis(s) (clevi?)(clevae?)(clevises?) and the hockey sticks. I'm registering tube80z's steel alloy recommendation, any other alloy suggestions in case my local supplier can't get it? I'm wondering what the minimum order is gonna be-probably a 4x8 sheet-argh! I guess if I bend another one I will make a big change, but as you said, the damage will just get pushed farther down the line. I really wish I knew HOW this occurred-I didn't feel us hit anything solid at all as we were spinning, and I wasn't freaking in the passenger seat or anything like that-I had my eyes open and my brain engaged the whole time. If anything, I was probably laughing cause none of my friends could stay on the track any better than I could. T3 plate or CrMo plate or stock TC rod modified. You should be able to get small samples if not there are online metal dealers. To fix the offset shear issue you can do double shear with a solid rod end. That was the planned next step if the single stick didn't cut it. But we never had a problem on a car that can break at 1.4gs so figured we were good. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 22, 2015 Author Share Posted July 22, 2015 Should I get plain steel or stainless steel clevises? There's no rust on what I have, so I guess it's stainless?? Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted July 22, 2015 Share Posted July 22, 2015 (edited) Regardless of the clevis that you use, I would make the attaching bracket to the control arm with a little more material around the hole and around the bend plane. Attached is a link with the drawing used to make my bracket. Mine was made using 1020 mild steel, but you could step up to 4130 for more yield strength. http://forums.hybridz.org/topic/41611-tc-rod-pivot-relocation-bad-dog-subframe-connectors-slotted-crossmember/page-6 Edited July 22, 2015 by 74_5.0L_Z Quote Link to comment Share on other sites More sharing options...
1 tuff z Posted July 22, 2015 Share Posted July 22, 2015 Magnet check? Quote Link to comment Share on other sites More sharing options...
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