Re: The infamous Death Wobble Hi Guys, This was originally posted by UBS or Suresh Stephan on jeepthrills
Problem:
Wobbling of the front wheels.
This is quite common in Jeeps - because the suspension and steering linkages are very long and a little fault gets magnified in to a big wobble - the mechanics call it "BUBBLE".
In most of the ladder construction chassis, the vehicle weight is reached to the spindle via, springs, hangers, kingpin, and so on. The weight falls on the spindle from behind, and not even from above. Imagine if the tilt of the spring seats is disturbed due to wear n tear, then it delivers the weight at a different castor angle, which is factory set. The stability of the front axle is sensitive, and any jerk or bump can cause an imbalance.
There are a number of contributing factors - single or in any combination. It is recommended that when attending to one, all should be looked at. Because, here, the labour generally works out to more than the parts and the hassle of getting stuck in the middle of nowhere. Brought on by:
High speeds.
Hitting a bump on the road.
Sudden manoeuvres of the steering wheel.
Immediate action to be taken:
Slow down.
Turn the steering wheel from one extreme of the free play to the other alternately - but don’t go swerving all over the road.
How to avoid the problem (without repairs):
Drive below the wobbling speed.
While driving keep moving the steering wheel from side to side - that is from one extreme of the free play to the other - the vehicle should not swerve.
If you have freewheeling hubs engage them.
In very extreme cases using 4 X 4 loads the front wheels and stops the wobble. But this is a last ditch resort as driving on hard surface in 4 x4 is a big No No.
Wobbling is a symptom of a greater malaise - it is not the problem. By fitting this you will never know of the real problem till it is too late.
However, A steering stabilizer can be added if one needs to enhance the
damping characteristics of the steering system. Useful for off-roading
where bumps that would normally cause an erratic motion of the
steering wheel would be dampened a great deal, leaving the driver in
better control i.e. reduces the effect of bump steer. It enhances the self-correcting tendency every steering system has i.e. especially useful when coming out of corners - usually attributed to the caster angle! Sometimes, it becomes necessary when using fatter tyres than normal. Therefore, unless one makes a conscious decision to use a stabilizer, it would mask genuine problems with the vehicle. Troubleshooting:
Wheel nuts: check for looseness.
Visual inspection of suspension for any signs of loose bolts etc.
- U clamp bolts on road springs.
- Shackles and hangers.
- Brake plates.
Wheel alignment - jeeps wobble due to miss alignment only when the alignment is way out and is really visible to the naked eye. However alignment should be checked to avoid uneven wear on the tires - off reading really knocks the alignment out. Wheel balance - not a problem really. Unless the rims are very badly damaged. Balance causes wobble at high speeds that we generally don't hit - 90 kemp or there about.
Hold the steering wheel firmly and shake - side to side - if there is any play - bushes have to be changed in the steering column.
Hold the steering wheel firmly and shake - up and down - if there is any play - the steering gear box has to be attended to. Reducing the play with the adjustment bolt on the box helps.
When was the last time that the whole suspension system was greased (like during water service)? A good greasing fills up the joints and eliminates minor wobbles too. Check shockers - mounting etc - one good one and one bad one causes this problem too. Always change both at the same time.
Now, support the chassis at the front end with 2 stands so that the front wheels are off the ground and the suspension system is free, there should be no jacks anywhere else. Now:
Hold a wheel from the top and bottom and shake - if there is play - problem in the king posts - bearings or shims - open and check - replace bearings or tighten shims by removing a few.
Definitely repack the grease.
Repeat for the other wheel.
Hold a wheel from the two sides and shake - if there is play - problem in the axle nut, wheel bearings or knuckle kit - open and check - tighten axle nut, replace bearings or replace knuckle kit. Definitely repack the grease.
Repeat for the other wheel.
Stand in front of the jeep. Look at the bell crank - it is an 8" long metal cylinder on the driver side chassis frame below the radiator. The top arm (drag link) goes to the steering gear box.
The bottom arm to the tie rods. The drag link can be seen by opening the bonnet. Ask somebody to turn the steering wheel from side to side. Both the arms should move smoothly. There should be no jerks or play - at the bell crank end. If there is, the bushes in the bell crank have to be changed.
Drag link: Both ends of the drag link have adjustable screws to reduce the play. Grease and tighten.
Steering gear box: Grease and adjust play. Check bushes for wear.
Tie rods: Looseness and play.
Take a long rod and put it between the chassis and leaf springs vertically and lever the 2 - any play in the bushes and shackles and hangers is clearly visible. Attend to as required. |