Now I've Got A Clunk?!

[motorhead]

I just finished replacing the rear suspension in my Buick. It went from South Side Machine lift bars (don't ask, they were in the car when I bought it) and an ATR swaybar to UMI Rotojoint/Poly LCAs and no sway bar (Hellwig 55809 on order). The only constants are the single adjustable UCAs (rod ends on the frame side, factory rubber n the diff). There was no elongation in any of the bolt holes and no cracks in the torque boxes.

And believe it or not the car has developed a horrible clunking (almost crunching chatter) sound under braking at low speeds and over uneven pavement. You can feel it in the floor boards.

The UMI LCAs were torqued to spec under a loaded suspension (front to rear) and the UCAs were torqued as close to ride height as possible (springs had to be left out for the tools to fit). The only notable change made (other than dumping the SSM bars) was that I shortened the UCAs by 1/4" (11" total length CL to CL) in order to adjust the pinion angle (currently set at -2*).

I am going to "nut and bolt" the suspension (again) to validate my work. Also, it should be noted that the 4" exhaust is hitting the axle tube under compression... I had my wife jump up and down in the trunk to ID this problem; much to her embarrassment.

Any insight or direction would be appreciated.

 

[Silver Fox]

I just finished replacing the rear suspension in my Buick. It went from South Side Machine lift bars (don't ask, they were in the car when I bought it) and an ATR swaybar to UMI Rotojoint/Poly LCAs and no sway bar (Hellwig 55809 on order). The only constants are the single adjustable UCAs (rod ends on the frame side, factory rubber n the diff). There was no elongation in any of the bolt holes and no cracks in the torque boxes.

And believe it or not the car has developed a horrible clunking (almost crunching chatter) sound under braking at low speeds and over uneven pavement. You can feel it in the floor boards.

The UMI LCAs were torqued to spec under a loaded suspension (front to rear) and the UCAs were torqued as close to ride height as possible (springs had to be left out for the tools to fit). The only notable change made (other than dumping the SSM bars) was that I shortened the UCAs by 1/4" (11" total length CL to CL) in order to adjust the pinion angle (currently set at -2*).

I am going to "nut and bolt" the suspension (again) to validate my work. Also, it should be noted that the 4" exhaust is hitting the axle tube under compression... I had my wife jump up and down in the trunk to ID this problem; much to her embarrassment.

Any insight or direction would be appreciated.

Mike - I won't be much help here, other than to say you might want to google the rotojoint and clunking noises. I researched getting them a while back and seem to recall some people had the noise and some didn't. I hope you can get it cleared up. Let us know how the Hellwig bar works out for you when you get it.

I hope it turns out to be something loose and you get it cleared up.

Rob

 

[jdpolzin]

OK, start with this before you undo anything and report back. Put the car in reverse and feather into the gas, then hit the brakes farely hard.

Then, while holding the brake still, put the car in Drive and just bump the gas. Listen for a clunk.



Then feather into the gas again while moving forward and hit the brakes. Then go in reverse and listen for a clunk.



Let me know what happens. ------Jeremy

 

[motorhead]

Rob,

I just google it and all I have to say is: Holy Crap!

OK, start with this before you undo anything and report back.

...

Let me know what happens. ------Jeremy

Jeremy,

Will do. It is too wet to do this right now tomorrow or Friday (most likely) will be a better bet.

Thanks!

 

[scot w.]

Do you happen to have the spanner wrench for the Roto-Joints? If so, try using the spanner wrench to tighten the adjusting ring applying more pressure to the delrin inside.


Scot W.

 

[VIN7]

Mike,

When you get your Hellwig bar let me know if your end links were too long.

I had to cut about 2" of threads off of mine in order to the bar to sit parallel at ride height. I literally cannot go any shorter, but I don't expect to have to.

Besides that and some minor trimming of the axle mounting pads to fit with my Hooker exhaust it is a nice bar for the dollars.

Thanks,
Mike

 

[motorhead]

When you get your Hellwig bar let me know if your end links were too long.

I had to cut about 2" of threads off of mine in order to the bar to sit parallel at ride height. I literally cannot go any shorter, but I don't expect to have to.

Besides that and some minor trimming of the axle mounting pads to fit with my Hooker exhaust it is a nice bar for the dollars.

Will do.

Can you post some pics in the "rear sway bar" (http://www.turbobuick.com/forums/brakes-suspensions-tires-wheels/336206-rear-sway-bar.html) thread showing the issues?

I am sure I'll have a blast working around my 4" exhaust.

 

[Silver Fox]

Rob,

I just google it and all I have to say is: Holy Crap!

Thanks!

Sorry Mike. I hope it works out for you. You still serving? I retired about 1.5 years ago, and am back doing the civil servant gig now.

Rob

 

[83hurstguy]

I had rod ends make some clunking in the UCA's after they got about 5k miles on them... also got some buzzing. Yanked them and put the UMI roto-joints in there, quiet so far, but now that I googled that...

 

[motorhead]

Sorry Mike. I hope it works out for you. You still serving? I retired about 1.5 years ago, and am back doing the civil servant gig now.

Yeah I am still serving, in fact I just crested 6 yrs in January; I have to maintain that love/hate relationship with the Infantry until I can collect a fat pension and priority loading for a government job.

