I have a 94 Exporer that I just found out almost losing control at 55MPH is acceptable according to Ford service bulletin 96-4-15. My Wilderness ATs were replaced with newer W ATs before I bought it. I've had it at Firestone shop twice for balancing, etc. with no solution to vibration on freeway problem. This time they printed the service bullettin decribing the problem perfectly. Ford said it wasn't their problem since it is out of warranty. Most rollovers occur at that speed and I suspect that is why the tires fly apart. My passenger seat shakes like it is coming off its mounts. Surely this has got to put stress on the tires. I need some advice from others who have solved this problem. In addition I have had to have my rotors resurfaced 3 times in the last 3 months because of warpage. Is this an end result of the shimmy? I'm leaning towards the Michelin LTX M/S as recall replacements and Edelbrock ISAs for shocks, comments? I'm in Las Vegas so no snow and not much mud, just hard sand and rutty clay that I drive over at bone jarring speeds. I want shocks and tires that will take up any damaging jolts and give good highway ride. Would appreciate recommendations from owners.
Copy response to direct email at dahexp@auction-net.net

 

What you are describing is not what is stated in the TSB, and nowhere does it state what is acceptable. The TSB is referring to a resonance, which causes vibration. What you are describing leads me to some questions:
1) You bought this vehicle used or new? Did the problem happen all of a sudden? If so, then I would start suspecting front end geometry. If you purchased this thing used, how was it treated by its previous owner? If the problem is so severe as you state, why is it being addressed now after 7 years?
2) Having your rotors resurfaced so many times begs the question of you driving habits (do you ride the brakes?), or the competency of the mechanic doing the service. What shape are your calipers in? If they are sticking from improper slide lubrication, they may build excessive heat, and cause warpage. Has the mechanic actually used a guage to measure runout?
3) Have you had your front suspension thouroughly checked, by a reputable service center that is familiar with the Ford TTB system?
I'm not try to pick a fight, but I want to suggest that you need to have your pivot bushings checked out for wear, and have your front brakes gone through thouroughly. Maybe get the calipers rebuilt, or replace them (~$50 for both). Lastly, get a good alignment performed. You will feel the difference when braking, and going down the road.

 

Let me respond to some of your questions.

"What you are describing is not what is stated in the TSB, and nowhere does it state what is acceptable. The TSB is referring to a resonance, which causes vibration."

Quote from Service Bulleting text:

Issue:
A vibration/shake may be felt in the seat and/or floor at speeds above 50mph and peaking near 65mph on some vehicles. This condition is not rpm dependent and occurs at all driving modes, i.e., acceleration, cruise, and deceleration. An "after shake" condition may also exist when driving over a bump at speeds less than 45mph. This condition may improve with tire balancing or tire exchange, but may not be copletely eliminated. This may be caused by the movement frequency of the engine aligning with the tire rotation frequency causing the vibration/shake."

What you are describing leads me to some questions:
1) You bought this vehicle used or new? Did the problem happen all of a sudden? If so, then I would start suspecting front end geometry. If you purchased this thing used, how was it treated by its previous owner? If the problem is so severe as you state, why is it being addressed now after 7 years?

I bought this used and it had a slight shimmy at the time which I assumed was balance since the ATs were replaced shortly before. I took it to a Firestone dealer on the off chance that there was tread seperation occuring. They balance and rotated the tires and stated that I had a bent rim that they relocated to the rear. The shimmy changed after that so I assumed the rim was the problem. I took it back to the dealer and had them check the bent rim. They said the rim wasn't bent enough to cause any problems so they rebalanced all the tires and the shimmy got drastically worse. I returned the vehicle to the dealer and they humored me and took the bent rim off and replaced it with the spare. The shimmy changed again, but didn't stop. I returned and they searched the Ford Service Bulletins and found the symptoms decribed perfectly. I went to Ford dealer where I was told it wasn't their responsibility. Why do I have to pay for a documented defect in yoiur vehicle?

