my brother test drove the jeep after i put the crankshaft sensor in, (thanks everybody for the info) he said at about 35 he tapped the brakes and the front started jerking really bad , he almost hit the bank, does anybody have any info on this , because I dont have a clue on where to start. it has 33 1250 thornbirds on it that are worn out, and has a 6" suspension lift.

 

how are the brakes on it...did you upgrade your brakes when you added the lift? and how well are they are they wrapped too? these could cause that problem ya may have?

 

x2 that.. are the rotors warped?

Death Wobble

http://www.naxja.org/forum/showthread.php?t=89888

http://www.jeepin.com/features/trackbarfix/index.asp
CHECK THIS JEEPIN LINK…. I AM DOINT THIS FIRST>>




Curing death wobble is definetly a reality. Death wobble isn’t similar to a wobble from an unbalanced tire. It is by far worse. When death wobble hits you will know… it’s a violent shake form the front end that feels like the Jeep is about to fall apart. Usually when it happens the only thing you can do to stop it is slow down. The first steps to eliminate death wobble should be a visual inspection of each component, check the bushings, tire balance and an alignment. There are some common things you must check anytime you lift your Jeep. Death wobble is experienced mostly on lifter Jeeps, however it is not uncommon for someone without a lift to experience the dreaded DW. Listed below are a few things you can check.

Torque specs:

Item ........................................ Ft. lbs. ................... Nm

Lug nuts (1/2 X 20 w/ 60* cone) .... 85-115 .............. 115-150
All tie rod ends ............................ 55 ..................... 74
Steering (both ends) .................... 55 ..................... 74
Shock absorber upper nut .............. 16 ..................... 22
Shock absorber lower nuts ............. 17 ..................... 23
UCA frame end ............................. 66 ..................... 89
UCA axle end ............................... 55 ...................... 74
LCA frame end ............................. 85 ...................... 115
LCA axle end ............................... 85 ...................... 115
Track bar frame end ..................... 60 ...................... 81
Track bar axle end ....................... 40 ....................... 54
Track bar bracket bolts ................. 92 ....................... 125
Track bar bracket nut ................... 74 ....................... 100
Track bar bracket support bolts ...... 31 ....................... 42
Hub bolts (3) ............................... 75 ....................... 102
Hub- axle bolt .............................. 175 ..................... 237

Alingment specs (stock):

Angle ............. Preferred ........... Range ............. Max R/L diff.

Caster ............ +7.0* ........ +5.25* to +8.5* ......... 1.25*
Camber ........... -0.25* ....... -0.75* to +0.5 ........... 1.0*
Total Toe-in .... +0.25* ....... 0* to +0.45* ............. .05*
Thrust angle .... 0* to ± 0.15*



Check your Track Bar, play in this can cause the axle to shake.
1. Bushings - check to see that they are not worn. Looks for cracks, and excessive play)
2. Angles - this angle should be the same as your draglink. Use an angle finders you can get at sears to determine this, don’t just eye-ball it.
3. Bolts – Make sure all bolts are tightened down to spec (some lift components have a different torque spec then)

Check the Axle, your mounts may be worn
1. Check the axle mount. Here is a good write up on a wallowed out bolt hole
http://www.jeepin.com/features/trackbarfix/index.asp
2. Check your Universal joints, a binding or lose U-Joint can cause DW
3. On the frame end if you still use the conventional Tie Rod End or (TRE) make sure that there is no play in this, as play can cause DW.
4. Look/Check for worn/torn boots on ball joints/tie-rod ends.

Check your Tires
1. Out of balance tires can cause shaking in the front end, which can lead to death wobble.
2. Make sure all of your lug nuts are tight, (Sounds elementary but it happens to the best of us)

Check your Frame
1. Small cracks in the frame can cause the steering box to feel loose, Shaking from DW can only make this worse. 33’s and larger should have some form of Steering box brace, or frame brace in.
2. If you have upgraded your frame mount, make sure its cranked down nice and tight. (best to use an impact gun)
3. A busted Frame Mount can cause play in the front end causing DW (Keep a watchful eye on the welds as welds in sheer can break over time.

Make sure you have a good alignment
1. After you get an alignment done, have them print out the numbers for you. An XJ should have a 7* positive caster angle. A lifted XJ can’t always have that high of a number because the pinion would become out of alignment with the front driveshaft. Pinion angle takes precedence over caster.
2. Make you sure you go to a place that will adjust the caster if necessary (either by shims in the frame side of the LCAs, or adjustable LCAs).

The more adjustable parts the easier it is to tune in your suspension.
1. Adjustable Track Bar
2. Adjustable Upper and Lower Control Arms (upper ones above 4” of lift). Not only are they adjustable, but they are stronger.


Things to remember:
1. A Steering Stabilizer (SS) is not a quick fix for DW.

Entire list of everything that can cause death wobble:
-Front tires out of balance
-Front alignment out of spec
-Loose track bar
-Worn track bar bushings
-Worn track bar end
-Need adjustable track bar
-Bad bushings/joints in control arms
-Worn/damaged steering stabilizer
-Worn/damaged shocks
-Worn/damaged tie rod end
-Bad U Joint
-Bad ball joint
-Loose frame mount
-Steering box looseness
-Need drop pitman arm
-Driveshaft(s) not balanced
-Bad front hub assembly

 

I have read many posts on numerous websites for this problem. I have tried everything - nothing ever fixed the problem -ever. I would get this violent Death Wabble at exactly 58-62 MPH, I have a 1998 Jeep Cherokee. Here is how, after 3 years of trying all suggestions, I solved my problem - completely my Jeep has Floating Calipers. Carefully examine the mounting pins for rust, if you can't EASILY slide them out, that is a problem. You should be able to push them back and forth very easily. I had to pound the pins out with a hammer. Press out the rubber boot on all of them, then take a file and scrape off the rust that built up inside the hole, some holes I had to chisel out the build up of rust - which causes the hole opening to be too small. After that, use high-temp silicone grease inside the hole, slip the boot back into the hole, grease the pins very well, slide them back into the boot - they will then move completely free. That solved my problem, absolutely, definitely, even with deteriorating rubber bushings everywhere and out of balance tires, on a Jeep with 179,000!

 

It doesnt sound like death wobble, it sounds like your rotors are warped. Death wobble when it happens is way different, you hit a bump and your rig goes left right and you can barely hold the wheel.

 

yea sounds like warped rotors new ones around here run about 25-35 dollars. not to bad

 

Although I had one warped rotor, the death wobble when it happened, occurred when I hit any bump, like the point where you travel across the seam when approaching a bridge. Also, on a smooth road surface around 58-62 MPH. My vehicle did go left right and I could not hold the steering wheel.