Vibe at 90....

[MrClean]

So after removing the Spyder, and re-installing the factory noodle (with a new crush collar and pinion seal), the vibe is still evident at 90.

Not bad...you have to have the windows up, radio off/muted, and be on a reasonably smooth road, but it's still there, albeit dampened by the noodle's rear section. I guess the poly bushings from the BRM rear sway bar and CHE UCA and panhard bar do transmit more NVH to the body than the stock bushings, because I really don't recall feeling the vibe prior to their installation.

Since the stealership's techs won't drive it above the speed limit, their installing the vibration analyzer and then calling me to drive it while one of them operates the machine....going in Monday to have this done. Hopefully the vibe originates in the pumpkin area so they'll open it, measure the round-out on the carrier, etc etc.

Just venting.....the car is a source of pleasure as I love how it looks and how it hauls with the 91Tq tune and 4.10's, but the vibe frustrates me...I feel it's unacceptable to have the vibes...am I being unreasonable to expect vibe-free operation up to ~140 mph?

 

[SoundGuyDave]

So after removing the Spyder, and re-installing the factory noodle (with a new crush collar and pinion seal), the vibe is still evident at 90.

...

Just venting.....the car is a source of pleasure as I love how it looks and how it hauls with the 91Tq tune and 4.10's, but the vibe frustrates me...I feel it's unacceptable to have the vibes...am I being unreasonable to expect vibe-free operation up to ~140 mph?

Personally, I don't think it's unreasonable at all, but a lot depends on what you're willing to do to eliminate the vibrations. Even small imbalances are magnified (logrythmically?) as the rotational speed increases. Ford will probably work with you up to 90 or so, or whatever the max speed limit is on a road that you "commonly drive," but I doubt that they'll do anything for you trying to go well into the triple-digits. If the carrier is out of round, and replacement fixes the issue, then great. If it doesn't fix the issue, you'll have to start working on EVERYTHING that rotates past the given speed... At "extreme" speeds, tiny imbalances are magnified. You'll have to start checking brake rotors, axle shafts, wheel bearing runout, to say nothing of wheel/tire to a much tighter tolerance than common. Not saying it can't be done, just that it'll take more effort, and probably more money.

Would you agree that the Spydershaft was not the culprit? Sounds that way to me! Is it going back on?

 

[MrClean]

I agree wholeheartedly that the Spyder was NOT the culprit, but it's not going back on because I sold it (to a S197forum member).

I'm leaving the engineered stock DS on till/if I get the vibe resolved and then maybe I'll buy another, or if I can't resolve it with the stock axle, and end up getting a complete Currie 9" axle, then I'll have to use their DS. Or maybe I'll try a "stock" Bullit rear axle...with the 3.73's instead of the 4.10's, in which case I could do the Spyder again.

FYI, the dealer mechanic said the crush collar & pinion flange should not be re-used when swapping pinion flange, so the Spyder install should entail replacing the seal and crush collar.

FYI, I had the tires re-balanced to the nearest 1/10th of an OZ this morning to eliminate them as a possible culprit, but I hear what you said, the tolerances need to be that much higher at the higher rotational speed. On the Other hand, they (Discount) used to be able to balance one of my previous car's 335/35/17's (i.e. much wider) tires to where I regularly went 140-150 (on a closed course, of course) without vibes. I mention that because they were much wider tires and as such were inherently harder to balance. We'll see. Keeping my fingers crossed.

 

[spyder7724]

I agree wholeheartedly that the Spyder was NOT the culprit, but it's not going back on because I sold it (to a S197forum member).

I'm leaving the engineered stock DS on till/if I get the vibe resolved and then maybe I'll buy another, or if I can't resolve it with the stock axle, and end up getting a complete Currie 9" axle, then I'll have to use their DS. Or maybe I'll try a "stock" Bullit rear axle...with the 3.73's instead of the 4.10's, in which case I could do the Spyder again.

FYI, the dealer mechanic said the crush collar & pinion flange should not be re-used when swapping pinion flange, so the Spyder install should entail replacing the seal and crush collar.

FYI, I had the tires re-balanced to the nearest 1/10th of an OZ this morning to eliminate them as a possible culprit, but I hear what you said, the tolerances need to be that much higher at the higher rotational speed. On the Other hand, they (Discount) used to be able to balance one of my previous car's 335/35/17's (i.e. much wider) tires to where I regularly went 140-150 (on a closed course, of course) without vibes. I mention that because they were much wider tires and as such were inherently harder to balance. We'll see. Keeping my fingers crossed.

