Rear suspension knock., Searching wasn't helpful. Options

[richee3]

I recently installed TRD coilovers on the Celica to replace the aged stock suspension. The struts weren't totally blown but they weren't great and the springs had to have helper blocks in them, but they were quiet. After lowering, we found that the rear started knocking quite badly. Based on recent threads, I replaced the rear sway bushings with 16 mm with Energy Suspension bushings and the end links with Racing Beat Miata end links. While this cut the knocking down by half, there is still a persistent knock. It only happens at low speeds and seems to be from the right side more than the left, but it isn't strictly on one side or the other. All nuts and bolts have been checked and are confirmed to be tight.

When I searched, the only potential suspects I can find are trailing or control arms or the exhaust hitting the car. I don't believe it's the exhaust since it only happens at low speeds and I've followed the Celica and the exhaust seems stationary. So what are the odds that I need new rear bushings and it didn't become apparent until I was lowered? Anything else I should check? Any help or advice is greatly appreciated.

By the way, I'm intending to replace my rear bushings anyway, I just haven't done it yet. Procrastination is terrible.

[richee3]

If you're dropping the gas tank, and are looking to upgrade, a rear sway bar may not be a bad idea as well.
I hear they are a pain, and that most people have had to drop the gas tank a bit to get it in.
I would imagine having the rear arms, and the gas tank out would make it much easier to install.

I considered that a few months ago and started looking into Suspension Technique sway bars. I liked the price but when I started reading member reviews, I decide they were more than I need. This is the girlfriend's Celica and it's being built 70% comfort, 30% performance. Based on what I could find, members were saying the sway bars took a bit hit on ride comfort so I decided to leave the factory sways.

i got somebody else to remove the one bushing on the solid lateral arm years ago. when i asked them if they removed the gas tank, they said no. instead, the removed the 4 large bolts holding the subframe to the chassis and dropped the subframe. turns out it's an easier alternative than removing the gas tank.

Chris mentioned that as well. If I recall correctly he said it was either drop the subframe or the fuel tank. I've looked under the car but never really paid attention. I don't know how much work it is to drop either one. I can handle torching the old bushing out and pressing the new one in, but I suspect that dropping either the subframe or gas tank are more than I'm really willing/able to do at the moment. I still have a lot of research to do. I'll probably PM Dustin or Stef later and see if I can get an elaboration on what exactly Stef had to do at the shop to get the bushings in.