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.

[lagos]

It could be caused by your upper strut mounts. When the rubber inside of them wears out, they will knock while going over bumps.

[richee3]

Thanks Art! I'll check into it. I just thought it was odd that it would start knocking after lowering, then replacing two big culprits would only get rid of part of the knocking. I was thinking if any bushings were bad, we would have been able to hear them before the coilovers. Guess I'm SOL if the upper mounts are shot.

[trdproven]

retorque all nuts/bolts, check your sway bar bushings (you've done), inspect your endlinks, check if your calipers are making the noise. lift up your wheel do some comparison analysis spin the tire, spin with handbrake, jump on your trunk, try to replicate the sound, that way you can isolate it much better. these things must be thoroughly checked. It could be your pillowball bearing, is it while you are going slow and turning?

[richee3]

So far, no luck. I haven't been able to replicate/isolate the noise. I compared upper strut mounts between the old struts and the coilovers. I couldn't tell that one was worn any more than the other. The only difference I could see was that the center section was raised on the coilovers where it was more flat on the old struts. I'd have to get a picture to show what I mean, but it looks like it was done on purpose.

End links and sway bar bushings are new, so I can rule those out. All nuts and bolts were triple checked yesterday, so I can rule that out as well. What I can't figure out is why it knocks/rattles at low speeds only, regardless of the size of the bump. Above 15-20 mph, the noise completely disappears. Being an old car that has seen a few winters, the trailing and control arms look a bit aged. I'm thinking it MIGHT be an old bushing or something in there but I can't find anything loose.

[trdproven]

are the bump stops gone or are you bottoming out and your shock is dead? could be your pillowball bearing.

[richee3]

are the bump stops gone or are you bottoming out and your shock is dead? could be your pillowball bearing.

I'm not bottoming out, at least. I'll have to wait until next week when I've got more time to take everything apart and try finding the noise again. I've rode in the back seat to try to figure out whether the noise is coming from the top or bottom. It was difficult to tell. With no weight on the coils, I can spin the springs by hand but they aren't set up like my old springs, where the spring has to sit in a mount. I don't think this is the issue, however, since the springs can't move around- only spin in place. I'll have to wait until early next week to try to find anything though.

[trdproven]

did you remove the coilovers or just adjusted it? these rear knocking sounds especially rear right is beginning to be more obvious for our cars as of lately.

This post has been edited by trdproven: Jul 10, 2012 - 10:33 PM

[RabidTRD]

Ok if you figure this out, I really need to know. I've got the same damn issue. It only happens across small bumps like pebbles or slightly bouncy road. I thought it was the exhaust, but it's still doing it with the new one on. I have checked all my bars and everything is tight and solid! It's driving me mad! Right side rear, just like what you're talking about and it only started after putting my Koni's and Eibach's on.

I do know that one of my swaybar links is fuzzled, but it's on the driver side. I'll be replacing both with MOOG ones soon... so I'll update if that fixes.

[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

[richee3]

^^ Thanks! I'll have to test that next week when I get the time. I was planning on converting to the poly bushings like Stef, but I was going to do a few other things first. I find it odd that I never heard the noise with the old suspension, but then again everything is on a different angle now. Lots of little things to check on, first chance I get.

Rabid- if you beat me to it, let me know.

[trdproven]

seen that diagram to replace those bushings and arms a few times. was anyone ever successful with it? I noticed there were no updates or follow ups from people who bought it and installed it to say IT WORKED, NO MORE CLUNKS, YIPPEEE! does anyone know? and I read through as much search results possible.

suspension just has too much crap to check and replace assuming you can't identify the problem part or replicate the noise.

This post has been edited by trdproven: Jul 11, 2012 - 5:58 PM

[azian_advanced]

that's the diagram i made a while back. i noticed i had one bushing go bad so replaced it along with the sway bar bushings and my clunking went away. years later i got more clunking so i think the other bushings went bad. i bought polyurethane bushings to put in and only did the trailing arms but didn't get to put in the lateral arms for the rear. i was gonna complete the overhaul but my car got totalled. i have the poly bushings still here for the 4 rear lateral arms, brand new, still in the bag, if you're interested.

[richee3]

that's the diagram i made a while back. i noticed i had one bushing go bad so replaced it along with the sway bar bushings and my clunking went away. years later i got more clunking so i think the other bushings went bad. i bought polyurethane bushings to put in and only did the trailing arms but didn't get to put in the lateral arms for the rear. i was gonna complete the overhaul but my car got totalled. i have the poly bushings still here for the 4 rear lateral arms, brand new, still in the bag, if you're interested.

I'm definitely interested. PM'd.

[Galcobar]

The problem's actually fairly common. It sparked a few years worth of debate at Celicatech over the exact nature of the bushing, actually, as individuals replaced the arms to resolve that clunk. The All-trac fifth-gen definately used rubber bushings in the suspension arms, but the naturally-aspirated versions apparently used spherical bearings because the suspension movement was somewhat different. As a result, the fifth-gen owners had no choice but to replace the entire arm; well, they could theoretically have pressed out the bearings and replaced them but the cost of two bearings and the effort required made it impractical.

I wrote that how-to because I would see the question of a clunk from the rear suspension come up so often. Due to age it's a more common issue on the fifth-gens than on the sixth. I mention the testing procedures in this thread simply because of the cost of replacing all the possible sources of a clunk.

[richee3]

Thanks guys. I've got some stuff to test for sure when I get a chance, and hopefully I can find the source of the knocking. It's driving me crazy. It sounds like something is very loose in the rear end, but goes away above 15-20 miles an hour. If I hadn't rechecked them a couple of times already, I'd swear I left a nut or a bolt loose somewhere, but all the ones I've touched are tight. I guess lowering added enough stress to make an existing problem more obvious. I was planning on replacing my bushings anyway but Stef's thread scares me since I have no air tools. I'll probably have to pay to have that job done so I've been putting it off. It's going to happen eventually, so why not now?

[jordisonjr]

^ Yea those bolts also look like a royal pain to get off.
When I broke a bolt doing my sway bar bushings, i had to get it taken in to get drilled out, and the mechanic avoided unbolting one of the rear lateral arms, and did something else to access the bolt because it would have been too much of a pain to unbolt the rear lateral arm.

[richee3]

bloodMoney has a set of rear suspension bushings that I was talking to him about recently. He started to replace his and told me what a nightmare it was going to be, so I've been putting off getting a set of the poly bushings. Don't fix it if it isn't broken, after all. I figure I'll get those replaced now that something might actually be broken and if I still have knocking afterwards, I will bravely turn the radio louder and pretend nothing is wrong.

Unfortunately, I have no air tools and only a 2 foot cheater pipe to put on my 1/2" drive ratchet, so I don't think I can feasibly do this myself. I'll have to find a shop willing to do the work and pay outrageous fees for it. I'm only having this taken apart once, so I intend to replace my fuel tank straps, filler neck, and bushings all at once. Anything else I should replace while its apart?

[jordisonjr]

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.

[azian_advanced]

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.