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.

[Galcobar]

Symptoms sound quite familiar.

Worn-out bushing in a suspension arm, usually the inboard bushing on the No. 2 arm.

The suspension arms are the pieces which run in pairs laterally from the centre of the chassis to the rear wheels. They attach to the suspension member, which in turn is mounted to the chassis proper. The forward arm of each pair is the No. 1 arm, while the rearward arm with the threaded toe adjuster is the No. 2 arm. (All terminology drawn from Toyota's repair manual.)

When the bushing wears out, the arm can twist slightly and binds, then pops loose. The noise resulting is a dull clunk. You can often replicate the noise by compressing the suspension, but I found actually lifting the car slightly was more likely to produce the distinctive clunk. I would get under the car and lift it upwards with one hand on a suspension arm; if it's the problem the vibration when it pops is easy to feel. Prying at each bushing with a prybar may also allow you to isolate the source.

Toyota lists bushings (48725B) seperately for the No. 1 arm. The No. 2 arm is only sold with the bushings already pressed in -- probably a legacy from the fifth-gen when the No. 2 arm used a different mounting system. The entire No. 2 arm is still available from dealerships;1sttoyotaparts.com has them listed as front (No. 1) and rear control arms under the rear suspension section for $110 each.

Steff, aka hurley97, replaced her bushings with polyurethane -- but this required the use of a press, vice, air hammer, torch, air gun, a few hand tools and another person, and was done at a repair shop. Also, to remove/replace the No. 1 arm you have to at least lower the gas tank in order to remove the bolt holding the suspension arms to the suspension member.



I would suggest buying the nuts, bolts and washers if you're going to do this repair -- the outboard hardware was the most difficult set of connections I've ever had to disassemble on my Celica.

I converted my No. 2 suspension arms from the fifth-gen design, which set toe via an eccentric cam, to the sixth-gen's more robust threaded adjuster. Put together a write-up on the job, which is a reasonable guide for a sixth-gen remove/replace job. The primary difference is that on the sixth-gen both No. 1 and No. 2 suspension arms are mounted to the same bolt running through the suspension member, while the fifth-gen mounted the arms seperately at the chassis. The setup at the knuckel is effectively the same.

http://www.celicatech.com/forums/showthrea...mber-conversion