Outer Limits 4x4 Board

I can't find the workshop manual for my HZJ105R and need to make sure that it has the correct castor angle. 1.5 degres rings a bell, but not I'm certin.
My 4" tough dog kit has givin me a shit load of bump steer even though it has 3 deg castor bushes. The kit is a HD kit and I suspect that it lifted it more to the tune of a 5" lift. Might have to get some 5 deg castor plates, but I need to check before I go spending 200 bucks.
Can some one confirm the correct castor angle for me????????

Cheers,
Busty

Bumpsteer is a separate problem to caster and is caused by the lift, not by the caster being out of spec.

Steve.

u need a dropped pitman arm or a real good steering dampener.

A steering damper has no effect on bumpsteer. Bumpsteer is 100% a function of steering geometry. "clamping" the steering at a certain point, either at the axle or at the pitman arm, will have no effect on how far the steering moves when it cycles, only how much you feel the steering wheel move in your hands.

The front wheels are still doing the same thing relative to the direction of the car's travel.

If the wheels move left and right as the suspension cycles, That's bumpsteer, and no damper in the world will stop it.

Steve.

Its is already fitted with a new 4WAY RTC and it still wanders and has bump steer. Probably help if the roads out here werent so bumpy. I still want to check my castor, so could some one please answer my question and let me know if I am correct in saying that the castor angle should be 1.5 deg, if not what should it be???

are you sure you know what bump steer is?

This is where when the wheels moves up or down they turn. It is 100% due to steering gemoetry, not your caster.

By lifing the car 5" you have made your relay rod run down on a more significant angle.

This means when the wheel on the side where the relay rod connects lifts up (passenger side?), it flattens the relay rod which forces both wheels to turn.

To fix this you need to make your relay rod parallell to your panhard rod, so that as that side of the diff lifts, the diff moves in an arc which matches your relay rod.

Ive never had a look at a 105 suspension and steering setups. I would think toyota would have the panhard rod and relay rod coming down to the same end of the diff, and that they would have had them roughly paralell.

However, by lifting it you have had to extend your panhard rod, and your relay rod, perhaps extending these has caused them to move in a different manner that origonal.

Shadow wrote:are you sure you know what bump steer is?

This is where when the wheels moves up or down they turn. It is 100% due to steering gemoetry, not your caster.

By lifing the car 5" you have made your relay rod run down on a more significant angle.

This means when the wheel on the side where the relay rod connects lifts up (passenger side?), it flattens the relay rod which forces both wheels to turn.

To fix this you need to make your relay rod parallell to your panhard rod, so that as that side of the diff lifts, the diff moves in an arc which matches your relay rod.

Ive never had a look at a 105 suspension and steering setups. I would think toyota would have the panhard rod and relay rod coming down to the same end of the diff, and that they would have had them roughly paralell.

However, by lifting it you have had to extend your panhard rod, and your relay rod, perhaps extending these has caused them to move in a different manner that origonal.

What you have said makes sense, how ever the relay rod and panhard are both parralell, I can post the pics to prove it. I do know what bump steer is as Im the person driving the car that wants to swing from one side of the road to the other every time I hit big bump or big puddle of water @ 100KPH. The car wants to wander a fair bit as well. So I'll pose a different question then and see if some one can help.

If my car has bump steer and wanders, but my panhard and relay rod are parralell and the castor appears to be out, what can I do to rectifiy the problem.
On top of that I also pose the question of what is the castor angle supposed to be? 1.5deg????
I swear it would be quicker for me to drive 200klm to Mackay and buy a new workshop manual to get the answers to my orginal question.

balzackracing wrote:

Shadow wrote:are you sure you know what bump steer is?

This is where when the wheels moves up or down they turn. It is 100% due to steering gemoetry, not your caster.

By lifing the car 5" you have made your relay rod run down on a more significant angle.

This means when the wheel on the side where the relay rod connects lifts up (passenger side?), it flattens the relay rod which forces both wheels to turn.

To fix this you need to make your relay rod parallell to your panhard rod, so that as that side of the diff lifts, the diff moves in an arc which matches your relay rod.

Ive never had a look at a 105 suspension and steering setups. I would think toyota would have the panhard rod and relay rod coming down to the same end of the diff, and that they would have had them roughly paralell.

However, by lifting it you have had to extend your panhard rod, and your relay rod, perhaps extending these has caused them to move in a different manner that origonal.

What you have said makes sense, how ever the relay rod and panhard are both parralell, I can post the pics to prove it. I do know what bump steer is as Im the person driving the car that wants to swing from one side of the road to the other every time I hit big bump or big puddle of water @ 100KPH. The car wants to wander a fair bit as well. So I'll pose a different question then and see if some one can help.

If my car has bump steer and wanders, but my panhard and relay rod are parralell and the castor appears to be out, what can I do to rectifiy the problem.
On top of that I also pose the question of what is the castor angle supposed to be? 1.5deg????
I swear it would be quicker for me to drive 200klm to Mackay and buy a new workshop manual to get the answers to my orginal question.

ok, if panhard is pretty much parallell to the relay rod, then it wont be bump steer (as the defenition of bump steer is directly related to steering geometry, not caster).

what you have is probably as you say, a problem with your caster. I googled and could not find what the caster is supposed to be sorry.

However, In my OEM 60 series manual, the caster is supposed to be either 0degree50minutes RG(base model) or 1degree5minutes RV(GX GXL GXV) for a HJ60.

Last time I got a wheel alignment on the 40 I got the castor checked and was -1.5 degrees. Was told for a rig on 33-35's and with power steering castor should ideally be around +4 degrees.

Caster CAN cause bump steer, but you need alot of it to feel it. Toe can too, worn bushes can too.

I would go into a diatribe about how the little japanese engineers at toyota who get paid lots and lots of yen to set up the panhard and steering from factory so that this doesnt happen and then people like us go along and nullify all their hard work by moddifying the suspension but im not going to.

And for the record, your panhard rod doesnt just need to be parallel, it also needs to be as close to the same length as your steering link too, think parallelogram, not trapezoid.

Cheer's
I have a bit of time off during the weekend Ill measure mine up and see how close it is 4deg.