Death Wobble - new restoration...

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Joined
Jun 4, 2004
Threads
74
Messages
234
Location
Denison, Texas
I've read virtually all of the "death wobble" posts on this board and have come to the conclusion that there is "no single cause" for the carnival ride...there are many reasons why this happens and thought I would log my findings.
There are several potential problems with the geometry of my rig....Here's the history and condition of my truck:
Purchased about 8 months ago - Body in pretty good shape but in need of a drivetrain.

PO installed front disc-brake axle from an 82 FJ40 with 3.70 ratio
PO intalled rear axle assembly from FJ60 3.70 ratio
PO Installed (BRAND NEW) Never USED - ALCAN springs

----My work---
I disassembled the truck - stripped-primed and painted OLIVE Green
Installed 5.3L Vortec LS1 with SM465 and Toyota 3-Speed TCASE (no problems)
Converted to Power Steering (works great)
Installed 4 new Rancho Shocks
New Wiring Harness from Painless
4 New OEM Toyota Rims and BF Goodrich 34x9.50
Installed 1" wheel spacers on front rims to account for FJ60 rear axle width.
TEXICAN rebuilt both front hubs - birfields, bearings, etc... shimmed the front axle and aligned it.
---Fast forward to the problem---
The truck runs and drives great until I reach approx 30-40 MPH, If I let off of the accel pedal, the wobble starts and is pretty bad unless I slow down to stabilize...I can accelerate back up to 30-40-50 and all is ok for a while until I hit a small bump or slow down....then the wobble comes back.
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Problems that could contribute to the wobble:
The (FRONT) Driver's side frame rail appears to be about 2 inches LOWER than passenger side, but there is NO EVIDENCE of any frame damage - I can't see why it's lower on front drivers side. Also....The front shackles are at a different angle which makes me think that either the front springs are reversed or the springs are bad. I don't know whether to shim one of the springs, or just replace them - is this common ? Also... The front U-Bolt Plates are not positioned the same - They are installed opposite from each other, but I don't think this could cause 1-2" difference.

When measuring the distance between the rear tire and inner fender well - The Rear Axle appears to be setting about 2-3" more to the Passenger side.

The Tie Rod ends appear to be pretty fresh and doesn't have any play or appear to be loose.

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Any ideas ?
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I'll eliminate the causes one by one and update this thread with the results.

:hillbilly:
fj40.webp
 
Last edited:
Good Luck.I sure would fix all the suspension differences. Mike
 
Your frame rail and differnt angles on the shackle sound like typical cruiser lean. Do a search on it. What's your caster at? I have read that too much caster can cause wobble. Other factors are wheel/tire balance and loose wheel bearings.

Sounds like your rear axle didn't get centered corretly. You said it came from an FJ60? If so either the spring hangers or the spring perches had to be modified. Maybe the PO didn't get them in the right spot. I'd get that fixed, but I'm skeptical that it's the cause of your wobble.
 

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