40 series 4 link

[UZJ40]

Am building a 40series from the ground up. I have put a 1UZFE, 4.0lt V8 in with a 100series 5 speed an transfer. This was quite simple to put in.
the body is being done at the moment, next job is the suspension.

has anyone done or can help with advice on doing a 4 link front and rear on it?

any advice or help would be greatly appreciated.

[bogged]

sounds like an interesting project, any photos??

[eddie]

photos of instill would be grate

[ORSM45]

go a 5 link on the front. 4 links will have bump steer.

theres lots of people running 4 links/A frames in the rear of hilux's, etc. on this board. do a search as there has been pretty detailed threads on it.

[MY45]

go a 5 link on the front. 4 links will have bump steer.

theres lots of people running 4 links/A frames in the rear of hilux's, etc. on this board. do a search as there has been pretty detailed threads on it.

383 why would you get bump steer ? Do you you know why it happens? Surely they could be designed so that it doesn't

[ORSM45]

if you run a A frame/4link (basically the same thing) up front, you will get bump steer. (the same as a leaf sprung vehicle)

if you put the car on a hoist lift it up. the axle stays central in the chassis when it drops away.

now the drag link moves in an arc. look at a circle, your pitman arm is in the middle of that circle and when the axle drops vertically, the draglink starts pulling horizontally.

with a 5 link. you have a panhard rod. which runs parallel to the draglink taking the same arc (ideally) so the axle moves horizontally with the draglink.

to minimise bumpsteer you should get the draglink as horizontal as possible. look at your circle again you will see that it has to move alot further vertically before it starts moving horizontally.

MaccA

[Bush65]

go a 5 link on the front. 4 links will have bump steer.

theres lots of people running 4 links/A frames in the rear of hilux's, etc. on this board. do a search as there has been pretty detailed threads on it.

383 why would you get bump steer ? Do you you know why it happens? Surely they could be designed so that it doesn't

You get bump steer because the axle stays centred as the wheel end of the draglink travels through an arc.

Yes can be designed so it doesn't. Either hydraulic steering (not legal on road) or use steering linkage like on dobbins truck (draglink runs south-north, I don't recall the correct term to describe this system).

[dumbdunce]

to minimise bumpsteer you should get the draglink as horizontal as possible.
MaccA

everything else you say is spot on, however this bit is ONLY true if the panhard rod is also as horizontal as possible. ideally you want the panhard rod and the draglink to be, in order of priority to mimise bumpsteer, (1) parallel, (2) as close as possible to equal lengths (3) horzontal at rest.

if the draglink is horizontal but the panhard rod is angled then the axle will move more than the end of the panhard under bump, then you get reverse bumpsteer.

[ORSM45]

to minimise bumpsteer you should get the draglink as horizontal as possible.
MaccA

everything else you say is spot on, however this bit is ONLY true if the panhard rod is also as horizontal as possible. ideally you want the panhard rod and the draglink to be, in order of priority to mimise bumpsteer, (1) parallel, (2) as close as possible to equal lengths (3) horzontal at rest.

if the draglink is horizontal but the panhard rod is angled then the axle will move more than the end of the panhard under bump, then you get reverse bumpsteer.

yeah sorry, i guess you could take it the wrong way as i didnt specify.

it meant to read: "to minimise bumpsteer in a 4-link, you should get the draglink as horizontal as possible."

MaccA

[dumbdunce]

yeah sorry, i guess you could take it the wrong way as i didnt specify.

it meant to read: "to minimise bumpsteer in a 4-link, you should get the draglink as horizontal as possible."

MaccA

true. However a 4-link front will always have noticable bumpsteer no matter how well you set it up - the axle will tend to go straight up and down and the draglink end will go in an arc. with a 5 link front, the drag link and the axle can be made to travel through very similar arcs therefore eliminating all noticable bump/flex steer.

cheers

Brian

[DAZ]

if you want to go to the link below that will take you to the build of my truck which i have put 80 serries diffs the front i will change to a 5 link at a later date which i don't see being a big job