I don't agree with his opinion about replacing the crush sleeve since Ford doesn't even suggest (in their manual) replacing it when changing a pinion seal. If the instructions are followed and the bearing preload is okay then there is no reason to dive into the differential unless you just want to charge the customer a butt load of money or you are just bored and need something to do.
In a perfect dealer world they would just replace everything including the rear cover and bolts or just R&R the whole rear assembly with brakes and all
as far as the seal goes that's up to the installer and the mileage on the vehicle. Now that some of these cars are almost 3 years old I will have to update the instructions with a recommendation that cars with over 30-40k probably should replace the seal while they are doing the install just to be on the safe side.
Hope you get things worked out soon

 

[scramblr]

Hmmm, it's a Mustang, it's going to squeak, creek, and vibrate. Bet ya the vibrations were there all along, but like you said, the suspension mods probably amplified it. Also, after changing out the OEM DS to the Spyder, you may have started paying more attention to the noises and vibrations. If a pefectly quiet, vibration fee car is anyone's goal, a Mustang ain't it.

 

[F00Mustang]

Fix
Or
Repair
Daily



I actually have the exact same problem. I couldn' tell you when mine started. I noticed it when I installed a DSS driveshaft. I went back to the stocker only to find it was still there, just dampened. I have the exact same setup you do. 4.10s and all.

I've had this problem for almost a year now and just can't seem to find it. If you figure it out, please let me know.

 

[Bubbamax]

Not bad...you have to have the windows up, radio off/muted, and be on a reasonably smooth road, but it's still there, albeit dampened by the noodle's rear section. I guess the poly bushings from the BRM rear sway bar and CHE UCA and panhard bar do transmit more NVH to the body than the stock bushings, because I really don't recall feeling the vibe prior to their installation.

Hello MrClean I have the same vibrations after installation of the BMR LCA, UCA and adjustable panhard bar. After playing with the panhard bar I found a setting that suited my tolerance but was unable to make them disappear totally so my guess is the poly bushing do transmit a lot more NVH...

But adjusting the panhard bar did the trick for me.
Good luck.

 

[MrClean]

Hmmm, it's a Mustang, it's going to squeak, creek, and vibrate. Bet ya the vibrations were there all along, but like you said, the suspension mods probably amplified it. Also, after changing out the OEM DS to the Spyder, you may have started paying more attention to the noises and vibrations. If a pefectly quiet, vibration fee car is anyone's goal, a Mustang ain't it.

Yup you're probably right about pating more attention after the Spyder went on, and the suspension mods amplifying the vibes.
My wife's comment: "you didn't buy a BMW...."

I actually have the exact same problem. I couldn' tell you when mine started. I noticed it when I installed a DSS driveshaft. I went back to the stocker only to find it was still there, just dampened. I have the exact same setup you do. 4.10s and all.

I've had this problem for almost a year now and just can't seem to find it. If you figure it out, please let me know.

I certainly will. The dealeship is installing a vibration analyzer, which has several sensors that they attach to different parts of the driveline and suspension, then the car is driven, and the sensors report back to a central box...and the sensor that reports back the largest vibration provides a clue as to where the vibe is originating from....so they'll install it, and call me to drive it, and then they can open the rear and measure runout on the carrier...and hopefuly they'll finmd it's "out of spec" and replace it...and hopefully that will be the problem...if it's not. then it get's harder to pinpoint...axles, brake rotors....etc, but I'll report back on this thread after the vibe analyzer test and diagnosis.

Hello MrClean I have the same vibrations after installation of the BMR LCA, UCA and adjustable panhard bar. After playing with the panhard bar I found a setting that suited my tolerance but was unable to make them disappear totally so my guess is the poly bushing do transmit a lot more NVH...

But adjusting the panhard bar did the trick for me.
Good luck.

Tha's interesting to hear...where is it set to? Do the tires stick out of the wheel fenders equally? It's interesting that the stock panhard bar is filled with a vibration-supressing sand....

I wonder if before taking it to the stealership I should replace the stock panhard bar and test?...

 

[Bubbamax]

Yes mine is set so the tires stick out equally...

