slalom noise
 

I've been having this weird "thump" coming from the front end for a while now. When I go about 30 mph and steer left to right as if I were doing a slalom I can feel and hear this light "thump" sound and I can feel it through the floor and gas pedal only. Can't feel anything through the steering.

It's not the battery or spare tire being loose, I checked those and crossed them out. Frunk is empty. I took the car to a suspension shop while I was getting an alignment and had them check and they can't figure it out either. There doesnt seem to be excessive play in the front wheels.

What in the world could it be? Wheel bearings? I have no noise from them at all but according to maintenance records they are original at 135K miles.

2000 2.7L Manual, ROW M030 suspension, original lower control arms, drop links changed 25k miles ago. The steering is still pretty tight.

Anybody has any ideas?

Thanks,

Cristian

You put the car in the air and wiggled the tires I trust.

How about motor and transmission mounts. All original. I know in the rear but sometimes the chassis transmits things and fools us.

Thanks for the answer mike!
I put a new engine and transmission mounts myself a while back so I'm good there. Just put new tires on the front and got an alignment and with the wheels in the air we checked and there was no significant play.

I recently replaced the suspension with the M030 kit and basically went through quite a bit of the front and rear components and me and my mechanic didn't notice anything out of the ordinary. I had the same issue before the swap as well so I'm counting out springs shocks and sway bars.

It does it in gear or in neutral steering both left and right

Spare or tool bag floating around in frunk?

This doesn't sound like a wheel bearing to me. Failing wheel bearings will often sound like a constant "rumbling" noise during either a right or left turn (depending on which side wheel bearing is failing).

Even if both left and right wheel bearings started to fail at the exact same time (which would be pretty rare), you would hear the rumbling move from one side to the other as the car was driven in a slalom of repeated right and left turns.

A thump sound implies that something is moving and then hitting something else which stops the movement and its moving back and forth as the car slaloms. Often suspension and steering problems are only apparent under loads, so it can be hard to find the exact problem with the suspension and steering unloaded when its up on a lift.

Timco that was my first go to so I test drove without the spare and tool kit. Could still replicate the issue.

Thom that makes sense about the wheel bearings.

Could it be some ball joint or bushing that's not tight anymore? Coffin arms are original so are the tie rods and everything on the steering rack.

Again I did check these things to the extent of my ability but as you said this only shows under high load like very hard steering, I can't feel a thing under normal driving conditions.

Honestly if I can't find the culprit I'm gonna let it be and see if it gets worse and maybe easier to diagnose. because it's such a minor nuisance I'm not going to throw parts at it.

Any ideas are welcome guys!

Thanks again,

Cristian

you might check the lower control arms. when the bushing goes bad, it starts as a thump you can hear and feel. I first noticed mine only during cornering, then on a bumpy road. It also started as only an occasional noise, then got progressively worse. If the rubber boot around the bushing is intact, some posters have been able to inject grease through the boot and have the noise go away for several months.

Excellent tip thank you! I'll check the bushings and report back.

If I do end up replacing front control arms do I need an alignment?

Binding front sway bar bushings? If you are OEM though I think.they have the fabric type of threads in the bushing which don't require any lubrication. If they got grabby, or loose and worn out, that bar could thump around a little. To check you could lift the car and pull it but it might only happen under heavy twisting (like a slalom) but you might be able to inspect the bushing with a flashlight.

If you have adjustable drop links, the bar might be hitting the lca under full compression (a stretch, I haven't really looked at the front lately)

No alignment needed when replacing LCA with like OEM parts.

I replaced the sway bar a while back when I put the M030 kit on and bushings were virtually new so that might be a long shot but while I'll have the car up I'll check those out too.

Thanks for the input Steve!

There are LOTS of moving parts up front and many will be hard to diagnose

http://image.superstreetonline.com/f...suspension.jpg

Shock top bearings??

Control arms and coffin arms would be the most suspect I think.

Don't think it's the shock top bearings because they are almost new and I had the same issue before replacing them.

So far control arms are the prime suspect.

Is there any sure way to check if they are cracked? I think I can take the to a place with a lift where the wheels are not in the air, that would be the best way right? If the wheels are in the air then what's a good way to check? I hear sticking a pry bar between the coffin arm and checking the bushing for cracks? Are any cracks/tears allowed at all meaning could they be just superficial or if see any they are done for?

It's prob about time I replace them since they are original but i only want to buy parts if I really need to.

Why don't you borrow a GoPro camera and mount it under the car or in the wheel well and take it for bumpy ride and see what you record. Perhaps you can capture the sound and at least examine the parts as they are stressed?

With 135K on the car, I'd say it's the control arms. My 2002 with 145K made similar noises, and after I rebuilt the suspension, all is now quiet and thump-free.

If you are going to have it apart enough tot replace the LCA's, you may as well replace everything else, too. Expensive, but the results will be worth it.

That's a good idea! If I can't pinpoint the issue I might resort to that, I have a gopro. It will at least make for an interesting video if nothing else :)

I'm getting there in terms of refreshing the suspension :)
LCA and tie rods are about the only original parts on the car.

Tomorrow I'm going to replace my O2 sensors and while I have the car on the lift I'll have a good poke around and see if I can confirm the LCAs are bad. I'll report back.

Thanks to all for the input!

Cheers,

Cristian

Well.. I think I had one of those "Now there's your problem.." moments when I checked my LCAs.

http://i1314.photobucket.com/albums/...pskimezq1e.jpg

http://i1314.photobucket.com/albums/...psygfyypu0.jpg

Looks like one is quite torn. I didnt take a photo of the other side but that one also showed signs of surface cracks and is probably not far behind.

I was only able to see this with the car up in the air and the suspension preloaded.

I'm getting some new LCA's to replace and will report back with the result. Hopefully this is the only culprit as I couldnt notice any play with any other parts while checking.


Thanks to all for your great feedback!

Cheers,

Cristian

Glad that you finally found it!