Rear Sway Bar & Clunking Noises in Rear of Vehicle

[dees71mach1]

Hi Everyone, I recently had some work done at a shop (transmission rebuilt, replaced rear differential pinion seal, & replaced master cylinder and brake booster.) I also had some new wheels and tires installed.

After picking up from the shop I started hearing a noise that resemble a jack rattling around in the trunk. I do not have a jack in the trunk but checked my trunk to see if something was amiss but there was nothing.

I returned to the shop where they examined and they thought the sound could be the rear sway bar. They noticed there are no bushings on the bottom of the sway bar but only on the top. I have attached some photos and would appreciate any of your comments if there should be bushings installed on the bottom or not and if it appears the bar is mounted correctly. What I can tell from my research is the bar is positioned correctly although I am not sure if there should be bushings on the bottom. You will also see the bushings that are there do need replacement.

However, this sound I am experiencing has never occurred and only started after I picked up the vehicle from the shop. I have also attached a video where I am pushing on the trunk and you can hear the sound.

I appreciate your thoughts, suggestions, and theories on what the culprit could be making this noise. Thanks!

 

[c9zx]

There are supposed to be two bushings on each end of the vertical link (8 total for both sides). Getting the bolt loose without breaking it is the hardest part of this job. Other than that it should be an easy fix. Chuck

If the bolts do break: https://www.amkproducts.com/product/f-3949/

 

[Hemikiller]

Them lifting the vehicle with the suspension hanging probably split the bushings and they just fell apart on your way home. Old rubber does that, not really their fault. You can see the top bushings are split and disintegrating as well. There's a pretty good chance your fronts are on their way out too. My recommendation is to replace the end links all around, and the frame bushings as well. Doing so will make a tremendous difference in your car's handling.

If you want to just replace the failed bushings, you can get a sway bar end link kit for the front, and use those bushings on the rear. Any parts store will have them. Looking at how little rust there is on the underside of your car, there's a good chance the bolts will come apart. To be safe, the shop should use heat and penetrant on the nut to ensure it doesn't snap the end link, as per Chuck's link, they are pricey.

https://www.npdlink.com/product/end...%2Blink&top_parent=200001&year=1971&year=1971
The 351 non-Boss cars with the rear bar typically received a 15/16" front and 1/2" bar. You can get frame bushings from Prothane for about $20/pair. They also sell the urethane end link kits.

https://www.prothanesuspensionparts.com/universal-sway-bar-endlinks.asp
https://www.prothanesuspensionparts.com/universal-sway-bar-bushings.asp

 

[dees71mach1]

There are supposed to be two bushings on each end of the vertical link (8 total for both sides). Getting the bolt loose without breaking it is the hardest part of this job. Other than that it should be an easy fix. Chuck

If the bolts do break: https://www.amkproducts.com/product/f-3949/

Thank you Chuck! You confirmed what I thought regarding bushings that were missing. Yes, I will get all of these replaced. You're car looks like mine! (Wimbledon White). I see you live in Mustang, OK; guess everyone there has to drive a Mustang?

 

[dees71mach1]

Them lifting the vehicle with the suspension hanging probably split the bushings and they just fell apart on your way home. Old rubber does that, not really their fault. You can see the top bushings are split and disintegrating as well. There's a pretty good chance your fronts are on their way out too. My recommendation is to replace the end links all around, and the frame bushings as well. Doing so will make a tremendous difference in your car's handling.