I've got leave for the next 3 days so it is time to spin some wrenches!

 

[motorhead]

OK, start with this before you undo anything and report back. Put the car in reverse and feather into the gas, then hit the brakes farely hard.

Then, while holding the brake still, put the car in Drive and just bump the gas. Listen for a clunk.

Nothing unusual.

Then feather into the gas again while moving forward and hit the brakes.

GRIND GRIND GRIND CLUNK CLUNK...

Then go in reverse and listen for a clunk.

Nothing unusual.

The car is up in the air and I am going to start nosing around.

 

[Browndog]

Mike, you hit any of the Ottawa cruise nights in the summer?

 

[motorhead]

Actually, kinda sorta?

Last year we didn't get moved into our new house until August... so we caught the tail end of the Rockland cruise nights (and it was total fluke that we found it). Personally, I am not much of a cruise night fantatic. I hate the music and I hate strange people without a concept of personal space touching my car.

I'd rather go racing.

 

[jdpolzin]

Nothing unusual.



GRIND GRIND GRIND CLUNK CLUNK...



Nothing unusual.

The car is up in the air and I am going to start nosing around.

OK, well not good. I know you mentioned that you didnt notice any damage from the SouthSide bars but did you double check the holes on the frame side of the front mounts (on the frame) of the lower control arms? A lot of times the Southsides will wobble the holes on the frame side. They usually dont wobble the tab holes (inner tabs, front mounts, lower control arms), so it's not always completely noticeable. I do agree with Scott and double check your tightness on the joint. But, most companies will preset the load before they let them leave the factory so just be sure to check the un-obvious before making any adjustments that may throw you a curve later on (snowball effect). Give it a once over and I'm sure you'll get er figured out! ----Jeremy

 

[Browndog]

Actually, kinda sorta?

Last year we didn't get moved into our new house until August... so we caught the tail end of the Rockland cruise nights (and it was total fluke that we found it). Personally, I am not much of a cruise night fantatic. I hate the music and I hate strange people without a concept of personal space touching my car.

I'd rather go racing.

That's pretty much my philosophy. Just curious as I'd like to see your car some time.

 

[motorhead]

OK, well not good.

Agreed.

I know you mentioned that you didnt notice any damage from the SouthSide bars but did you double check the holes on the frame side of the front mounts (on the frame) of the lower control arms? A lot of times the Southsides will wobble the holes on the frame side. They usually dont wobble the tab holes (inner tabs, front mounts, lower control arms), so it's not always completely noticeable.

The holes are okay. The DS upper plate had the weld cracked clean, I didn't see it until I got out my prybar. I just welded the sh*t out of it; it should hold. Nothing quite like welding next to your fuel lines to get your blood pumping.

I do agree with Scott and double check your tightness on the joint. But, most companies will preset the load before they let them leave the factory

Tighter than a nun's youknowwhat on Christmas...

so just be sure to check the un-obvious before making any adjustments that may throw you a curve later on (snowball effect). Give it a once over and I'm sure you'll get er figured out!

I retorqued everything to 100ft/lbs. Originally I had done them to 72ft/lbs per UMI's instructions. We'll see if that helps.

I have to install some Bilsteins in the front and modify the dust caps before I put it back on the ground. We'll see if any of this helped.

Thanks for the help guys.

 

[scot w.]

I do agree with Scott and double check your tightness on the joint. But, most companies will preset the load before they let them leave the factory ----Jeremy

The only reason I mentioned that is just because "it's new" doesn't mean that it was quality inspected properly, sometimes stuff slips by and they could have been loose. It was worth checking! Time to move onto the next possibility..

Scot W.

 

[chopped39]

The holes are okay. The DS upper plate had the weld cracked clean, I didn't see it until I got out my prybar. I just welded the sh*t out of it; it should hold. Nothing quite like welding next to your fuel lines to get your blood pumping.

There are companys that make reinforcements that fit in by the upper arms and lower braces also

 

[jdpolzin]

The only reason I mentioned that is just because "it's new" doesn't mean that it was quality inspected properly, sometimes stuff slips by and they could have been loose. It was worth checking! Time to move onto the next possibility..

Scot W.

Agreed!

 

[jdpolzin]

Agreed.



The holes are okay. The DS upper plate had the weld cracked clean, I didn't see it until I got out my prybar. I just welded the sh*t out of it; it should hold. Nothing quite like welding next to your fuel lines to get your blood pumping.



Tighter than a nun's youknowwhat on Christmas...



I retorqued everything to 100ft/lbs. Originally I had done them to 72ft/lbs per UMI's instructions. We'll see if that helps.

I have to install some Bilsteins in the front and modify the dust caps before I put it back on the ground. We'll see if any of this helped.

Thanks for the help guys.

Glad you found that crack!! What I was trying to do is put the load in the front of the car (driving backwards and hitting the brakes) so once you pull forward, you will see where the car wants to put the load to (the noise)! I had a heck of a time with SouthSides on a car that slightly wobbled inside hole. I ended up re-welding the hole and drilling it back out, then i welded some support washers to support it. It was a pain in the butt finding that one!

Well, good luck with it and glad you found the crack!!! -----Jeremy