Rattle in the Rear End

Peej9089 · Post by **Peej9089** » Sun Aug 23, 2009 7:10 pm

After almost a year off and on of trying to find a rattle at low speed going over bumps I finally found the problem. I replaced the shocks, new shock mounts, and even replaced the left torsion bar to no avail. Finaly I discoverd that one of the body mounts under the rear door had somehow rusted around the mounting bolt. After removing the bolt, installing a larger washer and re tighting, the rattle is now gone

. I know others on this site have the same rattle so I thought I would post this along with some pictires. Thanks to all of those here that tried to help me with their ideas when I posted for your help

golfyeti · Post by **golfyeti** » Thu Oct 18, 2012 6:13 pm

After almost a year off and on of trying to find a rattle at low speed going over bumps I finally found the problem. I replaced the shocks, new shock mounts, and even replaced the left torsion bar to no avail. Finaly I discoverd that one of the body mounts under the rear door had somehow rusted around the mounting bolt. After removing the bolt, installing a larger washer and re tighting, the rattle is now gone . I know others on this site have the same rattle so I thought I would post this along with some pictires. Thanks to all of those here that tried to help me with their ideas when I posted for your help

Adding the word clunk to this thread as this is what it sounded to me mostly, with a rattling sound following it.

01bonneSC · Post by **01bonneSC** » Thu Oct 18, 2012 6:20 pm

Holy old thread!!!!

golfyeti · Post by **golfyeti** » Thu Oct 18, 2012 8:23 pm

Old yes, but it is the only post on this entire forum that solves an irritating loud clunk and rattle every time your rear end goes over the slightest bump or pot hole. Everyone here immediately (as I did) fixates on shocks and shock mounts as the culprit. Lots of money has been spent tryng to nail down that aweful problem so I hope people will remember this solution for others, especiallly if they still have clunk and rattle issues after replacing shocks and mounts, like I did twice over.

2002FO · Post by **2002FO** » Sat Oct 20, 2012 9:40 am

Great information. Old thread, yes... But still very pertinent... I ordered new shocks and Moog mounts off eBay and since I'm on vacation, I'll be swapping them out next week since they're probably 4 years old. Also will be looking at those suspension mount bolts.....

Ooooh I can't wait....

spoiledred94 · Post by **spoiledred94** » Sat Oct 20, 2012 12:17 pm

I have a light rattle back there too. Does your rattle sound kinda like thin sheet metal (maybe the heat shield) rattling on its mounts? At any rate I'll see if I can locate those bolts and take a look.

2002FO · Post by **2002FO** » Sat Oct 20, 2012 1:18 pm

No, I've experienced that as well (replaced the cat about 3 years ago) and this annoyance sounds exactly like something just bouncing around in the trunk.

spoiledred94 · Post by **spoiledred94** » Sat Oct 20, 2012 2:15 pm

I'll see if it's my cat, feels like farther back. As far as the struts yeah me too now that I think of it. I replaced my rear struts, on my 94 Se, and had a pretty loud heavy rattle on rough street. Never fixed it and now she's gone...

maroon111993 · Post by **maroon111993** » Sun Oct 21, 2012 2:30 am

I was about to order new struts because of this. But now I'm goina check to see if mine is the same problem. Thanks!

maroon111993 · Post by **maroon111993** » Mon Oct 22, 2012 1:06 pm

Anyone happen to know where these are on the 97-03 Grand Prixs?

2002FO · Post by **2002FO** » Wed Oct 24, 2012 1:55 pm

Just did the washer trick on both forward suspension mounts, and...... Nothing...

No change. Still clunks over the slightest little bump. So, tomorrow morning, I'll tackle the shocks and mounts and we'll see what happens....

Post by **BlackHawk99** » Wed Oct 24, 2012 2:06 pm

Try checking these bolts:

http://www.pontiacbonnevilleclub.com/fo ... 34150.html

I had a similar issue and it ended up being those bolts which were loose.

maroon111993 · Post by **maroon111993** » Wed Oct 24, 2012 2:15 pm

BlackHawk99 wrote:Try checking these bolts:

http://www.pontiacbonnevilleclub.com/fo ... 34150.html

I had a similar issue and it ended up being those bolts which were loose.

