fusion Posted August 12 Share Posted August 12 (edited) I have a 280z that I recently finished building. On the tension rods I installed brand new bushings. Rubber on the front side and poly on the back, as I believe was recommended by several people here. Torqued the nut to 40ftlbs. I was just under the car for something else and noticed that the rear bushings on both sides are split very badly. This is after only about 10 miles of driving. Wondering how this could be. I will switch the rear bushings to rubber but still want to know how this could have happened. Comments welcome Edited August 12 by fusion Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 13 Share Posted August 13 Actually it's rubber in the back, poly in the front. The front bushing takes the force under braking on the Z's, under compression, and is the one that you don't want compressing too much, making the steering squishy. But the poly should not have split. It does take a lot of side forces as the rod moves up and down with the suspension. But usually it causes the rod end to fatigue and break off. Seems like you got a bad batch of polyurethane. Bad chemistry, or a knockoff. 1 Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted August 13 Share Posted August 13 I used to run this: https://www.thezstore.com/product/6551/tension-rod-t-c-kit-70-8-87-240z-260z-280z-280zx-300zx It worked pretty well. I have since gone to rod ends and a clevis. Quote Link to comment Share on other sites More sharing options...
fusion Posted Thursday at 07:01 PM Author Share Posted Thursday at 07:01 PM On 8/12/2025 at 10:56 PM, NewZed said: Actually it's rubber in the back, poly in the front. The front bushing takes the force under braking on the Z's, under compression, and is the one that you don't want compressing too much, making the steering squishy. But the poly should not have split. It does take a lot of side forces as the rod moves up and down with the suspension. But usually it causes the rod end to fatigue and break off. Seems like you got a bad batch of polyurethane. Bad chemistry, or a knockoff. Hmm, well having the rubber and poly switched was pretty dumb of me. How much worse is it to have all rubber vs poly up front/ rubber on the back? This is a street only car Quote Link to comment Share on other sites More sharing options...
NewZed Posted Thursday at 08:24 PM Share Posted Thursday at 08:24 PM Probably just fine. The polyurethane products were developed as a performance improvement. More precise steering, less wheel movement. The aftermarket will hype and sell whatever they can. 1 Quote Link to comment Share on other sites More sharing options...
baby_Carlton Posted 2 hours ago Share Posted 2 hours ago On 8/14/2025 at 12:01 PM, fusion said: Hmm, well having the rubber and poly switched was pretty dumb of me. How much worse is it to have all rubber vs poly up front/ rubber on the back? This is a street only car Not dumb at all, though I definitely prefer rubber bushings over poly & solid in a street car even if its tracked 1-3 times/year. Quote Link to comment Share on other sites More sharing options...
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