flat tow help (1 Viewer)

[gordon5211]

where is the tech section to post a question?

I am trying to flat tow this vehicle behind my motorhome.
I have a 97 land cruiser 80 series, right hand drive that I just imported from Japan. I have done a 4" lift with Dobinsons springs and shocks, 37" tires on 17" rims, and all the other necessary adjustments to heights and lengths of various components to keep everything correct.
Installed front and rear driveshaft disconnects, as well as free wheeling front hubs as the front differential is limited slip, I have not done anything regarding the rear limited slip differential.

My problem is... I hook up my tow bar from the motorhome to the front of the land cruiser, the land cruiser follows behind just fine while going straight, when I make a right turn, the motorhome has 8* rear steer so It will swing out in the opposite depiction at the beginning of the turn, the land cruiser starts to follow to the left, following the rear swing of the motorhome, and the self corrects and turns right to follow through the rest of the right turn.
The problem is when I go to make a left turn the land cruiser starts to follow right, begins to straighten out and instead of following to the left, the steering goes full hard right.

what do you think can be causing this?

I live full time in my 43' motorhome. I have flat towed my FJ cruiser for several years.

 

[OffRoadScott]

You might want to try and pull the front drive shaft to see if that makes a difference if so I would look into doing a PT AWD conversion.

 

[gordon5211]

You might want to try and pull the front drive shaft to see if that makes a difference if so I would look into doing a PT AWD conversion.

I have driveshaft disconnects on both front band rear and installed free wheeling front hubs to disable the front limited slip differential and also to be able to drive in 2 heel drive

 

[leonard_nemoy]

What's your caster angle after your lift?

 

[gordon5211]

What's your caster angle after your lift?

Toe is turned in 0.15 on both sides
Caster is 0.18 positive

 

[leonard_nemoy]

Toe is turned in 0.15 on both sides
Caster is 0.18 positive

There is your problem. Get your caster back to oem specs (2-4 degrees +) and I bet your problem is solved.

Right now your front wheels are like the front wheels of a shopping cart.

 

[gordon5211]

There is your problem. Get your caster back to oem specs (2-4 degrees +) and I bet your problem is solved.

Right now your front wheels are like the front wheels of a shopping cart.

won't that forward caster make the driveshaft and front differential come together at an odd angle?

 

[jfz80]

How to Flat tow your 80 series... safely.

Starting off, I am writing this to possibly help others who decide that they want to flat tow their 80 series. I want to be upfront and say I have not flat towed the 80 yet (except for around the block) and I don't know if flat towing is gonna wreck the tranny, transfer or anything else on the...

forum.ih8mud.com

And FSM guide

 

[leonard_nemoy]

won't that forward caster make the driveshaft and front differential come together at an odd angle?

It depends on how much caster correction you use and it depends on the method you use.

Lots of posts on proper caster angle posts to read.

80 series Caster Correction

Recently installed the icon 3” stage 1 suspension on my 97 LC. I installed the supplied caster correction poly bushings as a temporary fix until I could figure out a more permanent solution using OME rubber bushings. The poly bushings did NOT seem to correctly fix the caster as the front axle...

forum.ih8mud.com

caster correction 411?

i’m reading up on caster correction and would like to understand it but also the slee document (and the OME document) on caster correction bushings is hard to understand. slee seems to say to use a Plumb Bob which would imply you are dripping s line from a point while under the vehicle? but...

forum.ih8mud.com

Alignment/caster issues on the 80 series

Hey everyone, I have a 1996 land cruiser with a 4" lift kit from Slee, including the front control arm upgrade for caster correction. I got 35" Toyo MTs installed at the same time as the kit. Since the lift and tires were installed, followed by an alignment, the truck developed a consistent...

forum.ih8mud.com

 

[gordon5211]

How to Flat tow your 80 series... safely.

Starting off, I am writing this to possibly help others who decide that they want to flat tow their 80 series. I want to be upfront and say I have not flat towed the 80 yet (except for around the block) and I don't know if flat towing is gonna wreck the tranny, transfer or anything else on the...

forum.ih8mud.com

And FSM guide
View attachment 3173911

That’s why I’ve disconnected both driveshafts

 

[mudgudgeon]

I agree, you don't have adequate caster.
Without enough caster your front tires aren't going to return to centre,

Curious why you say the front diff is LSD?
Did you do a conversion to make it LSD, I don't think an LSD front diff in a Landcruiser was ever done by Toyota?

 

[gordon5211]

I agree, you don't have adequate caster.
Without enough caster your front tires aren't going to return to centre,

Curious why you say the front diff is LSD?
Did you do a conversion to make it LSD, I don't think an LSD front diff in a Landcruiser was ever done by Toyota?

This is a Japanese model

 

[gordon5211]

This is a Japanese model

When is add more caster, the connection between the driveshaft and the differential will be at an odd angle.
Will that cause any problems?

 

[BILT4ME]

When is add more caster, the connection between the driveshaft and the differential will be at an odd angle.
Will that cause any problems?

Anything above a 2-1/2" lift will bring on serious alignment and drive line issues that need to be addressed with DC drive shafts, caster correction through plates or replacement arms.

They can certainly be operated, but without correcting the drive line angles and drive shafts, you're asking for trouble.

 

[mudgudgeon]

This is a Japanese model

I saw that.

I still not aware of an LSD ever being used in a front diff by Toyota.
Do you mean it has a locking diff? ie, you turn the diff lock control knob on the dash to activate a locker?

 

[gordon5211]

I saw that.

I still not aware of an LSD ever being used in a front diff by Toyota.
Do you mean it has a locking diff? ie, you turn the diff lock control knob on the dash to activate a locker?

I only have automatic locking center differential, I’m going to be upgrading to ARB triple air lockers

 

[gordon5211]

Anything above a 2-1/2" lift will bring on serious alignment and drive line issues that need to be addressed with DC drive shafts, caster correction through plates or replacement arms.

They can certainly be operated, but without correcting the drive line angles and drive shafts, you're asking for trouble.

What is a DC driveshaft?

 

[BILT4ME]

What is a DC driveshaft?

Double Cardan

It has a CV joint on one end and it REQUIRES frequent greasing. Like every 1500 miles, religiously, depending on manufacturer.

Double Cardan Drive Shaft Solutions

The 2.0 looks like a great option. I have had great luck with all my Land Tank products, including one of his earlier DC’s. @landtank is there a published price for you to properly service/upgrade one of your older DC shafts? I am building another 80 and will buy a 2.0, thinking that would be...

forum.ih8mud.com

 

[leonard_nemoy]

Use some trunnion bearings to get a few more positive degrees of caster and send it.

The trunnion bearings probably won't cause any problems with the drive shaft.

If they do cause angle issues your in luck because you already have locking hubs. So all you would need to do is install a part time 4wd kit into the t case.

 

[gordon5211]

Use some trunnion bearings to get a few more positive degrees of caster and send it.

The trunnion bearings probably won't cause any problems with the drive shaft.

If they do cause angle issues your in luck because you already have locking hubs. So all you would need to do is install a part time 4wd kit into the t case.

Yes
I’m setting it up to be part time 4WD