Death wobble continues..

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Phils67
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Death wobble continues..

Postby Phils67 » Tue Jun 12, 2018 5:14 am

I am still battling death wobble on this thing. My question is will a late model sway bar fit an early model frame? Thinking if it will i will try it and see if it helps. Are the front dimensions of the frame the same on all truck years? I know the early rear portion is wider. Not sure about the front though.
1967 J2000/ 4.0MPI/T18/D20/35s

RamJetFSJ
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Re: Death wobble continues..

Postby RamJetFSJ » Tue Jun 12, 2018 8:36 am

I dont think a sway bar will make any difference at all. Focus on ball joints, spring and shackle bushings, wheel bearings, tire balance and all the tie rods.
80 Wag in 73 attire, Ram Jet 350 power

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Phils67
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Re: Death wobble continues..

Postby Phils67 » Tue Jun 12, 2018 8:54 am

All new. No ball joints, its closed knuck. Everything is how it should be. Only happens on hard bumps or if i hit a mild bump while turning
1967 J2000/ 4.0MPI/T18/D20/35s

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Stuka
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Re: Death wobble continues..

Postby Stuka » Tue Jun 12, 2018 9:00 am

What are your alignment numbers? Toe in and caster?

A sway bar won't do anything for it.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
2017 JKU Rubicon Lifted and stuff
Pevious Jeeps: 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

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Phils67
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Re: Death wobble continues..

Postby Phils67 » Tue Jun 12, 2018 9:15 am

No clue. Did the alignment 2 years ago and havent driven it 2000 miles since
1967 J2000/ 4.0MPI/T18/D20/35s

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Phils67
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Re: Death wobble continues..

Postby Phils67 » Tue Jun 12, 2018 9:18 am

A passerby stopped one day when it happened. I had to hit the brakes and pull off to get it to stop. He said he saw my left front wheel going all over the place when it happened. Part of mw thinks the tiny stock tie rod causes it but i cant confirm
1967 J2000/ 4.0MPI/T18/D20/35s

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tgreese
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Re: Death wobble continues..

Postby tgreese » Tue Jun 12, 2018 10:22 am

Did you replace the kingpin bearings? Set the bearing pre-load?

Lifted? Is it spring-over or original?

If you do a lift, you have to check the alignment. A lift will screw up your caster, in particular. Apparently you can rent a gauge that will tell you the alignment at Autozone. Just heard about this on the KL forum - don't know much about it. Normally I would take it to a tire shop and ask them for the printout from the machine.

A shop can't do much for the price of checking the alignment. They can set the toe-in and center the steering. Anything else requires dis-assembly and parts.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 FCA Jeep Cherokee KL Trailhawk, ECO Green

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Phils67
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Re: Death wobble continues..

Postby Phils67 » Tue Jun 12, 2018 10:55 am

I rebuilt the entire front end from lugnut to ring gear and every part in between. The kingpins and bearings were brand new and preload was set to 13.5Lbs, spec iirc is 12-16Lbs. The alignment was done about 2 years ago, the lift is roughly 6 years old. Its lifted 4", original spring over axle front and still is. Shocks new, dual steering stabilizers new, kingpins new, kingpin bearings new, hub bearings new, tie rod ends new, drop pitman arm new, etc. It has had this issue since i lifted it. Every set of tires has been balanced on 2 separate machines to check accuracy and it all checks out fine. Its beyond frustrating. Only thing i think it could be are the puny stock tie rods and/or lack of sway bar
1967 J2000/ 4.0MPI/T18/D20/35s

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tgreese
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Re: Death wobble continues..

Postby tgreese » Tue Jun 12, 2018 11:45 am

Phils67 wrote:... It has had this issue since i lifted it. ...


Check the alignment. If you went to a shop and you did not get the printout from the machine, you don't know what the alignment is. Tracking is affected both by toe-in and caster. A lift will screw up your caster.

This is a '64 that still has Ross steering? Details in your sig would help. Is it like the CJ Ross steering with a bellcrank in the middle and a tie rod to each knuckle, or a single tie rod between the knuckles? With a lift, the angle of two Ross steering tie rods could be severe, and could cause a bump steer resonance.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 FCA Jeep Cherokee KL Trailhawk, ECO Green

SJTD
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Re: Death wobble continues..

Postby SJTD » Tue Jun 12, 2018 12:15 pm

Extended shackles or stock length? Long front shackles kill your caster.

Angle shims installed to help the driveshaft angle? These will give you less caster and can cause what you're experiencing.

Maybe worth trying some angle shims, thin side forward if springs are on top, to add some caster.

If you have the bell crank Tim's talking about how are its bearings?
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

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Phils67
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Re: Death wobble continues..

Postby Phils67 » Tue Jun 12, 2018 12:33 pm

tgreese wrote:
Phils67 wrote:... It has had this issue since i lifted it. ...


Check the alignment. If you went to a shop and you did not get the printout from the machine, you don't know what the alignment is. Tracking is affected both by toe-in and caster. A lift will screw up your caster.

