[StarFire_MK2]

Hi all,

I replaced all the worn bushings on my 1-1/16” front swaybar (87 Sundance) with the appropriate Mopar bushings. The steering nicely tightened up, and all the thunking from the front end stopped. Two days later, the thunking came back, albeit much quieter. I went back under the car, and noticed the bar-to-frame bushing on the driver's side was already distorted. I assumed I installed it incorrectly, so I went and bought another set, and carefully replaced it. I added some silicone lube to the bushing as well.

A month later, I am still getting thunking noises from this area. I went under the car last night, and noticed the same bushing was slightly out of alignment on the bar...the "top" and "bottom parts of the bushing were not aligned. I loosened the bar, realigned it, and tightened it down. I also tightened the bolts a bit more on the driver’s side end bushing bracket. This has reduced the thunking, though not eliminated it. I’m not having problems with any of the other bushings.

Any thoughts on what the problem is? I have one more bushing left.

 

[Bob Lincoln]

The swaybar can actually hammer a flat spot in itself if the original bushing was too far gone, and it's hard to spot this.

Also, there are slightly different diameter bars, and it's possible that someone gave you the wrong diameter bushing.

 

[Dave Z]

Yes, they often give you the wrong bolts in these packages, I had that problem in my Spirit R/T and had to put the orignal bolts back in!


PS> Bob L is more likely right

 

[StarFire_MK2]

The swaybar can actually hammer a flat spot in itself if the original bushing was too far gone, and it's hard to spot this.

Also, there are slightly different diameter bars, and it's possible that someone gave you the wrong diameter bushing.

The bushings are the correct size; I measured them before I left the store.

As for the flat spot, is that something that can be shimmed?

 

[ImperialCrown]

You have replaced all 4 rubber bushings?
2 in the crossmember and 2 at the front control arms?
There should be no lube applied as these need to go in dry.

 

[StarFire_MK2]

You have replaced all 4 rubber bushings?
2 in the crossmember and 2 at the front control arms?
There should be no lube applied as these need to go in dry.

Yes, I replaced all four. I only tried lubing the driver's side frame-to-bar bushing when I replaced it the second time, and learned you are correct in saying it needed to be dry. It made a racket!

Can one shim the bushing? Cut a piece of metal to fit inside the bar-to-frame bracket, or cut a 1/32" tube to fit over the bar-to-bushing "joint"?

 

[StarFire_MK2]

Update:

I created a series of shims out of some heater hose I had laying around. I carefully cut and flattened them out and mounted them to the outer portions of the bracket. This has solved 90% of the noise I was hearing. Since I put the shims in, I may go days without hearing anything at all from that bushing, and it's much quieter when I do.

Perhaps its not an ideal solution, but I thought I'd share it. For those who attempt this, make sure you your shims do not interfere with the projection on the bottom of the bushing: this needs to seat into the matching groove in the bracket itself.

 

[Bob Lincoln]

Still sounds like the bushings were too small. Measuring the used ones wouldn't give you accurate measurements. Better to measure the diameter of the bar and buy the bushings that it calls out.

 

[John Wood]

I'm not sure this is the case here, but I once had a problem with the sway bar ends making slight contact with the lower control arms. I went through a lot of what you have been doing. I finally figured it out when I took the bar off for the 3rd-4th time and crawled completely under the vehicle for inspection. There was a small shiney mark on the lower control arm where the end of the bar had made occasional contact, especially if it shifted off center a bit over time. My solution was to cut 1/8" off the ends of the bar and re-install (using new bushings, of course). My theory was that the bar had expanded slightly at the bends from years of twist applied to it everytime the car goes over an uneven surface. That resolved my problem with noise. The shimming that you have done, may accomplish the same thing by providing a slight amount of more space between the end of the bar and the lower control arm.

If you ever have to shave or cut the bar ends, you will find that it is extremely tough steel. I had to use a cutoff tool with good safety goggles, as the sparks were flying furiously.

 

[bamman]

Another thing, the sway bar can also be installed upside down. I've done it before.

Try flipping the bar over to see if that fixes it.

It sure did solve my thunking problem. Orienting the bar one way makes it hit the control arm, the other way it is clear.

 

[StarFire_MK2]

Still sounds like the bushings were too small. Measuring the used ones wouldn't give you accurate measurements. Better to measure the diameter of the bar and buy the bushings that it calls out.

I didn't measure the old bushings. I measured the bar, and then measured the new bushings the store provided to make sure they gave me the correct size. The new bushings are the correct size.

I'm not sure this is the case here, but I once had a problem with the sway bar ends making slight contact with the lower control arms. I went through a lot of what you have been doing. I finally figured it out when I took the bar off for the 3rd-4th time and crawled completely under the vehicle for inspection. There was a small shiney mark on the lower control arm where the end of the bar had made occasional contact, especially if it shifted off center a bit over time. My solution was to cut 1/8" off the ends of the bar and re-install (using new bushings, of course). My theory was that the bar had expanded slightly at the bends from years of twist applied to it everytime the car goes over an uneven surface. That resolved my problem with noise. The shimming that you have done, may accomplish the same thing by providing a slight amount of more space between the end of the bar and the lower control arm.

If you ever have to shave or cut the bar ends, you will find that it is extremely tough steel. I had to use a cutoff tool with good safety goggles, as the sparks were flying furiously.

Interesting. I'll check that, thanks!

Another thing, the sway bar can also be installed upside down. I've done it before. Try flipping the bar over to see if that fixes it. It sure did solve my thunking problem. Orienting the bar one way makes it hit the control arm, the other way it is clear.

Hmmm, I'm almost certain installed it in the same orientaion as it came out, but I'll check.

Thanks all.