Replacing the stock one is worth a try in my opinion and it doesn't take long.

 

[mwilkes]

consider getting your wheels checked. I have an 07 and an air pressure sensor was on a loose band and moving around on my wheels. Not sure what year yours is but it's worth a try.

 

[MrClean]

consider getting your wheels checked. I have an 07 and an air pressure sensor was on a loose band and moving around on my wheels. Not sure what year yours is but it's worth a try.

Yes, good suggestion. I had them balanced on Tuesday at Discount, and they all came out good, but I'm curious how you discovered the loose sensor...and where they discovered/fixed it for you.....tell us the story, please.

 

[mwilkes]

well, I was just getting vibrations and i couldn't explain them. I had the wheels balanced and it went away. The vibration came back in under 50 miles so i told them i wanted the wheels broken down and the sensors removed. When they broke the wheels down you could see the senosrs were not in the right place on the band (opposite the valve stem). Anyway, i had them remove them and I put them in a PVC tube that built. I have a valve stem on one end and i keep it pressurized at 40 psi. this keeps the computer from alerting about the wheels being low.

 

[MrClean]

Mitigated, not eliminated:

Fix
Or
Repair
Daily



I actually have the exact same problem. I couldn' tell you when mine started. I noticed it when I installed a DSS driveshaft. I went back to the stocker only to find it was still there, just dampened. I have the exact same setup you do. 4.10s and all.

I've had this problem for almost a year now and just can't seem to find it. If you figure it out, please let me know.

OK, here's what I did: instead of replacing the stock panhard bar, I replaced the stock UCA. My reasoning was that the UCA has much more bushing material, and that the stocker's rubber bushing is a lot softer and hence would absorb the hum/vibe.

It worked...I can still dedect the hum at 110+, if I'm on a polished concrete road, and only because I'm "tuned" to it and looking for it, but otherwise it's undetectable. I guess the design of the CHE UCA bushing: metal sleeve, surrounded by nylon bushing for rotation, surrounded by poly-bushing material is such that the actual bushing material (which would absorb the NVH) is that much thinner and harder than the stocker.

I'm sure I could further "polish" the situation by returning to the stock, sand-filled panhard bar (a damper by design in of itself), but I like the axle being centered, so I'm leaving the CHE installed.
(BTW, I checked out 5 mustangs on the dealer's lot yesterday: to SGT's, 2 Roush 427's and 1 GT500, and they all have the driver's side tire sticking out 3/8" further that the passenger's side; what's with the engineer that was charged with determining the length of the panhard bar? Was he smoking weed?)

So FOOMustang, maybe you should give this a try. The fact is the aftermarket UCA DOES transfer a lot more NVH to the car, even with poly bushings. The only thing that would be a concern in your situation is the pinion angle with the DSS DS....but then again, Spyder has lots of people running his DS with an otherwise stock setup.

And for the record, THE SPYDERSHAFT WAS NOT THE CAUSE OF THE VIBE, although it inherent properties (hollow aluminum cylinder) magnified it.

 

[ZmanM3]

Interesting, I'm glad an adjustable panhard bar is one of the mods going on.

 

[F00Mustang]

What you say makes sence, but the only suspension mods I had when I first noticed the vibration was the BMR non-adj LCA's, and then I added the DSS shaft. I've since changed everything else; springs, PH Rod, UCA, LCA relo-brackets, but nothing has made it any better or worse.

As for the factory shaft, i did put it back on before doing anything else to see if the DSS shaft was the culprit, even had the DSS shaft re-balanced. But, like you, once I was tuned into the vibration, I found it was still there with the OEM shaft, even though it was not as evident.

I think my next move will be to actually pull off the LCA's and inspect them for any damage or problems. I have the origional run of these from BMR, and I know they had a problem with the bushings on them getting blown out. That's why they went to a boxed design later.

I'm also going to take my car into a shop and have them se the pinion angle properly for me. Maybe I'm doing something wrong there.

Thanx for all your input. If you find anything else, let us know.

 

[MrClean]

It's listed in your sig...is it not installed yet? The simplest way to center the axle is to hang "plumbs" from each rear fender well, and measure from the thread to the center-most section of the brake rotor...and have a ½ tank of gas, and a buddy sitting in the driver's seat to simulate a standrad deviation of driving weight.