Cant keep my ass on the road

[71_240Z]

Can you say 'arse?' :paranoid:

I just got my Z running again after it had sat in the woods for a few years. No mice in the carbs (did you see that post!??). I'm trying work through all of the mechanics before I tackle the cosmetics, so I have been driving back and forth to work a few days a week.

Every time I hit a curve too hard, the back end lets go of the pavement and scares me to death. I am not talking about racing speeds. Im talking about taking right hand turn into my neighborhood at about 20 to 30 mph on bone dry pavement. Something you would expect a Z to easily handle. My mazda 323 (four door sedan) will take the same curves at the same speed and stick to the road.

My tires are newish. I can hardly MAKE the front tires slide even when I lay on the brakes, so I dont think its the tires. If I really get on it, the back tires bark when I shift into 2nd and even 3rd (sometimes).

What do I need to adjust to keep my back end on the road?

Any ideas?

Would a simple strut replacement solve the problem? I think they need replacement, but I don't want to take everything apart, then put every thing back together and wind up with the same problem.

The problem is even more pronounced when I hit a bumpy curve - even a small bump seems to render the back wheels airborne. Thats why I suspect struts. But I dont really know much about suspension.

The struts on the front are a month old. I replaced them when I rebuilt my front brake system (toyota conversion).

Any ideas would be greatly appreciated.

Thanks.

-Barry

[Arne]

Rear struts are definitely a prime suspect. I recall it used to be recommended that if you were going to replace struts/shocks one end at a time, to always do the rear first. Don't know that I've heard that repeated in quite a while - decades maybe. But the reason was to maintain stability on bad road surfaces.

Similarly, there was old recommendations that if you had mis-matched sets of tires, the higher performance should always be on the rear. Same type of issues.

[bpilati]

My rear struts are completely shot and my Z doesn't do that, and I've taken onramps at 70 mph.

[71ZZZZZ]

Was the rear susp. ever modified with higher rate springs? It seems that if the struts have failed paired with the stiffer springs might result in this...is it more of a skipping rather than an undulating bounce?

[71_240Z]

Was the rear susp. ever modified with higher rate springs? It seems that if the struts have failed paired with the stiffer springs might result in this...is it more of a skipping rather than an undulating bounce?

The springs are stock. As far as I know, the struts are orignial too.

The back tires DO bounce around a bit on a smooth straight road. I cant really feel it (too much), but a friend who was following me said the back tires were bouncing a lot.

When I am cornering hard and the pavement has ANY imperfection in it, the back end starts sliding.

I figured the straight ahead bouncing was caused by an imbalanced tire, but now that you mention it, I guess it may all be related to the same problem.

[71ZZZZZ]

How does the car respond when you press down on either rear corner (while parked)...does it give in easily to the force of your weight? I had a Pontiac back in the day that needed new shocks...it had an uncontrollable bounce to it regardless of road condition...I'm confused by the skipping/sliding comment...are your tires inflated properly?

[Mat M]

The springs are stock. As far as I know, the struts are orignial too.

The back tires DO bounce around a bit on a smooth straight road. I cant really feel it (too much), but a friend who was following me said the back tires were bouncing a lot.

When I am cornering hard and the pavement has ANY imperfection in it, the back end starts sliding.

I figured the straight ahead bouncing was caused by an imbalanced tire, but now that you mention it, I guess it may all be related to the same problem.

Same thing happened when I had my 83 RX-7. Tires were treadwear 400 (elcheapos, although new) and the shocks were original to the car. Better tires and shocks/struts all around helped immensely.

[260DET]

As 71ZZZZZZZZZZZ said, check the rear end suspension movement both sides. For your car to behave like you describe I suspect something fairly dramatic, like a partly seized strut or anti sway bar. Check underneath too for something loose or broken in the suspension.

[mlc240z]

i always thought that was a sign of weak struts/shocks.

if you are getting straight line wheel hop, then you have virtually no dampening of the spring rebound at all.

when you are cornering and the tire bounces, you lose grip on that tire. all the force is then "transferred" (lousy reference but i hope you see what i mean) to the other wheel. more force overcomes other wheel's grip, or that tire hits some bump also and lifts. someone who knows suspensions can probably explain it better or correct me if wrong.

assuming stock spring rates, i'd agree about checking the struts.

[71_240Z]

I checked underneath and nothing seems to be broken or disconnected. It looks pretty much like the Haynes manual.

I guess I will try the struts. I will probably just use whatever Autozone carries (near OEM) unless there is some aftermarket strut that is far superior. My goal is to drive, not to race - except for an occasional autocross.

I am also trying to figure out if I need new springs. I saw the post by carl beck and his OEM springs, but I can't figure out why springs go bad. Mine are still "springy."

Any idea how to assess the need for spring replacement?

[Arne]

I would recommend that you use the same brand and grade of struts in the rear as you put in the front last month. Keep the valving matched and compatible. Don't put the cheap AutoZone struts (Gabriel or Monroe) in the rear unless that's what's in the front too. If the front got KYB or Tokico, use the same on the rear.

[71ZZZZZ]

I would recommend that you use the same brand and grade of struts in the rear as you put in the front last month. Keep the valving matched and compatible. Don't put the cheap AutoZone struts (Gabriel or Monroe) in the rear unless that's what's in the front too. If the front got KYB or Tokico, use the same on the rear.

I just went through some of this, having had KYBs now Tokicos both non-adjustable gas struts...if you're going to stay with stock springs then the KYBs should be fine...if you plan to lower then the Tokicos seem like the better match...I'm running Eibach ProKits/Tokico (blue) and am very happy with the ride performance...