As mentioned in the
previous update lowering the tire pressure seemed to tighten up the
steering but the front end wobble soon reappeared. As per the
various death wobble check lists I picked up some cam bolts to give
the front end a bit more caster, as it sat I had approximately 5
degrees. Dialing the cam bolts to the max really tightened up
the steering feel but seemed to make the wobble worse. At this
point this whole problem was really getting aggravating so I decided
to position my bullet cam under the Jeep to film various positions
in the hopes of seeing exactly what was happening.
After a few days of
filming I was able to eliminate the steering gear as a culprit as
well as the ball joints. When the wobble occurred you could
clearly see the whole axle shudder back and forth. I pulled my
track bar one evening and closely inspected everything but didn't
find anything that had play in it. Next up was the control
I hit pay dirt on the
drivers side arm. One of the standard check items on the
various death wobble checklists is to make sure all the bolts are
tight on the control arms. In this case it looks like the
bolts may have been too tight since the ends of the ball in the
misalignment joint were crushed down. This could have been
caused by the wobble itself.
I will say that no
matter what caused the damage, the slot in the lower control arm
mounting bracket will cause this issue again as only a small portion
of the misalignment ball rests against the control arm (note the
indents). The reason for the slot is to allow the use of cam
bolts to adjust the caster on the front axle which ironically are
not supplied with the vehicle from the factory.
On the other end of
the control arm is another glaring design flaw. Here we have a
stepped bolt which in no way locates the arm to the mounting bracket
without a ton of slop.
When I pulled the
upper control arm I discovered the same thing as the lower control
arm, the bolt is way to small for the hole in the bracket.
Not one for half-ass
fixes I have determined I will need to replace the lower control arm
brackets with a pair that have a single hole in them as well as
properly sized bolts. Next a
set of adjustable lower control arms will replace the existing ones
so I can adjust the caster as needed. Since the cost of a pair of
adjustable lower control arms is only slightly less than the cost of
a new set of lower long arms I am going to take this opportunity to
upgrade the front end. The longer arms will eliminate the
steep angle on the front links and provide a much nicer ride.
I have sourced a set of Rubicon Express Long Arms (RE4000 &
RE4010) and some new control arms mounts from
Ballistic Fabrication (frame end) and Currie Enterprises (axle
end) for the conversion. I should be able
to re-use my existing upper arms with the new long arms and
eliminate the oversized mounting hole at the frame end.
Here's a comparison
shot showing the existing short arm and the new long arm.
To accommodate the
added length of the new control arms I need to remove the stock
mounting bracket and attach a new one back by the TeraFlex belly-up
skid plate. I am pretty sure I can tuck the bracket in
ahead of the first mounting bolt for the skid plate so the two are
independent. After mocking up the drivers side link I can see
I will need to lengthen the upper control arm slightly to get the
bracket mounted out by the frame rail. For reference it looks
like the angle on the lower control arms will go from just over 20
degrees to 5 degrees.
To lengthen the upper
control arms I am planning on sleeving them. This will
also allow me to build in more caster adjustment (if needed).
After discovering the
rod ends in the track bar I had made were already loose after just a
few months usage I decided to go back to the Rubicon Express track
bar. The RE track bar used a rubber bushing at one end which I tried
to eliminate to cut down on all play in the track bar but the two
piece rod ends wore out much faster than I expected. I also used a 3
piece rod end like the RE track bar had initially. With this
change I gain back some clearance between the track bar and front
diff cover, despite moving the straight track bar around and adding
longer bump stops I still managed to rub the front diff cover when
the drivers compressed fully.
The rig is also
sporting some new shoes, a new set of Mickey Thomson MTZ's.
These things are much quieter than the MTR's they replaced and so
far they seem to work as well if not better off-road. I don't
notice as much side to side tire slippage when climbing over