Rear end question........

Hey guy's. I will try to make this as short as possible:
Last August I took my 2009 GT500 to my local Ford dealer to have some rear suspension upgrades installed (upper and lowers, Eibach springs) and 3:73 gears installed. I bought my car brand new in 09 and have been wanting 3:73 gears since day one, basically just to make the car easier to drive around town. I feel like the 3:31's make you slip the clutch too much around town, although great for the highway. Anyway, my car was just an upper pulley, CAI, & Lund tune 7400 mile car with 0 issues. I had FMS 3:73 gears that I had bought for another Cobra I had back in 2004 still in the box brand new. So after I had the suspension and gears installed I was very happy, loved the lowered look, no more wheel hop and a pretty quiet 3:73 gear. I was loving life for about 200 miles, and then I drove through a parking lot one day and heard a noise that sounded like my brakes were sticking! Hard to describe but think of the noise a semi would make when doing fairly hard braking coming to a stop, sort of a high pitched groaning noise. So after further investigation, my left rear brakes are getting hot (about 25 degrees hotter than the right side, I used a temp. gun) after just a short drive. So after taking it back to the dealer 6 times and replacing the brake line, caliper, brake pads and the rotor.................. guess what? Yep still the same thing, brakes getting hot and making that irritating noise after being driven only about 10 miles. I had replaced the line and caliper late last summer early fall, but it failed to resolve the issue, so I put new pads and the rotor on it over the winter while in storage. So......... keep in mind that this car did not have a problem unit after the gear install, so I am really baffled as to what it could be??! The only thing I can think of is maybe a sensor or a bearing in the rear end??? Oh and I have the emergency brake on the left side unhooked just to be sure that was not causing the issue. Any ideas or suggestions??? After spending over $2,000 dollars for parts and install at this dealer they don't seem like they want to help or have any idea!?? The tech that done the install was highly recommended and just says there is nothing he can find wrong. Please help!

LOL, you took it to a dealer and they can't fix this??? That is ludicrous.

I owned two service stations and have probably done thousands of brake jobs over the years. What u r describing should be basic troubleshooting. You've already temp'd it, which would have been my first recommendation, so you've located the 'trouble' area. Now you just gotta isolate the issue.

I would jack up the vehicle and try rotating that wheel by hand. It 'should' be stiff, but if it isn't, drive around (locally) until the trouble (or heat) starts, then come back and jack up that corner again and try rotating the wheel.

If the wheel is stiff, I think I'd first try cracking the bleeder just a little to see if there's any line pressure. If fluid drips out, that's OK, but if it flies out and then slows, and the wheels frees up, then there's your issue, likely ABS or line related.

If fluid pressure seems normal and the wheel is still stuck, start removing parts until it rotates somewhat freely. You have posi rear end, so it will not rotate completely free, there will always be some drag (from the other side). Once you get the offending part removed, you can now carefully examine the part(s) and determine what's causing the issue.

It might be best to remove the driveshaft for these tests while jacked up, not 100% necessary, but it eliminates one more thing and should let you rotate easier by hand.

I will add that I have seen some remarkably poor work done by all kinds of techs, even the so-called good ones, so your issue could be something VERY basic (which I suspect).

If you were around me, I'd put your car up on my lift and we'd have that sucker fixed - GUARANTEED (unless it's an ABS issue, which dealer should have seen).

Good luck

Thank you Mojo88! I tried to be brief lol That is basically why I replaced all those "easy" parts myself, to just basically get the dealer to dig a little deeper into the issue. I basically said to them I replaced the caliper, then they said well it may be the hose. So I replaced the hose and then they said well we don't really see anything wrong. So for my piece of mind and to be able to say that everything that I can replace has been replaced. I will try to get it back over to them in the next week or two but I just think they will say there is nothing wrong. It is not rocket science, I told them that the 8.8 rear has been in service for 30 years now. That is why I think it may be the outer bearing or a sensor issue!???

Did you replace and grease the brake pad slides? OEM rear brake pads come with new slides. Mine were worn and indented and my right rear brake was hanging up after hard braking. Took me a while to find the cause, but that fixed mine.

Yes, I did replace those with new ones SCGallo even though my original ones looked fine, just a little dusty lol

One possibility is a sticking caliper piston on the side that's getting hot. If that side is binding when you put it on a lift, you may want to rebuild that caliper. Ford has used phenolic caliper pistons over the years and they're notorious for sticking. If they are phenolic, replace them with stainless. Ford also uses a hokey parking brake mechanism that may be binding.

007jerry said:

......That is why I think it may be the outer bearing or a sensor issue!???

Click to expand...

I honestly don't see how it could be either of those, but it's always wise to keep an open mind.

When looking at something like this, I like to utilize the old "Occam's Razor" principle, which is a line of reasoning that says the simplest answer is most often correct. Since the problem began after the new gears were installed, then I suspect something was re-assembled incorrectly. This is why I would remove one piece at a time and see when the wheel starts rotating freely. Once you locate the 'trouble' piece, then it should be easy fix. As you note, this 8.8 assembly has been around for a long time, it's not a freakin' Indy car for Gawd's sake, LOL!

I bought my current 'toy' (2010 Roush Mustang) from a forum member here (a great guy). Like any new owner, I checked the car out thoroughly and found a few minor issues. One of those issues was the left rear brakes, which had somehow been re-installed (after rear end work) incorrectly, such that the brake pad was cockeyed. I wish I'd paid more attention to the exact problem, but I installed new pads, made sure the piston was aligned properly, and put it back together. It's been perfect ever since. It's odd that this would happen to left rear on my car AND on your car????????????

Please keep us posted...... Dave F.

Bent axle possibly just on one side
-J