2) Having your rotors resurfaced so many times begs the question of you driving habits (do you ride the brakes?), or the competency of the mechanic doing the service. What shape are your calipers in? If they are sticking from improper slide lubrication, they may build excessive heat, and cause warpage. Has the mechanic actually used a guage to measure runout?

I had a complete brake job done at Pep Boys 3 months ago. A month after it was done I got a shimmy when braking. They resurfaced the rotors again and all was well until yesterday when it started again. I do not ride the brakes or heavy brake. I haven't pulled a trailer since the last job done so I'm not overloading the brakes with a trailer.

3) Have you had your front suspension thouroughly checked, by a reputable service center that is familiar with the Ford TTB system?

Everytime I've had the tires or brakes looked at they have checked the front end. Whether they are familiar with the system I can't tell you.

I'm not try to pick a fight, but I want to suggest that you need to have your pivot bushings checked out for wear, and have your front brakes gone through thouroughly. Maybe get the calipers rebuilt, or replace them (~$50 for both). Lastly, get a good alignment performed. You will feel the difference when braking, and going down the road.

I guess I'll wait for the ATs to be replaced for the last time and then start all the rest. Hopefully the recent law suits will ferret out the truth and a total recall will be issued or at the very least a repair order be issued. Reading this list others have experienced the same problems. It's interesting that all the rollovers, blamed on the tires, occur at the speed range in question.

 

If you look at what you posted with the TSB, it states a vibration felt in the seat, no extreme buffeting, which is what you are experiencing. The affected parts are motor mounts and rear shocks, not front end suspension components.I have a Bronco that used to get passed in the snow by Mustangs because the front end was so erratic. It was axle pivot, and radius arm bushings that went bad. It really is worth it to have someone knowledgable in Ford TTB/IFS look at your front end.
The Firestone dealer started playing "ring around the Explorer" with a bent rim. Bad practice. If the bent rim was enough to change the vibration when they rotated the tires, why wouldn't it have been bad enough to replace after that. By your statement that they "humored" you, it sounds like they had no intention of fixing your problem, especially in the middle of a recall for their defective tires (look at the NTSB findings on the Decatur plant, where all the defective tires were from). Does your vehicle show any signs of off roading underneath from the previous owner? Look for scraped oil pan/gouges in suspension parts, dented/leaking shocks, old mud/clay caked in hard to reach places.
If someone in your area offers a free brake inspection, I would take it, and find out what Pep Boys did not do. You should not have had to have your rotors resurfaced so soon after the job. They cut corners on you. Pep Boys didn't go bankrupt without a good reason.
I'm just curious as to how big a trailer you tow with your Explorer. How does it do?
As for waiting for the truth to come out between Ford and Firestone, I doubt the whole, or real story will ever come out. Even if it does, don't you owe it to yourself to find out if you have another problem besides tires before it's too late?

 

I have a theory that warped rotors can be caused by loose wheel bearings. I had an 83 Ranger that didn't have front brakes replaced for 107K miles, never had the rotors turned. I bought and 88 4x4 Ranger and had to have rotors turned at 20K miles. After watching an off-road show on TV, I learned that slightly loose wheel bearings can cause more than normal brake pedal movement, especially on sharp turns, such as in parking lots, etc. After checking, I found that both my front wheel bearings were slightly loose. After correcting that, I never had to have the rotors turned again.

I have a 91 Explorer which had some of the vibration symptoms you mentioned when I bought it with 121K miles. It took several trips to the tire store before I finally got a good balance job, which eliminated the problem. I think tire balancers get out of calibration, and most people just accept the poor balance, or their suspensions accomodate it better. The Explorer is stiff enough that vibrations are more noticeable. Be tough! make then get it right, or go to another store.

I also have 98 XLT V8 AWD, and it is just as sensitive to tire imperfections as the 91, but nothing that can't be corrected with good service.

Winford