Ok so I installed a larger rear sway bar about 1500 miles ago.

About a week ago I noticed a fairly loud clunk when running over a bump.

Over the past week I have been trying to pin down exactly what is causing the noise.

I have put the MINI on my lift and took off the wheels put I can't see any paint that his chipped off where this is metal on metal contact.

The clunk is fairly random but I can always reproduct it in two ways. When I take a left turn to go up my very steep driveway there is a very loud clunk. When I take a right to go up my driveway there is no clunk or if there is clunk it is too soft to hear.

If I make a very sharp left hand turn, a U-turn pretty much always does it, there is a loud clunk as well.

Sometimes if I hit a decent sized pothole with the left rear tire there is a clunk but not always.

So what part of the suspension is hitting where do you think?

I checked all the bolts when I had the car up on the left and I couldn't find any that were loose.

 

Did you install the sway bar while the car was on a lift? If so, drive the car onto a pair of ramps or alignment rack and remove and reinstall the bar. There should never be any pre-load on the bar - unintentional preload. This can occur if a bar is installed while the suspension is in full droop. If you installed the bar in this fashion, you may have created the above condition. You may also get some unpredictable handling characteristics.

Bars should be installed with the full weight of the car on the wheels.

 

Did you change springs at all? Perhaps your left strut top nut (on the
piston shaft) is loose? might not be anything to do with the
swaybar...


You retorqued all subframe bolts too, right?

 

Was it a Madness 2 hole swaybar by any chance?

 

This doesn't make any sence to me and I might disagree with this statement. Can you enlighten me meb?

 

Axwed,

Do make sure the sub frame was bolted back up tightly. Sounds to me that it may be loose.


ooops, looks like kenchan already mentioned this, along with a good suggestion about the rear shock. Since one shock has to be removed to install the bar, this could be a possibility.

 

I was taught to install sway bars while the full weight of the car is on all four wheels. This information appears in a couple of books as well - unfortunately I cannot remember which ones - I'm old How To Make Your Car Handle may be one...I'll dust it off if I can find it. The potential for pre-loading the bar exists and this may be influenced by sway bar design too. When ever I've intalled a bar, I've followed this procedure. In fact, I always set the sway bar end links/hime joints a bit loose so that the bar is not working or loading up as the suspension absorbs little inputs from bumps or road irregularities ( this is also a noisy proposition). I want the bar to work very progressively as I turn into a turn, to 'come-on-line' when I ask it to. I'm getting off topic, sorry.

The procedure eliminates potential binding or pre-loading. It is a procedure followed by a number of very reputable shops I've had the pleasure of working with.

Onasled, Unfortunately I cannot eloborate from a physics perspective. And, this procedure may be a response to eliminate problems with 'some' sway bar designs. Since this procedure won't hurt anything, I follow it religiously. I have seen a few cars become a little squirely at full boil on the track reportedly from improper swaybar installation. Maybe jlm or Andy can chime in??? Or perhaps your physics back ground is better than mine...I actually don't have a physics background. But, I did sleep at a Holiday Inn last night.

 

Maybe if you are using adjustable links or if the bar is one like Minimania with sliding link points. Otherwise installing a standard swaybar with hole selection will not have any preload at all. No?

 

Actuallly, stock end links can contribute to preload. The links themsleves can become preloaded. Adjustable end links or hime joints are designed to remove any pre-load from the links or bars allowing the bars to work free from preload.

I wish I could remember more about this Onaslad. It's a little embarrassing to throw something like this 'out there' without having the correct words to back it up. I'm pretty confident, however. Give me a little time and I'll try to find the reasoning - by Monday for sure. Sorry about this.

The above points to why I selected the signature below...

 

I torqued the subframe down to 75 nms using my shops 400 some dollar mac tools torqure wrench. I am pretty confident it is accurate.

I used an impact gun to put on the lower 21 mm bolts on the struts and an air rachet for everything else. I checked just about every bolt when I had the car up on the lift the other day and everything was tight.

Someone explain to me how you install the rear sway bar in the mini without having the car up on a lift?

None of the instructions or how to's i read on NAM mentioin anything about lowering the car before final instilation. I don't even see how you could get a wrench in to tighten either the end links or the sway bar to frame mounts when the tires are on and the MINI is sitting down.

The bar is a 3 position bar with the aluminium clamps to keep it from sliding back and forth.

 

I've never tried this with a Mini yet, but it wasn't even close to easy with any other car. You'll need an alignment rack or ramps, and perhaps the aid of a contortionist.

