I have a 98 GT that thumps at low speed (0-25 mph) but I do not notice at driving speed. I notice it when braking especially at low speed? Any ideas, the tires look good. Could it be a wheel bearing or ball joing causing the thump? I am going to rotate my tires and see if it follows.

I just got the car and don't know anything about it yet. Just don't want to have a wheel fly off going down the road!!!

 

Could be alot of things. Worn out sway bar, end link, control arm or strut mount bushings are the most common causes. If all those look OK, jack the front end up so the wheels are off the ground. Grab the wheel with both hands and wiggle it back and forth. Depending on what directions cause it to move you could have bad inner or outer tie rod, upper or lower ball joint(s) or a bad wheel bearing.

Good luck...

 

Ok, so I rotated my tires to find it got worse!!! My drivers side is reverse cupping the inside?? When I say reverse, it is wearing the front of the inside tread more than the rear of the tread? Make sense?? Passenger side is kind of ok?? What could be the culprit?? I am going to be going thru the front end this winter, but my thought is shocks?? 120k on stock shocks is not good.

The tires are where the rumble or thump is coming from though!!!!

 

Borrow a set of wheels/tires from another Mustang.

 

I had a car with a similar noise, I checked everything. Finally after a few months, I noticed a rear tire developing what looked like a bald spot, while the rest of the tread was good. I replaced that tire, and thumping went away.

 

What could be causing this on one side?? Bad shock or ball joint?