I guess it's always done this but since I changed my wheels it seems more noticeable and I think it's getting worse.

 

When I go over a bump, (Scottish roads being in the state they are means this happens a lot!), the rear of the car shimmys a bit. I can only think it's like bump steer on the back. As I say it's getting quite disconcerting and I'm getting a little uneasy with the car's straight line stability at motorway speeds.

 

I had the car four way alligned when I has new Hicas arms fitted under a year ago.

 

So is this common/expected or do I need the car realligned or is it time for a Hicas deletion?

Does sound like the HICAS is getting fussy. I haven't had to deal with HICAS on the Z, mine was already locked out, but I did have a bad experience in the GTR with it. I had a 12" sub in the boot of my car, was going round a roundabout with some loud music playing and the rear end went psycho and tried to slam me into a lamp post, I was later told by other people, that HICAS doesn't like loud noises/vibration, so potentially this could now be the problem you're experiencing when going over bumps?

 

There are plenty of people here far more knowledgable about the Z in general and HICAS, so I'm sure someone can give you a more definitive answer, but it does sound likely.

jack the rear end up, and check the wheels for play, first by holding it at 12 o'clock and 6 o'clock, and then at 9 o'clock and 3 o'clock, give em a good waggle, see if there is any play... when you had you hicas arms fitted, was it just the inners (track rods) or were the outer ball joints changed too?

I was later told by other people, that HICAS doesn't like loud noises/vibration, so potentially this could now be the problem you're experiencing when going over bumps?

 

Hmm, well there's a thought!

 

Around the same time I changed the wheels, I replaced the exhaust for one that is louder than the previous. That said, it's not much louder on the outside but makes the car reverberate something awful at certain engine speeds.

 

Typically caused by either Worn rear shocks or hicas arms.

Typically caused by either Worn rear shocks or hicas arms.

 

Had new HICAS arms less than a year ago.

 

Keep 'em comin' lads, at this rate I'll be rebuilding the whole rear end!! LOL

jack the rear end up, and check the wheels for play, first by holding it at 12 o'clock and 6 o'clock, and then at 9 o'clock and 3 o'clock, give em a good waggle, see if there is any play... when you had you hicas arms fitted, was it just the inners (track rods) or were the outer ball joints changed too?

 

Good question. The whole lot I think but I can't remember for sure. Shameful as I was under the car at the time. Damn my memory!

Had new HICAS arms less than a year ago.

 

Keep 'em comin' lads, at this rate I'll be rebuilding the whole rear end!! LOL

 

Rear shocks then ;)

 

tbh, 90% of the z's out there are suffering with worn shocks and suspension bushes that are waaaay past their lifetime. The z is a heavy car and eats suspension components. Very few Z's actually handle or ride anywhere near as well as they should. Even just replacing with new stock components turns a heavy, wobbly, lethergic Z into a lighter feeling more responsive sports car again.

Edited June 27, 201114 yr by Yowser

Rear shocks then ;)

 

tbh, 90% of the z's out there are suffering with worn shocks and suspension bushes that are waaaay past their lifetime. The z is a heavy car and eats suspension components. Very few Z's actually handle or ride anywhere near as well as they should. Even just replacing with new stock components turns a heavy, wobbly, lethergic Z into a lighter feeling more responsive sports car again.

 

I'll have 'em checked out.

 

I take it they don't have to be leaking, just worn?

 

What's a set of shocks gonna run me?

I'll have 'em checked out.

 

I take it they don't have to be leaking, just worn?

 

What's a set of shocks gonna run me?

 

stock rears are cheap, about £40 per side.

worth changing anyway really, if they are really old....

Easy job?

yeah piece of cake, apart from the fact you have to dismantle the entire back end of your car on the interior, just to get to the shock tops!

 

Once you've removed the door sill covers, the rubber up the B pillar, the rear seats, the rear quarters and then the strut topping plastic in your boot, it's just two bolts on top, then one at the bottom. Little tip, a jack of some kind will help moving the hub assembly up and down when freeing the old and fitting the new shocks.

If it's moving from side to side it defo sounds like HiCAS, perhaps you didn't change the inner and outer as you thought.

 

If it bounces up and down then it's defo the shockers and as above they're one of the cheaper zed parts ! Easy to check if it is the shockers, just push hard on a rear corner and see how firm or soft it is. If they're good you'll hardly move it, if not you'll know !

i have some new ish rear shocks taken off my breaker, see my thread here http://300zx.co.uk/forums/showthread.php?t=151844

Got a set of coilovers kicking about if your wanting interested?