Keep in mind the location and position of the swaybar end links; imagine what a link half the stock length would do for handling... Not to be confused with how close or far away the link is from the end of the bar. In other words, is the bar end parallel with the road? Or is it pointing up or down with respect to the road?

By the way, the same installation technique holds true when reinstalling suspension control arms or any other suspension component that incorporates bushings, links or otherwise; final torque settings or tightening must be done while the full weight of the car is on all four wheels. This is also very difficult, but very proper. Otherwise things bind and tear - this actually appears as a warning in many shop manuals. FYI

 

I don't know meb??

 

This is a time when being a scientist might help me to explain myself.
I'll get some supporting infor so I don't leave you good kind folk in the dark. It's just been a long time since I've turned wrenches every weekend at a local event or track.

Be patient, I mean to help, not hinder. Where is Spoc when you need him?

 

It's always a good idea to torque down the nuts and bolts that hold
the suspension together to the car while there is weight on them so
that it is close to its natural state as much as possible. metals and
rubber/plastic materials bend, compress, twist, pull, etc. while they
are torqued down so it is always a good idea to try to simulate is
neutral or kind of this 'default' state.

I think what meb means is that after you install the bar and ready to
put the rear struts back in its position along with endlinks to the bar,
place some weight on the strut and endlinks/bar by jacking up the
arms and compress the suspension before you torque down
everything.

Im no doc nor scientist...just going by reading instructions and
by personal experience. :smile:

 

The real strange thing is that this clunk did not present itself until a couple of weeks after I put the bar on. During this time I took a 1000 plus mile road trip to CT and back.

I could see putting all the susepnsion bolts on snuggly and then lowering the car down and putting some weight on the suspension to torque everything.

I just don't see how you could torque the end links on the MINI with the wheels in place since you need to put a wrench and a alan wrench in there to do it. I would have to go an look but I dont' think it would be possible at all to tighten the swaybar to frame links with the wheels on at all.

Your only option would be to just put a little bit of load onto the suspension with the wheels off. I could do this by butting some wooden blocks under the rear suspension then lowering the car on the lift some till the suspension contacts the blocks.

 

Yes, I meant while the wheels are off, ofcourse. Not on a ramp. That is
why I mentioned to use a jackup the arm to compress the sus.

I have a feeling that the rear strut top bolt on the piston is loose...
did you change springs at all?

 

When my bar was making a popping noise the problem was the bottom bolt of the link, it came loose after a week or so and I had to torque it again.

 

A few months ago I went threw the same problem. Going over speed bumps it made a rather annoying poping noise. Turned out to be the top bolts on the endlinks. Be sure to check them closely. I over looked them several times while trying to diagnose the problem.

 

Drove a Volvo 544 (a long time ago) that clunked under similar conditions. One of the bushings was shot. Could a bushing have been left off or worked its way loose?

 

I did not change the springs. I took off both struts though to get the sway bar in and out.

I will go back and check the end link bolts again to see if maybe they worked loose some.

I did some more research on the clunking tonight.

During left hand turns there is a loud clunk even if the turn is not that tight. Right hand turns almost never cause the clunk even if they are very tight hard turns.
Running over a bump with the drivers side wheel causes a clunk even with light bumps. Running over the same bump with the passenger side wheel normaly does not cause a clunk.

 

Check to make sure that the sway bar can not "float" left or right under load. Just saw one installed that had "floated" all the way to the drivers side. Did not have any stops built in on the bar to stop it from sliding sideways. It was hitting the springs on the passenger side.

 

I have the aluminium clamps on with the alan bolts installed on the bar.

Don't see how it can be sliding to the drivers side.

 

Check it anyway.....could be the simple fix.

 

I guess you can undo the swaybar from the endlink and drive slowly in an open lot to see if you still get the noise. Atleast if you do you know it is not the swaybar causing it. Process of elimination...

 

Ok so today I put the MINI back on my lift rechecked all the bolts and nothing is loose.

I loosened the sway bar to frame bolts and the aluminium clamps and double checked the centering of the bar. I think the bar was a little to the drivers side by my measurment so I gently tapped it more towards the center with a dead blow plastic mallet.

I lowred the MINI some onto wooden blocks and preloaded the suspension as much as i could then retightented the bolts. I think the bar was making contact with the driver side spring. I can see some light scraping marks on the spring. I put some yellow tamper seal on the place and will check it again in a few days.

So far I have not hear any loud clunking since doing this just normal bump clunks.