My 2.2 automatic (180K miles) is making a noticeable thump when medium/hard braking occurs.  If I apply the brakes slowly or ease into a stop light, nothing happens.  Also notice it when it roll slowly over a speed bump.  Feels like its under the front floorboard, also feel a jolt to the steering wheel.  It accelerates fines, nothing noticeable.  Also seems fine when shifting from park to drive/reverse.

 

Have replaced (within the last 20K miles) both axles, calipers, pad, rotors, ball joints

 

got the wheels off the ground and tried to wiggle the tires and check for play---nothing.  Tried to muscle the engine around and see if it would move--nothing.  Push down on the front to see if the struts would respond.  Nothing obvious..

 

Not really sure how to diagnose motor/transmission mounts. 

 

Appreciate any ideas from the group.  Thanks!

Think I might have figured this out but wanted to run by the group.  Got under the car again this morning and took these pics of the passenger side.  In looking at the control arm bushing, it appears from the shiny parts near the bolt heads that the assembly has shifted.

 

Also noticed a rub mark on the inner fender well presumably from the tire on a right hand turn. 

 

Driver side has neither of these type clues/indications. 

 

Control arm bushing failure?

The bushing looks bad, but what concerns me more is the fact that it's all grimy except right around the bolt heads. It looks like the bolts are loose letting the bushing slide back and forth. That would undoubtedly cause a clunking and should be fixed immediately. At least tighten the bolts up!

Replacing that bushing isn't really very hard, just kind of annoying.

 

The second picture is blurry and I can't see what's going on, but it looks like there's a section of frame rail that's been sanded down to bare metal through the paint and primer... What's up with that?

thanks.  I thought the same thing so I put a socket on the bolts.  They are not loose, in fact they are quite tight.  You are right about the frame rail, only nobody's been in there sanding.  My guess is the tire is rubbing on that spot upon full right turns. 

 

My son is home from college with the car and other than a clunk when going over a bump, he hasn't noticed anything.  I drove it for a few miles and knew something was up.

looks like that control arm bracket shifted - you're positive those two bolts were tight?

 

sway bar end links and bushings?

Yep, they are.  Just put a 1/2 inch breaker bar on them.  Couldn't tighten them at all.  Same for the other bushing a sway bar...all snug.

 

Maybe he hit something.. funny it drives fine.  alignment is good, nothing noticeable upon acceleration.  Got it up to 65 mph and couldn't tell anything.  Just when I pulse on brakes, feels like something hitting the underside of the car. 

Have you checked the caliper bracket bolts, caliper bolts, and the pads?  If they have been replaced recently, they could have loosened up.  I've seen it happen many times and it creates the same kind of symptom you are experiencing.

Thanks.  They've (pads/calipers/hoses/rotors) been replaced, probably 18 months ago.  About 1/2 the material is still left on the pads.  Checked the caliper bolts on both sides and they were all tight. 

Think I'll buy the bushing/bracket and see if that solves it.  I'm assuming I should also change the corresponding bushing on the driver side as well?

 

Does the control arm have to come out of the car to change this?

Can you loosen those bracket bolts? They may be frozen in place, but not tight enough to hold the bracket tightly to the "frame" rail.

I'd probably do both sides. If one went bad the other probably isn't too far behind. You can do it without removing the control arm. Remove the 19mm nut first, it's a wicked bugger on there super tight, then remove the bolts that hold the bracket. In your case, I'd pull one out and take a good look at it, make sure the threads aren't messed up or anything. You have something weird  going on with that bracket.
 

Think I'll buy the bushing/bracket and see if that solves it.  I'm assuming I should also change the corresponding bushing on the driver side as well?
 
Does the control arm have to come out of the car to change this?

 

EDIT: As I was closing my laptop I thought do add you should clean the threads at the end of the control arm really well. Where that big nut is. It's a lot easier to remove a nut when the threads aren't all grungy. You also have a lot better chance at not stripping it out.

Edited December 21, 201510 yr by 987687

I've also seen the backing plate loosen, causing a clunk on hard braking.

I couldn't get to that nut with anything substantial enough to break it loose, so I pulled the control arm  Take a look at the bushing in the pics below.. pretty hammered.  Still don't understand how the bracket moved. 

 

Anyway, I don't have a press to push out the smaller bushing. Is that one critical to replace?

You can just replace that whole assembly. Careful putting it back on, that mount looks symmetrical but it isn't.

Yes, I'm going to get that entire assembly (bracket and bushing).  I was asking about the other,  smaller bushing in the control arm.  The one towards the front of the car.

Oh sorry, the front bushing usually doesn't cause as many issues as the back bushing. If it's in good shape you're probably fine putting it back together as is. And as always when installing bushings, don't torque them down when the suspension is in full droop. Jack the control arm up to ride height or drive it up on ramps then tighten the bolts down the rest of the way.