Truck pulls left after castor plates (1 Viewer)

[Boonjooce]

I’ve just installed Dobinsons 5 degree castor correction plates in my 80 with 3-3.5” lift. Handles great now. Much better road manners.

But now the truck pulls left (it’s a right hand drive).

didnt do it before the plates were installed.
I’ve loosened them, taken any pressure off the radius arms and re tightened, but it still pulls left. It’s not really bad but enough to do something about it.

I don’t have an adjustable pandhard - that wouldn’t cause the truck to pull left would it?

any ideas ?

cheers

 

[categorytheory]

I’ve just installed Dobinsons 5 degree castor correction plates in my 80 with 3-3.5” lift. Handles great now. Much better road manners.

But now the truck pulls left (it’s a right hand drive).

didnt do it before the plates were installed.
I’ve loosened them, taken any pressure off the radius arms and re tightened, but it still pulls left. It’s not really bad but enough to do something about it.

I don’t have an adjustable pandhard - that wouldn’t cause the truck to pull left would it?

any ideas ?

cheers
View attachment 2598794

Go to a shop and have the wheels realigned.

 

[leonard_nemoy]

I would 2nd the alignment before you do anything. Numbers are needed for an accurate diagnosis if it still pulls left after the alignment.

 

[Boonjooce]

just had a wheel alignment and the toe was adjusted a little bit still pulls left.

I have a bit too much positive castor amd it’s not EXACT on each side. But would this cause my pull?

nb truck drives great apart from the pull (tracks great)

 

[retrofive]

Pretty high caster IMHO. Spec is closer to 2-4°

but something silly like dragging brake or nutz ?

 

[leonard_nemoy]

What size tires do you have? Do you have OEM control arm bushings or old caster correction bushings installed?

I am no expert but the way my alignment guy explained it, that difference in caster could cause the rig to pull one way or another. He said that a good alignment guy will make a small change in caster from one side to the other to make a vehicle drive straight on crowned roads. For example a vehicle would pull left on a perfectly flat surface but most roads are crowned to the right so in reality the vehicle will drive straight on real roads.

 

[Railwelder93]

They can’t adjust caster.

How did the bushings look?

 

[fjc-man]

So alignment talk - vehicle will drift to the side with the most (+) camber, or the side with the least (-) caster. In your case, it might be easier to come closer to evening out the camber.

 

[COYS]

Some of you guys must have the Land Cruiser GT3 edition with all this camber and caster adjustment talk.

Your caster value does exceed stock specs, but very few on this forum run a bone stock 80. I’m in the low 4s myself running Delta arms with OME lift with zero drivetrain vibes at any speed. I’ll take that as a W.

It’s a bit of a fool’$ errand to try and get it to track perfectly straight because the suspension has so many parts that make up the whole. You can only decide for yourself whether the juice is worth the squeeze. Gl!

 

[fjc-man]

Can you get eccentric style knuckle bearing races?

 

[Railwelder93]

I would do panhard correction, and check bushings and wheel bearings...etc.

I seriously doubt any kind of asymmetric knuckle bearing shenanigans are needed

 

[leonard_nemoy]

They can’t adjust caster.

How did the bushings look?

Some of you guys must have the Land Cruiser GT3 edition with all this camber and caster adjustment talk.

Your caster value does exceed stock specs, but very few on this forum run a bone stock 80. I’m in the low 4s myself running Delta arms with OME lift with zero drivetrain vibes at any speed. I’ll take that as a W.

It’s a bit of a fool’$ errand to try and get it to track perfectly straight because the suspension has so many parts that make up the whole. You can only decide for yourself whether the juice is worth the squeeze. Gl!

I know you cannot adjust caster on an 80 series. Maybe I should have been more clear, but I never said that you can adjust caster on an 80 series. I did say "a good alignment guy will make a small change in caster from one side to the other to make A VEHICLE drive straight on crowned roads."

A vehicle does not mean an 80 series. I was just trying to explain how a difference in caster from one side to the other can affect the way a vehicle pulls to one side or the other.


To the OP, does your rig have OEM control arm bushings installed? If so, how old are they?

 

[Boonjooce]

I would do panhard correction, and check bushings and wheel bearings...etc.

I seriously doubt any kind of asymmetric knuckle bearing shenanigans are needed

Would the panhard being possibly slightly out of center cause pull to the left? I wouldn’t think so?

 

[Railwelder93]

Would the panhard being possibly slightly out of center cause pull to the left? I wouldn’t think so?

Not sure but I would have one on a 3.5in lift.

I think the first this to look at would definitely be radius arm bushings. How did they look? Did it have regular bushings or CC bushings?

 

[Boonjooce]

So alignment talk - vehicle will drift to the side with the most (+) camber, or the side with the least (-) caster. In your case, it might be easier to come closer to evening out the camber.

So the slight difference my castor would cause the drift? If so I wonder if one of the castor plates isn’t sitting 100% flush with the radius arm axle mount when I installed them. I did have to grind a little metal off the side of the mount weld to sit flush - wonder if I need to grind more...

 

[BILT4ME]

My question is why did you do the 5° plates? That seems excessive.

 

[Railwelder93]

The dobinsons 3.5 kit comes with *5 plates. However I guess it depends on what you started with. Not 100% sure on that.

Edit
By “what you started with” I mean castor #s

 

[leonard_nemoy]

Although your caster is a bit higher than OEM specs, it is probably just right for a "true" 35 or a 37. The OEM caster specs were engineered for OEM tires size. What size tires are you going to be running?

 

[Boonjooce]

Going to be running 33” tyres.
I’m probably being a little too picky it doesn’t pull left that at bad.

just need to know if getting my castor as close to each other as possible would give me straight tracking...

In other words if I had 5*20 on both sides it wouldn’t pull?
The slightly over oem spec castor (2-4*) is to be honest the nicest road manners I’ve had any of my cruisers (a few 78s and 80s)

 

[leonard_nemoy]

just need to know if getting my castor as close to each other as possible would give me straight tracking...

The way I understand it, yes that would give you straight tracking assuming everything else susoension related was 100% up to par. Things like panhard geometry and bushings.

My 97 has about 3" of lift in the front and 2" in the back and it drives very straight with about 4 degrees positive caster. And I am running OEM panhards for reference. Just remeber every 80 series is different.

How old are the tires? Uneven worn tires could cause a pull. Lots of variables.....