PontiacBonnevilleClub.com

I have been trying to locate the clunking noise in the left rear of my Bonneville for quite some time to no availl. I have read all the forums relateing to this, and have done the following;
1. New shocks (Monroe) noise still there
2. New upper shock mount. noise still there
3. Swapped the shock mounts from right to left. noise still there
4. Checked all bushings, they seem OK.

This clunking sound is only heard at low speed like driving through town when going over hard bumps like potholes or RR tracks. If I hit the same bumps at 50 mph there is no noise. Car is as quite as can be on the highway. It sounds as if its coming from the trunk area on the left. This is driving me crazy. Any Ideas

Some aftermarket shock mounts have been known to be noisy, and could be your problem. Another thing to check is the alignment link end. Jack up that side of the car, allowing the suspension to drop, then check the end of the alignment link to see if it pulled loose. Using one of Haro's pictures from his parts car, the arrow points to where to look.

I'm on this same crusade! I have now ordered the control-arm-to-body bushings (upper right in the pic), 2 per side, and expect to received them soon. If it's not the problem then I have to second Archon's suspicions. Loose alignment end links because I will have replaced everything else back there by then except the hubs but highly doubt hubs can be so cluncketty clunky.

I am still on this witch hunt to find the clunking sound in my rear suspension on the left side, ant more ideas?

What have you done since your original post?

I had a mechanic check it out and he said every thing looked ok, and thought the shock was making the noise on the left side. I took the shocks back and bought another set of Monroe shocks and put them on. Noise still there.

Do you recall what brand of mount you used? I know at least one member complained about the noise with Monroe mounts. You could try to get some good OEM mounts from a junk yard, or try some Moog mounts. I tried one on my car after having the same problem, and on the same side. They were at least as noisy when first put on, but settled down after a couple of weeks.

I originally used the original mounts, but when I still had the noise I replaced the left side with a Spicer/Raybestos mount from Rock Auto and still had the noise. I then switched the mounts from right to left and still had the noise. I don't beleive that the shocks are my problem with all that I have done to no avail. I can go over a hard bump or hit a pothole at a decent speed and never hear a thing, it mostly occurs at a slow speed around town hitting small bumps and going around corners that cause the suspension to shift. I really think its in a bushing but they all seem tight.

Peej: I have not yet replaced my rear trailing lower control arm (to body) bushings and the cacaphony of clunks has all but driven me around the bend. My order through a Moog supplier was on back-order forever and recently found out they don't even make them anymore.

I'm still confident that this is where the clunking is coming from - worn out rubber bushing that are really "loose" in their sockets at low speed but are perhaps under enough (trailing) pressure at higher speeds to not clunk. That's my theory anyway because I have replaced nearly everything else back there. The only time I found the noise to go away for a while was once after I had braked hard while in reverse and heard a rather loud clank in the rear as though something cracked or seated (possibly the control arm bushing reseating???).

I haven't had time to source out the part from another supplier yet. They are just a bitsh to find.

If anyone can find these lower control arm bushings for sale somewhere I would be much obliged. I beleive that my initial search found them to be the same part as the Olds Aurora uses (but not 100% sure).

You would definately think that if a bushing is loose enough to clunk that you would be able to feel it when you try to move it by hand. The sound still sounds like it is coming from the trunk area. Does your sound like its coming from the trunk? My car only has 72,000 miles on it and I have had junkers that didn't make a noise that I couldn't find.

Peej9089 wrote:You would definately think that if a bushing is loose enough to clunk that you would be able to feel it when you try to move it by hand. The sound still sounds like it is coming from the trunk area. Does your sound like its coming from the trunk? My car only has 72,000 miles on it and I have had junkers that didn't make a noise that I couldn't find.

Yeah, the low-speed pothole clunking noise is coming from the trunk area like right behind the rear doors. I have the sharp clunk noises from higher up (mounts probably?) and also associated "after-rattles" from lower down (lower control arms?).


the cold snap has broken so I may soon be going back under there for another look and see what it could be. I'll keep this thread posted.

I hope you find it because its driving me crazy

I get a squeaking and a clunking, so I know it's the mounts and the shocks are leaking so I need to replace those as well. More money!!!