This is a '64 that still has Ross steering? Details in your sig would help. Is it like the CJ Ross steering with a bellcrank in the middle and a tie rod to each knuckle, or a single tie rod between the knuckles? With a lift, the angle of two Ross steering tie rods could be severe, and could cause a bump

Front diff sits at the same level it was at stock height. Its a 67 J2000, it has crossover steering
1967 J2000/ 4.0MPI/T18/D20/35s

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Phils67
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Re: Death wobble continues..

Postby Phils67 » Tue Jun 12, 2018 12:34 pm

SJTD wrote:Extended shackles or stock length? Long front shackles kill your caster.

Angle shims installed to help the driveshaft angle? These will give you less caster and can cause what you're experiencing.

Maybe worth trying some angle shims, thin side forward if springs are on top, to add some caster.

If you have the bell crank Tim's talking about how are its bearings?


Original front shackles with new(ish) bushings
1967 J2000/ 4.0MPI/T18/D20/35s

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Stuka
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Re: Death wobble continues..

Postby Stuka » Tue Jun 12, 2018 2:38 pm

What you describe that the passerby saw thats a steering oscillation that is most typically caused by bad caster angle. You typically want about -4 to -5 degrees of caster (But this depends on tire side). The closer you get to zero, the worse your steering will be. You can check the caster angle yourself if you are parked on 100% flat ground, and put an angle finder on top of the knuckle.

Bad toe-in can also cause this, but not nearly as severe.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
2017 JKU Rubicon Lifted and stuff
Pevious Jeeps: 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

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Phils67
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Re: Death wobble continues..

Postby Phils67 » Tue Jun 12, 2018 3:38 pm

Stuka wrote:What you describe that the passerby saw thats a steering oscillation that is most typically caused by bad caster angle. You typically want about -4 to -5 degrees of caster (But this depends on tire side). The closer you get to zero, the worse your steering will be. You can check the caster angle yourself if you are parked on 100% flat ground, and put an angle finder on top of the knuckle.

Bad toe-in can also cause this, but not nearly as severe.

Tire size is currently 35x12.5R15. Using used federal couragia mt's which i wouldnt gift upon my worst enemy.. I will have to bring my angle gauge home from work tomorrow and check it. Whatever the cause is has me driving like a grandma anymore. The other day i had to lock the brakes up on main street and i spun 180 into the other lane. Without seatbelts either. Luckily it was early and there isnt much traffic in my podunkwhitetrashmountaintown that early or it could have been bad. I have been considering going back to stock height and this is one of the main reasons persuading me in that direction. Id be more open to keeping the lift if i could cure this issue. I will have to check the angle. I didnt think it could change since the axle bolts flat to the bottom of the spring. Higher curve to the spring or not, the mounting point of the diff remains the same, right?
1967 J2000/ 4.0MPI/T18/D20/35s

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Stuka
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Re: Death wobble continues..

Postby Stuka » Tue Jun 12, 2018 4:51 pm

The springs can be arched in a way to maybe point the pinion up, which decreases caster, and causes the exact issue you are seeing.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
2017 JKU Rubicon Lifted and stuff
Pevious Jeeps: 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

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Phils67
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Re: Death wobble continues..

Postby Phils67 » Tue Jun 12, 2018 4:57 pm

Ill check it tomorrow when i bring my gauge home. If the alignment shop missed this im gonna be so mad. Ive dealt with this WAY too long. Its put me literally in harms way on more than one occasion. My kids and puppy ride in this thing. I have never considered checking it since it should have been handled by the alignment shop but i will now. If thats the cause i will correct it myself. Obviously cant let boys do a mans job
1967 J2000/ 4.0MPI/T18/D20/35s

RamJetFSJ
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Re: Death wobble continues..

Postby RamJetFSJ » Tue Jun 12, 2018 5:29 pm

They make steel shims that bolt to the bottom of the spring pack using a new center bolt to adjust caster.
80 Wag in 73 attire, Ram Jet 350 power

SJTD
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Re: Death wobble continues..

Postby SJTD » Tue Jun 12, 2018 8:33 pm

You mentioned all the new stuff on the axle. What about the box? Has it been adjusted properly?
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

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Stuka
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Re: Death wobble continues..

Postby Stuka » Tue Jun 12, 2018 9:03 pm

SJTD wrote:You mentioned all the new stuff on the axle. What about the box? Has it been adjusted properly?


The box can cause steering wheel play, but it won't cause what he is having. The truck should be able to roll down the road with NO steering box and track straight and true.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
2017 JKU Rubicon Lifted and stuff
Pevious Jeeps: 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

SJTD
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Location: Lompoc, Sunland or somewhere between

Re: Death wobble continues..

Postby SJTD » Tue Jun 12, 2018 9:39 pm

True and I suspect caster is less than it should be as my posts above indicate but wandering is one thing. "Death wobble" makes me think something's loose.
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.


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