Pitch and dives when braking

[letsgetdirty]

Hello all, i fitted a lift kit which has given me roughly 3inches of lift,i was happy with the handling and ride,its heavy duty so the ride felt firmer,i had to hit the brakes quite hard to day and blimey it frightened the life out me!! ....it dived and swerved to the right,and a long hard brake makes it swerve pitch and wallow,not really bad but enough to worry you,if i had to do an emergency stop goodness knows what would happen!! my brakes are spot on, new on the back good on the front and pulled up brilliant and true before the lift,has any one else had this??and i wondered did you stabilise it a bit more if you did?? strut brace?? landys eh!! hope all are well!! tris

[max-ie]

Hi, Mines a 90 with a two inch lift kit, articulation bars etc. It did the same under very heavy braking and like you i s"&@t myself when it happened. Thought it was my brakes at the time and checked drum brakes at rear but they were fine. Then had to take it off road last october so never really got to bottom of it.

[Guest diesel_jim]

I suspect its your panhard rod thats out of "adjustment" (althoug they're not adjustable... well, standard ones arn't)

picture it like this... the axle is "fixed" to the chassis by means of the panhard rod, left to right... so you can't move the axle "left or right" because of said arm? ok so far?

now, the panhard rod is made (at the factory) at a fixed length to correspond with the length of front springs fitted.

with a factory spring (give or take 1" or so for standard or HD versions), the chassis sits at a certain height above the axle, so the panhard rod is made to the proper length to make the axle sit exactly in the center line of the chassis (and more imprtantly, in line with the rear axle)

on a RHD vehicle (as the panhard rods are on the opposite side on LHD vehicles), if you lengthen the rod, the axle would be moved to the left, if you shorten it, it'll move to the right (because it attaches to the chassis on the RH side and onto the axle on the LH side)..

now..... if you fit longer springs in, you're increasing the distance between the axle and the chassis (hence the "lift"), and as the axle is attached by a solid bar (panhard rod) to the chassis, if you fit longer springs, then the axle will have to move over slightly (to the right, on a RHD truck)

lift it too far, and the front axle will be out of line with the rear axle (the tyres won't follow the same line) ... in short, the vehicle is "crabbing", so the panhard rod needs lenghening (only by 5 or 10mm) but it's enough, as you've found out, to make the handling very bad.

also, if the panhard rod is at too much of an "angle" (look at a factory vehicle, the panhard rod is almost horizontal-in line with the axle casing, but the more you lift a vehicle, the more "at an angle" the rod becomes) then you get whats called bump steer

You can get adjustable panhard rods from the likes of Rakeway, QT and scorpion

[letsgetdirty]

Jim that was well explained and easily understood!!makes sense to,im gonna get this sorted as soon as! thanks for your time mate

regards tris

[Mark]

It may also be an effect of loosing te self centreing on the steering as you have lost some of you castor on the front axle. Again there are ways around this, by fitting castor corrected radius arms or bushes, or by clocking the swivels. it's worth doing a search on all of this stuff as it is covered in some depth...

hth

Mark