bad bump steer on my GU

[Kermit]

hi i got aGU with a 7inch lift and running 36s and i got heaps bad bump steer any idears 2 fix it i can only do bout 50 ks i run 35s as well and dont get it as bad but its still their thanks guys

[PGS 4WD]

Lower it, your pan hard and steering rods must be at 30 degrees, or start moving mounts for the front and rear panhards to get them more horizontal. Could also be a faulty shocker.
Joel

[purplebus]

had exactly the same on my gq 5'' lift with castor correction plates and 35's was perfect for 3 years then just started doing it one day. after all the usual suspects were replaced. i went for a wheel alignment to check that it wasn't that. they can check the castor as well and mine was almost zero degrees, supposed to be between 3 & 4 degrees from memory, but the wheel aligner will know.
i just pressed in some 3 degree castor correction bushes into my arms and problem solved.dont know what happened but it had changed somehow(maybe an abuse issue??). it drives perfect now.

[Yom]

Lower it, your pan hard and steering rods must be at 30 degrees, or start moving mounts for the front and rear panhards to get them more horizontal. Could also be a faulty shocker.
Joel

Not just that but if he's not using the right radius arms the front end geometry will be all out and bump force will be going through the chassis and not the shocks.

[Kermit]

can any 1 think of any think els my lift is only bout 6 months old and had new bushes put in bout 3 months ago

[tomahawkracefab]

if front panhard is same arc as steering drag link..( which should be )...how does height or travel affect steering? don't think so...no-one mentions wheel offset...wheel further out from kingpin is more leverage and feedback to steering wheel..ie, wheels hits bump and is pushed back...if king pin is in line with centre of wheel track...king pin takes hit square on and does'nt try to turn wheel back....bit more castor than std doesnt hurt to help larger tyres 'return to centre' and stop death wobbles...IMO....hope its some food for thought....

[Kermit]

my new rims are - 47 offset do ya think new king pin bearings will help and i got castor plates sould i get som of those drop radios arms. my tie rods a bit bent 2 would that help the prob

[SuperiorEngineering]

Are you talking about head shake, shimmy or bump steer? all totally different problems. I read you say bump steer but a lot of guys get it mixed up.
What is the condition of ALL you bushes in the front end, they must be very good.? Poly or genuine?
What is the condition of the tyres you use on road and have you tried different ones?
What is your true lift by bump stop height?
What is your caster reading taken with the tyres that are used on road?
This is a starting point to find your problem.
We have seen a few GQ/GU's with the mounts incorrectly welded on the diff from factory giving up to 3 degrees of incorrect caster , this is why you should get a wheel alignment done.
We have done many lifts in all different sizes ranging from 2-7 inch and if done correctly their is no reason they should not drive very well on and off the road.
Caster plates are rubbish and so are dropped radius arms if you are trying to get a good ride, dropped radius arms are going to do the exact same thing as a set of caster plates but your pins at the rear of the diff will be horizontal again and you will not lose ground clearance for $1300 "JEEZ WHAT A BARGAIN"
Drop boxes will help with most problems as they will drop the rear of the radius arm back down to the same geometry as nissan designed them to be approx 2 inches above the centre line of the diff which will support the diff. Drop radius arms and caster plates position the rear pin to high above the centre line of the diff and this will allow the diff to want to push back and under the car during impacts, thus causing the harsh ride to be transfered up the arms and not up the shock and coil. The more verticle the radius arms become the more head shake, shimmy will show.
Drag links and tie rods must be in perfect condition when you have a lifted nissan with caster plates.
If you have only driven with caster plates or radius arms you wont now how good you nissan can drive till you try drop boxes.
And just to refresh the readers we manufacture drop boxes, drop radius arms , super flex arms , caster plates and resell radius arm bushes so it is of no benefit to push one particlur item, this is our opinion from fitting and test driving nissan's everyday.

[tomahawkracefab]

x 2 , good advice there....

[vn15]

Agree with the two above, have 6"+ lift on my modified GQ. Bought some drop boxes instead of the plates I had before. Waay better, it levels the radius arms, so goodbye to bump steer, well for me it was

Cheers

[badger]

pgs4wd i wouldnt advertise my own business name whilst giving poor advise like to lower your panhard mounts etc on a gq

ever heard of roll axis? ever seen when happens to a lifted patrols handeling when you lower panhard rod mounts................. they get real scary keep trying to lay over

you will also find that aslong as the steering arm and panhard cross eachother close to the centre of the car panhard and steering angles will have mext to nill effect on steering.

mick from supereior is right. try drop boxes and check all the bushes, rubbers, king pins and tie rods oh and it could also be using the wrong shocks and coils for the weight of the car

[fatassgq]

By lifting the lower panhard rod mount up you will raise your roll centre point and this imo is a better option but is rarely ever done.

Joel is obviously a switched on dude badger (see some of his other work/posts) so prob good idea to chill a bit. I do believe that dropping the top mount is not a good idea but joel doesn't actually say anything about dropping the top mount he just said move mounts if you have too.

If you change your panhard rod angle the drag link angle will also have to be changed to suit and herein lies the problem. TOO HARD in almost all cases and generally not worth it on a street driven car.
On a true 7" lifted patrol the panhard/draglink relationship would without doubt be 'out' of alignment enough to cause problems. All you have to do is look at the angles of a std patrol/cruiser compared to a lifted one! This at the end of the day is the true cause of bumpsteer. If that is what we are actually talking about and not any of the many other problems lifted Nissans have!

One of the MOST IMPORTANT things when dealing with patrols is to first work out exactly what height your truck is at. Just cause ya bought 5" coils don't mean you have five inch lift etc

I believe also that it is not just the relationship of the panhard draglink that matter here but also leverage (similar thing to the angle of the radius arms problem) but this is not the cause bumpsteer .

Nissans are fun but as Mick has said there is no reason a lifted truck has to drive like a pig if you are willing to spend the time and get it right

Brian

[Kermit]

thanks heaps guys all good should help