Hey Behemoth60. Looks like you have a awesome project ahead of you. I have a little bit of info I can pass along. I three linked the front of the lj78 this year. I ended up with around an 80% difference between between the upper and lower links and the separation is around 10 inches for the 35 inch tires I have. I found that with a 70% ratio the pinion angle changed to much from fully compressed to fully drooped and 80% lessened this change. .
Attention to Pinion angle is a lesson I learned the hard way. My second multi-link suspension was on TippyR, and under compression, the pinion would twist upwards to the point of binding the u-joint under extreme compression. This happened on the Rubicon climbing a ledge, just above Buck Lake. Broke the rear u-joint. (There's no way the Unimog pinion was going to break!) That led to a cascading series of other failures and I don't want to talk about Rubithon 2005 anymore, thank-you very much! But... pinion angle less on learned!
I have the 3 and 4 link calculators, and in addition to the above guidlines, will be seeking the following deisng numbers:
Rear end 2-4% squat.
Front end 0-1% squat
Rear Roll axis with 1-2% understeer.
Front roll axis flat.
Front and rear Roll axis at the same height and as close as possible to Center of Gravity
Suspension frequency of 1.10 front, 1.27 Rear (That's optimized for an 80kmph speed)
Spring Compression at rest: 55-60%
The most challenging part for me was the panhard and the steering. I found the down fall to the rhd is the power steering box is on the right side of the frame also the panhard mounts to the frame on this side too.
I have been looking at this. The big tires already tag the stock power steering box and are polishing it up. I am hoping the 80 series width axles will keep the tires off the steering box, or at least push them out enough to allow clearance to steer around.
The other option that might work is to use a LHD 70 sereis steering box... it is a mirror image of the RHD box, and sits would sit on the inside of the frame rail. I make have to shimmy the radiator over a CM or two to make it fit, and the PS cooling lines would have to move, but It should otherwise work.
The best option would be full Hydro. I want this truck to pass the local Provincial Authorities safety inspection, and there's some local discussion as to whether full hydro is 'legal' or not. The actual legislation does not specify ANY requirements for steering. Vehicle Inspection program's inspection guide tells the technician what to inspect for various types of steering, but leaves some vagary about what is acceptable steering. Here's what the Inspection Guide says:
Item Reject If
8.4 Pitman Arm. Worn Beyond Serviceable Limits.
8.5 Idler Arm. Worn Beyond Serviceable Limits
8.6 Steering Damper Worn Beyond Serviceable Limits
Leaking
8.7 Steering Shaft Any component of the steering shaft Worn Beyond Serviceable Limits
8.8 Steering Gear Gear is not mounted securely
Worn Beyond Serviceable Limits
Fluid Leaks
8.9 Rack and Pinion Mounts are loose, missing, or Broken
Dust Boots are torn or missing
Fluid Leaks (External)
8.10 Power Steering Pump Leaks
Hoses Leak
System is disabled
Active steering does not function as designed or diagnostic trouble code exists.
I will have to speak to some experts to figure out what the reality of an 'Alberta Approved' hydraulic steering set-up.