I've got this noise that sounds like a metal scrape that seems to be coming from the left rear - and it only happens when I make left turns or left curves. And even then, sometimes doesn't happen at all. I dont think this is rear brakes? Its not a typical brake squeal. I am thinking wheel bearings - do they go bad on these cars? Maybe differential? I have the standard differential unit. Has anyone else had diff problems? I'd imagine that is likely an expensive fix especially if OEM.

But the sound is sort of like scraping two metal plates together.

 

I had my pinon bearing fail last year and it was a metal scarping sound that got progressively louder , but it wasn't dependant on cornering. The rear of these cars don't have wheel bearings like the front end does , but there are bearings inside the axle that can go bad ...

 

Do they usually take it apart and replace individual bearings or sets or just replace the whole diff, pinion & bearing assy?

 

I had all of it replaced since there was metal shavings all over and I didn't want any noise noise coming from the rear end after having it fixed. I also upgraded to GT500 pinion replacement ...

 

if only when cornering one way, I'd guess just something rubbing on the brakes- the wheel bearings are straight roller, axle is held by clips in the center section, and theres normally a fair bit of axial free play- axial loads are handled by the center section bearings, if those go bad, should be noisy all the time....get both wheels off the ground, put in neutral, rotate the wheel while pushing and pulling on it- bet youll hear the sound faintly.
pop the caliper/disk off and look for rub marks on one of the rusty areas. my Mark VII had a noise that was just rust on the starwheel rubbing the abs sensor.

if the posi clutches are gone, or a bad spider gear pin/gear, noise *should* be when cornering in either direction, but not always... have you ever done a burnout that left one mark? if the posi slips for some reason(one tire wet or something) the clutches will burn quickly. I saw a carrier a buddy pulled out of his car after one of his kids did a smoky one wheel (open rear) burnout, it had melted the spider gears to the center pin... folks often dont relize in a one wheel burnout that the spinning tire is turning twice as fast as the speedometer reads, and the high speed rotation of the spider gears(plane bearings) tears them up in seconds, as they normally only rotate slightly when cornering.
the posi clutches arent all that strong- with both tires in the air and the car in low gear or park, you can usually force the wheel to rotate by hand- otherwheel will rotate backwards as clutches slip...if the posi is shot, the rotation will be easy, a new posi will take a fair bit of effort, doubt its over 100 ft/lb- two hands on the tire should do it...clutches should slip pretty quietly, if you hear noise, night want to pop the center cover, be sure there nothing coming apart in there.
I just pulled the cover off my 2000 marquis, 149,000 miles, the oil in there stinks, but was metal free and looked that clearish-green even after all those miles... I had to pop off because I backed into a curb and disturbed the cover edge and it started seeping...lots of floor jacking damagewill do the same- might be worth a quick look-see underneath for any oil staining on the bottom of the pumpkin...
if you would happen to find a wheel bearing bad, Timken makes a 'repair bearing' that has integral seal, moves the bearing out to the old seal location, I put those in my Mark VII 40k ago, cheaper than new axles (bearings ride directly on the axle- no inner ring). changing is easy- pop the spring out of the carrier, slide the clips off, slide the axle out, slide-hammer the old bearing out, tap the new one in, slide it back together...getting the center wavespring back in the carrier is a bit of fun, but not bad...be sure to add friction modifier to the oil, or clutches will stick or chatter when cornering.

 

Well, it turns out that it was the brakes. I had never heard of that kind of noise being a brake indicator and it was only turning left, not right. The tech said that it was metal to metal on the left rear but not the right. Both pads were replaced, rotors turned & cleaned up and now it sounds like new. There's 6mm thickness left on the front. Is it normal for the rears to wear out that much earlier?

 

I started hearing a slight noise coming from my rear and it turned out that the passenger side pad was worn down and it was the brake wear indicator I was hearing. They said the caliper had gotten stuck and that is why it was only on the passenger side ...

 

I may have had a stuck caliper too, since one side (left) was worn down so much. I dont think the right side was near its end. I hope the tech checked that. Don't the rear brakes usually last longer than the front on these cars? They did on my Camaro.

 

The fronts do most of the stopping , so I would think the rears would last longer. I'm wondering if the caliper sticking has to do with the parking brake system , since the rear brakes are part of it ?

 

That is a good point. I thought the front did most of the stopping, but the tech said the rear did more work because of the parking brake (?). My left caliper may indeed have gotten stuck. And I don't know if they fully fixed that or just slapped new pads on.

How would I know if my left caliper is sticking? What symptom would I have?

 

I don't see how the parking brake could make the rear brakes do more of the stopping either , unless it leaves the rear pad slightly touching the rotor even when the handle is down ? I would assume there's supposed to be a gap when the handle is down , someone correct me if I'm wrong. That's how I plan on checking to see if mine are dragging again , by sliding a feeler gauge between the pads and the rotor to see if there is a gap ...

 

The traction control affects the rear brakes. I usually turn mine off.

 

I did the traction control mod years ago , mines always off unless I turn it on ...

 

Caliper slide pins were probably dry of lubricant or moisture got past slide pin seals and started to seize. Pins should be re-lubricated with silicone brake grease when performing a brake reline.

There was also a problem with early model 05-0? mustang park cable end seal boots cracking which if not addressed would allow the cables to seize possibly in the park position and cause the pads to overheat and wear out. There was a TSB for that.

 

Thanks. The more I think about it, I think that is what happened. If the pad wore down to metal and never gave any indication, it was probably the inner pad because the wear indicator is on the outer pad. So the caliper probably stuck with more pressure on the left inner pad and it would have worn out without me knowing until it was at zero. And that would probably also explain the more wear (and then noise) when turning left.

 

I am having this exact same issue!!!

How many miles were on your car? Mine has 35k

Thanks

Jesse

 

I had about 55,000. That's too soon for rear pads. You should pull the wheel and check the pad thickness both inner and outer.