If you want to just replace the failed bushings, you can get a sway bar end link kit for the front, and use those bushings on the rear. Any parts store will have them. Looking at how little rust there is on the underside of your car, there's a good chance the bolts will come apart. To be safe, the shop should use heat and penetrant on the nut to ensure it doesn't snap the end link, as per Chuck's link, they are pricey.

https://www.npdlink.com/product/end...%2Blink&top_parent=200001&year=1971&year=1971
The 351 non-Boss cars with the rear bar typically received a 15/16" front and 1/2" bar. You can get frame bushings from Prothane for about $20/pair. They also sell the urethane end link kits.

https://www.prothanesuspensionparts.com/universal-sway-bar-endlinks.asp
https://www.prothanesuspensionparts.com/universal-sway-bar-bushings.asp

Thanks Hemikiller! I will pursue exactly what you recommended (as well as Chuck). I appreciate your links and references. Thanks so much! Brian

 

[Moderator73]

Wow that’s an incredibly loud sound and on such a great looking car. Darn it! I appreciate your short video and am anxious to hear what you end up doing to completely eliminate it. I’ve attached a couple pictures of what you should have. On these pictures the links are not yet tightened up because it’s best to have the axle at running height or close to it. I totally agree with Hemikillers comments. In fact if you’re up to putting another $500 bucks into your beautiful car ADDCO sells a great Front & Rear sway bar that’s slightly larger diameter than stock but wow did it make a huge difference on my convertible. It corners so flat with less roll than my modern cars. They were great to work with and it’s a real easy upgrade. Their kit gets you everything you need, links, bushings, brackets. I’m not trying to be a commercial here just sharing my personal experience. But that’s overkill for your situation & can certainly wait until another day especially after all you’ve put into your car that on this run. That’s huge.

 

[dees71mach1]

Wow that’s an incredibly loud sound and on such a great looking car. Darn it! I appreciate your short video and am anxious to hear what you end up doing to completely eliminate it. I’ve attached a couple pictures of what you should have. On these pictures the links are not yet tightened up because it’s best to have the axle at running height or close to it. I totally agree with Hemikillers comments. In fact if you’re up to putting another $500 bucks into your beautiful car ADDCO sells a great Front & Rear sway bar that’s slightly larger diameter than stock but wow did it make a huge difference on my convertible. It corners so flat with less roll than my modern cars. They were great to work with and it’s a real easy upgrade. Their kit gets you everything you need, links, bushings, brackets. I’m not trying to be a commercial here just sharing my personal experience. But that’s overkill for your situation & can certainly wait until another day especially after all you’ve put into your car that on this run. That’s huge.

Thanks for your note and compliments! I have looked at the ADDCO kit and was interested in pursuing that. Glad it made a big difference for your handling. Looking at your photos compared to those from mine, it looks like your bar is in an inverted position than how mine is placed/installed which is something I was wondering on my rear sway bar since even if I had the lower bushing in place, it does not appear the bar would lay flat and flush against the lower bushing. What are your thoughts?

 

[Moderator73]

From your pictures it looks like it’s oriented right. Two things that could make it look like it won’t line up are:
1-the car is jacked up. Try looking at it with the weight of car on the axle.
2-since the bushings are totally gone there’s nothing to help hold it right.
It should look a lot better with weight on it. For reference I’ve attached a picture of my stock (like yours) sway bar next to my ADDCO. Since the ADDCO is a little bigger the bend you’re seeing on mine may look more pronounced compared to your stock bar. I also attached a picture a little further back to where you can see the the bar placement better. If you look closely you can see the bar going across the gas tank and the tank rubber vent line at the middle. I hope this helps.
Bob

 

[c9zx]

Thank you Chuck! You confirmed what I thought regarding bushings that were missing. Yes, I will get all of these replaced. You're car looks like mine! (Wimbledon White). I see you live in Mustang, OK; guess everyone there has to drive a Mustang?

The cars look very much alike, I like the white. The City of Mustang doesn't require anyone to drive a Mustang. But, the people that want to enjoy driving a car have a Mustang. Chuck

P.S. There really are a LOT of Mustangs in Mustang.

 

[Stanglover]

As far a Addco anti-sway bars go, this thread might be of use.
This is what I did to my car after our friend Jpaz got Addco to remake the rear 990 bar correctly.
If you go with the 7/8 rear bar make sure it's the revised version. The front will be the 1 1/8" bar.
It was started by none other than Moderator73, Thanks.
https://7173mustangs.com/threads/rear-sway-bar.35165/post-387903