Thanks! I'll check it out.

maroon111993 · Post by **maroon111993** » Wed Oct 24, 2012 2:23 pm

Actually, i don't have this.. :/ Any other ideas? How do I re-tighten the shocks?

maroon111993 · Post by **maroon111993** » Wed Oct 24, 2012 3:25 pm

When it's on the ground, and I bounce it up and down by pushing on the trunk, I hear a 'click click' every time the car goes down... but it doesn't sound like it's in the strut. It sounds like it's coming from behind the rotor.. I've looked behind there and nothing is broken, either..

Post by **BlackHawk99** » Thu Oct 25, 2012 6:55 am

maroon111993 wrote:Actually, i don't have this.. :/ Any other ideas? How do I re-tighten the shocks?

Sorry, I didn't realize you had a Grand Prix. Like Haro said in the other thread, we're not going to be a lot of help to you.

Ken_W · Post by **Ken_W** » Thu Oct 25, 2012 11:36 am

Get in the trunk with a flashlight and have a friend drive you around over some bumps. Remove the cover from your shocks beforehand (if GP's have one) and watch this as you go. You will know pretty quick whether it is your shock or not, as you will see the circular disc raise up from the shock mount and then bang back down. If not, listen carefully and shine your light where you hear noise. If it is coming from inside the trunk, there is no better way to be certain.

If it is coming from underneath the car, the trunk check will hopefully help you to confirm this. In this case, lay down next to the car while a friend pushes down on the rear end. Shine your light around and try to find where the click is coming from.

If it does turn out to be shocks, and if the design is the same as Bonnevilles, you need two wrenches to tighten the upper center shock nut further. Hold the center shaft steady with one wrench while tightening the nut (clockwise when looking at from above) with the other. It is a little awkward, but you will eventually figure out how to do it. Turn the nut a quarter-turn, then test-drive and see if it got better. If not, do another quarter turn. It should be pretty hard to turn at this point; if not, maybe do a third quarter-turn.

Ken_W

maroon111993 · Post by **maroon111993** » Thu Oct 25, 2012 12:45 pm

Ken_W wrote:Get in the trunk with a flashlight and have a friend drive you around over some bumps. Remove the cover from your shocks beforehand (if GP's have one) and watch this as you go. You will know pretty quick whether it is your shock or not, as you will see the circular disc raise up from the shock mount and then bang back down. If not, listen carefully and shine your light where you hear noise. If it is coming from inside the trunk, there is no better way to be certain.

If it is coming from underneath the car, the trunk check will hopefully help you to confirm this. In this case, lay down next to the car while a friend pushes down on the rear end. Shine your light around and try to find where the click is coming from.

If it does turn out to be shocks, and if the design is the same as Bonnevilles, you need two wrenches to tighten the upper center shock nut further. Hold the center shaft steady with one wrench while tightening the nut (clockwise when looking at from above) with the other. It is a little awkward, but you will eventually figure out how to do it. Turn the nut a quarter-turn, then test-drive and see if it got better. If not, do another quarter turn. It should be pretty hard to turn at this point; if not, maybe do a third quarter-turn.

Ken_W

Hmm. I'll give that a try. Thanks to the 'bonnevillians' who are giving me their best shot. haha

2002FO · Post by **2002FO** » Thu Oct 25, 2012 4:00 pm

Well, I just finished the shocks and mounts. FIXED!!!

Yup, no more rattles. I can't believe how quiet the car is driving on these Milwaukee city streets.....

Wasn't too hard. The only sticky part was getting the air line out of the passenger side shock. That was a lil difficult.

Everything went together very well and what a difference!

BTW, I used Moog mounts. Don't skimp with stuff like this. (See my sig...)

PontiacBonnevilleClub.com

PontiacBonnevilleClub.com

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