'97 AWD death wobble (front)

[Hacra]

So, i have had this issue for a while now and i have been slowly (as i get time) been eliminating issues one by one.

When driving at very low speeds and if i let go of wheel, every one rotation of wheel, the steering wheel will jump to right around... 5-10°? rather strongly. What i find odd is that even at 1mph the steering wheel really wants to turn to right by it self.

When driving past 50mph vibration gets rather intense, when driving below 50mph vibration can be felt, when driving exactly at 50mph vibration seems to be at most tolerable levels for some reason. Can't really drive faster because the vibration gets really bad at higher speeds.

Other symptoms:
When slowing down to lights and when car is just about to stop, every half rotation of tire i can feel ABS doing its work even though tires aren't slipping at all? no idea what might cause this.

What has been done to get rid of the issue:

Front left CV axle replacement
Front left wheel hub replacement
Front left upper control arm replacement
and i just changed tires from back to front to see if tires would cause the issues, they do not (unless front and back rims are bent? which i find unlikely)
Alignment has been done.
Made sure tire pressure is correct and equal in every wheel.

I have bought lower ball joints, drive shaft(s) u joints, but haven't got the time to replace them yet.

Could this issue be caused by worn front sway bar bushings, tie rod ends? does the dana 35 have some sort of support bar thing which might have worn bushings like in certain chevy products which causes the notorious death wobble.

Any help is appreciated, thank you.

 

[974X4BLACKSPORT]

The "ABS" should not be doing anything at any moving speed unless one wheel stops spinning (im sure your know this). If you suspect the "ABS" system, try pulling the fuse, then roll along at your slow speed and see if the steering wheel still turns to the side.

 

[shucker1]

@Hacra ,

From what you are describing in you first post that would seem like classic symptoms of a slipped belt in a tire.

Steel belts within the tire fail and bunch up to one side and create a "Lump" in the tread face.

Easiest think to do would be to get each wheel off the ground a feel around the face of the tread to see if you can feel the lump.

You mentioned the steering wheel oscillates at low speed with "No Hands". That's the lump hitting bottom.

Did it do that after you rotated the tires?

If so you may have (2) bad.

 

[Hacra]

The tires are OLD, so old actually that i am shamed to say the amount of years they are studded winter tires, i have been seriously thinking of buying new tires with rims.

It is entirely possible the tires (and rims) are well past their life expectancy, after all the car is good 22 years old, will keep you guys posted as i go through the process (once again).

 

[shucker1]

I would focus on the tires first.

It's pretty hard to bend a rim without blowing out a tire.

 

[Mbrooks420]

I’d get new tires before they fail.

The sway bar won’t have any steering effect like you’ve described.

 

[MAS Tequila]

It also sounds like you have a warped rotor or two.

 

[fast_dave]

Hacra -

With regards to steering wheel movement & vibrations, as others have suggested, tires sound like your problem.

With regards to ABS abnormally activating, you could try cleaning the ABS Sensors as it costs nothing but your time, and eliminates one possible cause. Regardless, more than likely no one has ever cleaned off the ABS Sensors, and they're probably coated in grime which will affect your ABS performance.

• Remove front wheels, remove one bolt holding in ABS Sensor, and CAREFULLY twist & pull to remove the ABS Sensor and clean it off. The ABS Sensor body is plastic and fragile since it's 20+ years old.

• Remove ABS Sensor from top of rear differential and clean it. NOTE: on a '98 it's a LARGE single sensor located on top/passenger side of the differential, one bolt holding it down. The rear ABS Sensor is a very sturdy assembly, and it is removed by twisting it right/left as pulling it upwards. It might be in a different on a '97, meaning that perhaps each rear wheel has a sensor like the front wheels. Hopefully someone with a '97 will read this and chime in.

Hope that helps and Happy New Year!

 

[gmanpaint]

Rear 2nd gen Explorer ABS Sensors are all the same from 95-01. They started pulling double duty in 97.5, after the mechanical VSS was dropped from production.

OP: Running old worn winter tires year round? Really? Just get a new set of tires.

I would be replacing the rotors/pads, and probably the calipers as well.

Check all 4 ball joints, and both tie rods- inner's & outer's for any play/slop, replace as found.

 

[shucker1]

It also sounds like you have a warped rotor or two.

Warped Rotor would make the brake pedal pulsate.

It would have to be darn near broken to pull on the steering wheel.

 

[shucker1]

It might be in a different on a '97, meaning that perhaps each rear wheel has a sensor like the front wheels. Hopefully someone with a '97 will read this and chime in.

Everything was solid rear axle until 2002?

Don't see logic behind 2 rear sensors on a solid rear axle.

Almost all of them I have ever seen have the tone ring attached to the center ring gear carrier.

Perhaps I'm wrong.

 

[Mbrooks420]

Pretty positive all second gens have a single ABS sensor in the rear diff.

 

[Hacra]

Okay... The ABS sensor should be fine as i just replaced the whole hub with the new sensor.

