Mystery knock

**mrpontiac80** · 05-20-2011, 03:22 PM

OK guys, you nailed my last problem so hopefully this one happens the same way.

Ive got a knock coming from the front end of my car as I drive. Seriously sounds as if someone is knocking on the floor or inner wheel well. Here are the symptoms...

Knock at all speeds.
Knock speeds up and slows down in relation to speed traveled.
If I turn the steering wheel just enough to veer slightly off center the noise goes away or gets real quiet. If I turn anything more or straighten up the car, the knock comes back.
If I ease into the brakes, the knock is still there but slows with the car.
If I press firmly onto the brakes, the knock goes away.

I replaced my wheels and tires yesterday with used WS6 rims and the vibration that I was sure was coming from the crap tires went away. Although I think the knock was always there to some extent, got very loud and noticable while driving it last night. In fact, my first thought was to pull over and check the lug nuts. I did and they were fine.

I feel this is something related to the brakes, rotors or etc. Right now the brakes work fine and look to have some life left. The rotors look fine too but are on my to replace list when I do brakes in the future.

I feel my shocks also could use replacment and will do this when I can too.

So anyone want to take a stab at the symptoms and tell me where to start? Whatever it is, is starting to really get obnoxios and like I said, it felt bad enough in the steering and noise that I thought it could be loose lug nuts but it was not.

Thanks in advance guys.

**cammed goat** · 05-20-2011, 03:26 PM

Could be:

Lower ball joint
Possible broken strut mount
Lower control arm bushing worn out
Stabilizer link broken
Rotor causing "kickback"-rotor contacting pads and knocking pads around in caliper
Worn hub/bearing

**mrpontiac80** · 05-20-2011, 04:26 PM

It will likely be a couple of days before I can crawl under and take a look since its pouring rain here. But I am definatly gonna check all the areas you guys are thinking.

I did score a complete revised 3 volume set of 1998 GM service manuals from ebay for only 25 bucks though so it looks like I can put them to use when they get here.

On a side note, I don't have to drive the car since its just a toy, but the recomendation would be to let it sit untill fixed right? I really don't want to damage anything worse than could allready be.

**cammed goat** · 05-20-2011, 04:52 PM

Agree. Don't drive it until the problem is fixed.

**pajeff02** · 05-20-2011, 05:19 PM

Agree with all stated. When you get the car in the air, grab ahold of each tire and try to wiggle it side to side and then move your hands and try to wiggle it up and down. If you feel any sort of play you know you have an issue with side to side you probably have a tie rod issue. Up and down movement would most likely be a ball joint, and movement in both directions is probably a wheel bearing.

Looks the inside of your rims over and see if you have any scrub marks from the rim impacting something. Pay close attention to any wheel weights and the area of the rim that runs adjacent to the brake calipers.

**TransAmX2** · 05-23-2011, 07:25 AM

also check to see that your front rotors spin freely, once it's jacked up actually spin the wheel see if the noise is there, remove wheel and repeat and look for any wear marks or anything obvious; pad dragging on rotor and "skipping" across surface, maybe a wheel bearing going bad.

**SSnow** · 05-23-2011, 09:25 AM

Tie wrap put on your wheel? Have you crossed any of your buddies lately?

**mrpontiac80** · 05-23-2011, 02:29 PM

Well, yesterday morning I got the front end jacked up into the air to see what was going on. After checking things out, I realized it was nothing but a rookie mistake. I hate to admit it but it was loose lug nuts on the driver's front. Im talking super loose. When I said previously that I checked the lugs, I never used a lug wrench cause I had just pulled off the road to check for a loose wheel. It was solid and I drove the 2 miles to get home and parked it.

Fast forward to yesterday, car in the air and I find its loose lug nuts, I go to remove the black caps over the lugs and the lug nut comes off too. All this from about a 25 mile round trip. I knew that aluminum wheels need retorqued but....

Anyway, thanks for the troubleshooting help guys. Ive been driving it for two days now and all is good at least on this topic now. Got a lug wrench to retorque the lugs for the next few trips and hopefully that will be it on this deal.

**TransAmX2** · 05-24-2011, 11:39 AM

wow, good thing you caught it before you went further, would have been damaged rim and possibly damaged car and driver. I don't think you need to re-torque the wheels, I've rotated/ installed thousands and as long as you do the standard "star pattern" tightening (always snug up one then go to one across from it untill all are snug then tighten in the same matter) never have a problem. Only wheels i've ever seen come loose are either misinstalled in the first place or had someone messing with the car. At least you figured it out and it's a cheap fix (the best kind)