05 right rear knock

[wayne rubel]

After one year of dealers ,looking for the knock and replacing struts and mounts they said there wasn't anything else they could do. So I thought 'before I go bulistic on these guys I will have one more look and dig a little deeper. By riding in the trunk and my buddy driving over a specific pot hole in my driveway I was able to icolate the location of the knock; right above the muffler. Packed temperary foam around muffler and it was no different: still knocked.Took foam out . I looked up from underneath behind the decortive plastic bumper above the muffler. I saw a cast iron box on rubber mounts, mounted on the structual steel bumper. Hitting it with my hand made the same knock. I packed permanent foam around that box and the noise was gone. When I asked the dealer what the box on rubber mounts was, he had to look it up. Get this , it a VIBATION DAMPENER! of all things.doe!!!!!!!!!!!
Anyway I didn't want them touching the car again , so I just leave the foam in and it is knock free. Hope this post helps some.

[ClassySolaraGuy]

Glad to hear you fixed your problem...Dealers SUCK!

[oldkystude]

When I asked the dealer what the box on rubber mounts was, he had to look it up. Get this , it a VIBATION DAMPENER! of all things.doe!!!!!!!!!!!
Anyway I didn't want them touching the car again , so I just leave the foam in and it is knock free. Hope this post helps some.

Convertible, right? For some reason convertibles need those things. I would get a GOOD dealer to replace it though. I will look up the service bulletins and see if they have anything about this problem. I am also going to look at it on the final assy line tomorow as I have only seen a drawing of it.

Convertible designs are very interesting to me as I have a 48 Studebaker Convertible. Studebaker also used a pair of Vibration Dampers in that car but some jerk removed them from mine and I can't find any. (The car is not drivable, but I want to restore it someday.) In that car they consist of heavy cast iron weights about the size of grapefruit attached to the front frame by a short leaf spring and bracket. On the later Lark Convertible they just bolted lead bars into the lower lip of the front panel under the grill.

Those things are important. I will report back. HP

[wayne rubel]

Yes it is a convertible.
That would be awesume if you could see it on the assemble line ,and find out what it realy does.Its good to have friends in high places. Thanks!!
I was actully thinking about puting expanding spray foam around it. What do you think?
The dealer has all ready installed a new one a year ago but it does the same thing. What would happen if they took it off all together?

[oldkystude]

Yes it is a convertible.
That would be awesume if you could see it on the assemble line ,and find out what it realy does.Its good to have friends in high places. Thanks!!
I was actully thinking about puting expanding spray foam around it. What do you think?
The dealer has all ready installed a new one a year ago but it does the same thing. What would happen if they took it off all together?

Thanks for the compliment but I will never achieve a high place here. Too many CLBs on file. (Career Limiting Behaviours) I fuss a lot about safety stuff..

Keep having them replaced. You need to keep the records also as they obviously have a problem and you will want a paper trail to be sure they give you a good one when they finally figure it out. I will talk to a buddy in Quality to see if he can find something out.

Please forgive the long expanation now. I am also a helicopter mechanic and that helped me figure out why these dampners are on certain cars:

Every object has a natural frequency that it wants to vibrate at. We usually think of tuning forks and that the longer ones have a lower note because they vibrate at a lower frequency. It is a real problem in helicopters because the human body has a natural frequency that is very close to the RPM of main rotors. Whenever you hear some radio station traffic guy in a helicopter and his voice is vibrating, that is because his body is at that frequency. It is very uncomfortable when you hit it perfectly in some organ like your eyeballs. Main rotors revolve in a very narrow speed range so you can get out of it but what is comfortable for you is hell for your skinny friend. helicopter designers work very hard to isolate the cabin from all those pulses, but just the blast against the roof is enough to shake the machine.

One device we had in the structure of our Aerospatial Twinstar was a pair of 2 pound lead weights attached to leaf springs under the floor boards. The weights could be shifted on slotted holes and the factory supposedly had them set at the best spot when the machine was built. I always suspected they needed to be adjusted after we put in a new interior, but it was a big project and we were satisfied with the ride we had.

Those weights looked exactly like small versions of the ones in my 48 Studebaker Convertible. In those days when a car body's natural frequency was the same as the wheel rpm, and you got that uncomforable resonance going it was called "Wheel Tramp". (insert joke here, but that was the name.)

Sedan bodies do not have a natural resonance that is close to the wheel rpm, even back then. Obviously they are also much stiffer, which is probably the main reason since the dampners are still in use on our Solara convertibles.

Whether spring mounted or in a rubber mounting they perform the same function. They shift the car body's natural frequency to get it away from wheel rpm ranges. Don't think of them as bobbing around in rubber. Think of them as your car body's anchors in the fabric of space/time.

If you take them out you will either have an uncomfortable ride, or the atmosphere will catch fire. HP

[oldkystude]

If anyone knows of others having this problem please contact me.

Sometimes we know of problems at the plant that dealers are not aware of. I had a 94 Camry that the dash air vents popped out of place and fell into the duct. The dealer was a total jerk. said we obviously put our feet on it and pushed it out. I am too old and fat to accomplish this act, but he was not to be swayed. I contacted our QC mangaer and brouht him the part to look at. He was surprised to see it as they thought they had gotten all the bad ones out of the system. (Vendor problem.) he offered to speak to the dealer directly if I needed help with the warranty. When I offered the dealer his number I was told "we don't have anything to do with those factory people, your warranty is still denied."

Jerk-ass from hell.

Found a good dealer and got it replaced free in a week.

I digress. I shall check at the plant though just in case QC knows about bad vibration dampners in convertibles.

[PXLpainter]

^^ So much great info!

I vote for giving this guy his own tech forum!

[wayne rubel]

After 2 1/2 years of dumb looks, engineres test drives, calls and reports made to toyota themself, and me showing them exactly where the problem is and how I delt with it,this is the first intellegent response. And it helps so much to help me understand. Thanks oldkystud, and SolaraGuy for making it possible.
Anyother information is greatly appreciated.

[oldkystude]

After my shift I went on a quest and talked to the guys who install this thing. They said it has not changed since SOP of the convertible. If you ever get yours replaced again take a photo so the rest can see it please.

It is odd that it is mounted toward the right side of the rear bumper, not in the center. The cast iron piece has something inside it as there is a metal plate attached to the bottom of the casting, and the casting has a triple cylinderical shape which suggests exotic contents.

The casting is suspended by a thin stainless spring and has round lugs on each end with rubber bumpers. I get the feeling that the rubber bumpers are supposed to be the last resort but it was not suposed to hit them often, just in extreme jounces.

It comes from Japan. Vendor unknown.

Not much info, but thought I would report back anyway. Will try to get a name from my buddy in QC tomorrow and see if I can find out more. It was fun watching the convertible assy processes anyway.

Hung around for about an hour and followed a few down the line. Don't get out to final lines much and always get a kick out of seeing the processes. Sedan production is down to 40 per day. Convertibles are up to 84. Sales on these cars must really suck, as we make a car every 28 seconds over 2 shifts. They sure look great, wish someone would buy more of them....

[wayne rubel]

thanks for all your info