Earlier this year i changed pads to front, it is possible the rotors are warped, but as i look at the rotor from close it does not seem warped and yes i know you can't measure it just by looking.

rear brakes are completely new.

@gmanpaint I do not run old winter tires year round, just during winters (as it is required by law here -> not allowed to use summer tires in winter), the winter tires have maybe.. 3-5 months of usage per year, depending on the winter.

What bothers me most is that the vibration stayed even after swapping the tires from front to back, new set of tires would be around 300€ around here (all 4).

Edit: i fear the problem will persist if i just change the tires, not too sure about the rims as they had quite heavy balances in them already. That's why i made post earlier about new rims

Alignment data i got recently:

Front left toe before -1.00° after 0.07°
Front right toe before 0.09°after 0.09°
Caster left: 3.56°
Caster right: 4.58°
KPI left before: -1.23° after: -1.19°
KPI right before: -1.00° after: -1.04°

 

[Mbrooks420]

Have you ever been towed, or turned the wheels with the motor off? It’s possible you have a few different issues, one of them being air in the rack. Start the motor, and let it warm up. After the idle drops, turn the wheel lock to lock several times. This should push out any air. Worth a try, since it’s free.

If you feel the ABS activating, it thinks a wheel is traveling a different speed. If you used cheap hubs, they come with cheap sensors. I had to replace a hub, and had an ABS issue right after. A new sensor corrected it.

 

[CDW6212R]

There could be more than one issue going on. I'd worry most about tires and the AWD transfer case, which is destroyed by tires that aren't equal in diameter. If the tires are not the same, you have to buy four new tires, no options.

If you think the tires are all identical still, then remove the front wheels and carefully check the hub bearings. It sounds like a bad bearing somewhere, I'd bet on a bad hub(which would also include the ABS issue). Did that problem happen with the Summer tires, if not sure put them back on for a test?

If it still seems all good, remove the front driveshaft, to isolate the problem. You can do this like the Summer tires for testing. You need to find the problem first if possible, then fix it. If nothing turns up with the basic checks and tests, then you start replacing the parts which are the oldest or unknowns, or most prone to failures.

How old is the front diff/grease? If it has any kind of leak at the axle seals, then it could be nearly empty, which will kill the diff. It's easy to add grease to the front, remove the left wheel, and the left side fill plug of the diff. Add synthetic 75W-90 or better until it drips out.

 

[Hacra]

Thank you for all the replies and advice, as soon as i can get the chance to do all the things mentioned above i will give them a try and slowly start to eliminate the possible causes.

Since i will need new winter tires anyway, i will go and order them now if they wobble i'll just swap them to summer tire rims and see what happens then.

And what goes to diff fluids; i have no idea how old they are, possibly very old, is the dana sealed with RTV or gasket? already have gasket for the ford 8.8, but not sure, might as well change fluids to both since i am at it, how many quarts goes to front? rear was around 3?

 

[fast_dave]

Okay... The ABS sensor should be fine as i just replaced the whole hub with the new sensor.

OK - You are writing that 1 ABS Sensor is new - have you removed and cleaned the other 2 ABS Sensors so you can begin eliminating the problem by starting with the most basic "fix"? Currently, you have 1 ABS Sensor that is New & Clean, and 2 that are Old & Dirty. Hope that helps & Happy New Year!

 

[Hacra]

I have new hub to right side, but haven't got the time yet to replace it yet, will be doing it soon though. I replaced the left side as that is where the vibration can be felt as far as i know.

Edit: rear ABS sensor i do not have, but will have to look how to replace it. will buy it soon.

Also, i just ordered new tires, 5-7 work days and they're here.

 

[CDW6212R]

Don't worry about the front ABS sensors in a 4WD hub. In these it's inside the sealed hub. They basically never go bad, unless the hub is a cheap brand and who knows if they will last.

The sound or feeling that you think it's from the left front, don't rely on that solely. It's common for the source to be near but elsewhere. I've had my front driveshaft CV joint go bad, and thought the source was the left front bearings or axle CV. That's why I mentioned to later on remove the front driveshaft, that will isolate the problem to be forward, or in the transfer case/driveshaft.

Go slow, there's a lot that can be a problem, and it takes time to sort it out.

 

[fast_dave]

Hi Hacra,

All I am saying is that you should try is removing the 2 old ABS Sensors, clean them off and put them back on. At this stage/point, I am not saying you should go out and buy new sensors. With regards to your old ABS sensors - the "faces" of these sensors get contaminated with a coating of fine ground metal dust. The metal dust contamination will cause the ABS system to not work correctly. That's why it's worth a try to remove and clean them, as more than likely they have never been cleaned.

REAR ABS SENSOR: The rear ABS sensor is 1 BIG sensor located on top/passenger side of the rear differential. 1 bolt holds it down. After you remove the 1 bolt, you remove the ABS Sensor by twisting it right/left while at the same time pulling it upwards.