Diagnosing Suspension Noise in 2010 Mustang


#1

The problem:
Every time my front end goes over a bump, or I encounter a less than ideal road, I hear and feel a small knock coming from my front suspension. This knock can be felt in the gas and brake pedals, as well as if my foot is off of the pedal. It seems to be some part of my suspension transferring the impact to my frame.
Diagnosis so far:
I checked my brake calipers because I recently did a brake job, to make sure they weren’t knocking around. They seem to be mounted correctly.
I checked my front sway bar bushing and end links by using a pry bar. They wouldn’t budge.
I’ve visually inspected my struts and control arm bushings. Still nothing obvious that could be causing it.
Does anybody have any idea what could be causing this issue, or have any time to take a look at it if I put it on the lift?

Thanks!


#2

I’m trying to remember the exact bit that was involved when I had a similar problem in a totally different vehicle. I’d just had some work done, so I took it back to the mechanic when I was hearing a clunk in bumpy conditions. For my 1979 Dodge Aspen, I believe it was the sway-bar. It only happens under bumpy conditions because the frame gets torqued just a bit, causing it to hit the sway-bar. Certainly for my car, it was nothing repairable, nor did it cause any damage. It never got any worse…


#3

This could be a mount in the drivetrain(the usual suspect in many rear wheel drive vehicles is the transmission mount).


#4

The plot thickens. I ran an OBD-2 code check and got a C1963, which seems to indicate that the AdvanceTrac is off due to a faulty connection with the Steering Wheel Angle Sensor. My steering has been kind of loose after an alignment I got about a year ago, so it might be unrelated. But traction control not working properly can definitely affect the quality of the ride. Not sure that would cause knocking though.


#5

Did the "knock occur before or after your recent brake job?

That code is related to a few items which are then tied to a few driving variables that need to be met in order to reset that particular code if all is “normal” after a typical repair like an alignment, brake repair etc.
One often overlooked issue is the car’s battery condition. A low voltage or low output from the alternator - poor charging can also trigger this code.
Another one of those items that C1963 is related to is the ABS system (anti lock brake & stability control system - ford’s AdvanceTrac in this case, (Mercedes, bmw and just about every every car make inserts their own title for it here)

I’d suggest starting with checking things like - the cleanliness of the abs sensors at the wheels that you did the brake job on.
Dirty sensors can cause the ABS to deploy braking pressure to a wheel.
Erroneous inputs to the ABS controller can cause decreased engine performance.


#6

Did the "knock occur before or after your recent brake job?

It is difficult to say whether the knocking was occurring before then. First, my brakes were botched by a shop that put them in sideways when I was going out of town, then I replaced my rotors (that had been covered in anti-seize to hide the botched job) and fixed their bad work. Then, (probably due to being over-torqued), my rear-left caliper bracket bolt sheared off and I had to jack it up and put a new OEM one in. This all happened in a matter of days. I don’t recall any major knocks before the botched brake job, but I also am now paranoid about noises coming from my car, so it could just be I wasn’t looking for it.

One often overlooked issue is the car’s battery condition.

I had just remounted the battery in this car before that code threw. I cleared the code, so if it returns, I can be sure it is a consistent issue and not just due to me removing the battery.

I’d suggest starting with checking things like - the cleanliness of the abs sensors at the wheels that you did the brake job on.

The brakes are actually working fine, but I will be removing them all soon and cleaning them with brake cleaner, so if that solves part of the problem I’ll let you know. However, I don’t see how the brakes deploying would cause frame knocking.

This could be a mount in the drivetrain(the usual suspect in many rear wheel drive vehicles is the transmission mount).

Wouldn’t a poor transmission mount cause the car to shake regardless of whether it was going over a bump?


#7

yes.

A broken trans mount on a rear wheel drive car like your mustang with cause quite a knock or thump - no bump needed.

Also - what do you mean by “the brakes were put in sideways” ?

Anti-seize used sparingly on the rotor to hub mounting face is a good practice.

Is there and evening that you are available ? not tonight tho


#8

Also - what do you mean by “the brakes were put in sideways” ?

They mounted my brake pads in at an angle, with the metal pins stuck outside of the caliper, causing them to carve away at my poor rotors. They put anti-seize on the actual brake pads and on the rotor face, not just the mounting face. It was a mess. When I finally got it up on a lift to inspect, my rotors were warped beyond repair. So I bought a new set, sanded the anti-seize off my pads, then reinstalled them properly.

Is there and evening that you are available ? not tonight tho

I will be coming in tonight to do the aforementioned cleaning, but if my problem isn’t solved by doing that (I suspect it wont be), I will be coming back in Sunday (if the lift isn’t too occupied).


#9

i can meet you sunday sometime.


#10

Okay, how does 1pm sound?


#11

Not sure what you look like or how to contact you, but let me know if you’re gonna be in today. I’m at the space.


#12

I cannot make it down there until later this evening.
What model and engine is your mustang.
Gt, 6cyl, 8cyl etc?


#13

It’s a v6. Another member took a look at it with me. He thinks it is worn struts, but he also pointed out some torn boots on the tie rods that I didn’t notice. Also there is a broken grommet on the right control arm (although that likely isn’t making the noise). So I think next step with be new struts and shocks. Thanks for the offer to look at it though.


#14

I got tied up in family things yesterday with elderly relatives.

Family first.

I can meet one evening later this week (not thurs that is tour night) if you want.