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Front Axle Hop

Posted: Thu Jan 09, 2003 10:21 am
by Bodge
Got a strange front axle hop happening when I power out of corners :?: :?: :?:

It started when I replaced the front springs so I expect that is where the problem is but i have no idea how to cure it...

Currently 764's [to carry the 8274 and bullbar] in the front with 18" 180's in the rear. Rangie does sit a little nose high

What do you think?

Back springs too soft?
Shocks not up to it? [I have Koni adjustables front and rear set 3/4+ -quite firm]
Somethin else? :?

Posted: Thu Jan 09, 2003 3:05 pm
by max200tdi
Sounds like its tramping under power. But if springs were the only thing changed, it shouldn't be shocks or bushes..

The nose up might be the answer. Does it tramp both ways, left & right? If not, its probably something to do with the panhard rod. Is the angle excessive?

My guess is if it tramps turning right when the cars in roll, the panhard rod is too far from horizontal, and can't locate the driver front wheel properly

Regards
Max P

Posted: Thu Jan 09, 2003 6:40 pm
by v8grunt
How much lift has the vehicle got ?
In what condition is the suspension bushs and has the vehicle had a wheel alignment, are the koni shocks to suit the car or are they retro fitted from another vehicle also in what condition are the shocks.
Changing spring rates can have a lot to do with the harmonic vibrations created from the tyres. Finaly at what speed does this happen.

If the car is nose high the caster angle will be less than standard an will tend to be unstable at speed. this will also magnify any existing problems that may not have shown up prior to the spring change.

glen

Posted: Fri Jan 10, 2003 7:34 am
by Strange Rover
I would guess that the radius arm bushes at the axle end are stuffed and now for some reason with the extra lift they are causing problems. See how much movement you can get out of the redius arm bushes by leavering the axle to try to rotate backwards and forwards. If the bushes are flogged it will rotate easilly with a lot of freeplay.

Maybe your steering dampner is stuffed and now with the extra lift and loss of caster the front wheels want to shimmie from side to side under power??


Sam

Posted: Fri Jan 10, 2003 7:38 am
by Bodge
Its roughly 3" spring lift over stock - I had 2" prior to this.
Bushes are good - original rubber rather than poly - I change them regularily - Panhard and radius in the last 6 - 12 months.
Shocks are Koni replacements for Rangie - not sure of condition or age - they appeared to be working ok when I had them off when changing springs - although I haven't had them tested...
Castor is definitely out but it drives reasonably well on the road.

It happens at low speed - usually around round abouts and out of drive ways - the tighter the lock the more hop. Not sure if it hops both ways - it definitely does it on right lock as I go round the round abouts - I will check left tonight.

I also have a 2" Body lift which is contributing to the body roll and ultimately might not be helping the situation...

Posted: Fri Jan 10, 2003 8:08 am
by v8grunt
Hard to tell what the problem is without looking at the vehicle or driving it, but you could start with the basics and replace the steering dampner and get an alignment. if the caster angle is out to far you can get off set bushs to fix the problem. If you can't locate any off set bush let us know and i'll find some for you.

glen